0:00:02 > 0:00:05We're a nation of biscuit lovers.
0:00:05 > 0:00:08This year, we'll work our way through enough of them
0:00:08 > 0:00:10to fill over 30,000 lorries!
0:00:12 > 0:00:16That means we Brits are tucking into 90 million biscuits a day,
0:00:16 > 0:00:19more than any other country in Europe.
0:00:21 > 0:00:25Whether you prefer them smothered in chocolate or plain and simple,
0:00:25 > 0:00:27everyone's got their favourite.
0:00:28 > 0:00:32And where's the best place to find out how they're made?
0:00:32 > 0:00:35How about the largest biscuit factory in Europe?
0:00:41 > 0:00:43I'm Gregg Wallace, and tonight,
0:00:43 > 0:00:46I'll join the race to keep up with demand.
0:00:46 > 0:00:49Do you know how many biscuits are passing our nose every minute?
0:00:49 > 0:00:51Over 3,000.
0:00:52 > 0:00:54I'm Cherry Healey,
0:00:54 > 0:00:58and I'm going to be making a very expensive biscuit-cutter
0:00:58 > 0:01:01out of thousands of pounds' worth of bronze.
0:01:01 > 0:01:04And answering the ultimate question.
0:01:04 > 0:01:07Are you a dunker or not a dunker?
0:01:07 > 0:01:12I get scientific proof that dunking makes your biscuit taste better.
0:01:12 > 0:01:15This is not a comfortable biscuit-eating experience.
0:01:16 > 0:01:19And historian Ruth Goodman's going back in time
0:01:19 > 0:01:21to when biscuits could cure the sick.
0:01:22 > 0:01:25"Being full of wind and out of order,
0:01:25 > 0:01:27"and there called for a biscuit."
0:01:29 > 0:01:3480 million biscuits are baked in this factory every single day.
0:01:34 > 0:01:38And we're going to reveal what a mammoth task that is.
0:01:38 > 0:01:40Welcome to Inside The Factory.
0:02:01 > 0:02:04This is the McVitie's factory in Harlesden, North London,
0:02:04 > 0:02:12where 580 workers churn out 2,500 tonnes of biscuits every week!
0:02:13 > 0:02:17That's over a quarter of all the biscuits we consume in the UK.
0:02:17 > 0:02:20They make 22 different varieties here.
0:02:20 > 0:02:24From hobnobs and rich teas to savoury snacks and mini-cheddars.
0:02:27 > 0:02:30Tonight we'll learn how they make the nation's favourite,
0:02:30 > 0:02:32the chocolate digestive.
0:02:32 > 0:02:35Which is nice, because that's my favourite too.
0:02:40 > 0:02:45This 50,000-square-metre factory opened back in 1902.
0:02:45 > 0:02:48It's been making chocolate digestives since 1925.
0:02:50 > 0:02:53The process begins with the delivery of flour,
0:02:53 > 0:02:55just as it has for the past 92 years.
0:02:58 > 0:03:00Head of intake is Mike Kiley.
0:03:02 > 0:03:04Chocolate biscuits start here, do they?
0:03:04 > 0:03:06- Yes, they do. - How much flour in there?
0:03:06 > 0:03:08- 28 tonne.- 28 tonnes?
0:03:10 > 0:03:12And how often does a truck of flour turn up?
0:03:12 > 0:03:16- Seven to eight times a day. - A day?- Yep.- Not a week?- No, a day.
0:03:16 > 0:03:19- Shall we get this thing unloaded? - Yeah. All right, buddy.
0:03:21 > 0:03:23- What's that, mate? - This is a control switch for...
0:03:23 > 0:03:25- Are you going to let me do it? - You can have a go.
0:03:25 > 0:03:27You need to press the green button,
0:03:27 > 0:03:31take your finger off that and press the yellow button for up.
0:03:31 > 0:03:35- So, green button...- Green button and now the yellow button, below it.
0:03:35 > 0:03:38- Wahey! Wahey! - You've got lift-off.
0:03:38 > 0:03:41'That gives me a great sense of power.
0:03:41 > 0:03:45'Hydraulics jack the front of the tanker eight metres into the air.'
0:03:45 > 0:03:48- That's a beast of a machine, innit?- Yeah, yeah.
0:03:49 > 0:03:51So, I'm now moving 28 tonnes of flour?
0:03:51 > 0:03:54- Yeah.- That might be the biggest thing I've ever moved.
0:03:56 > 0:03:58'Gravity does all the hard work
0:03:58 > 0:04:01'and the flour falls down towards the back.
0:04:01 > 0:04:05'A quick pat of the tank confirms there's no trapped air.'
0:04:05 > 0:04:07Yeah, you can stop now.
0:04:07 > 0:04:10There's plenty of flour at the back of the tank now.
0:04:10 > 0:04:13'Which means we can now blow it through into the factory.'
0:04:13 > 0:04:17Push your lever down. That'll allow the flour to travel.
0:04:17 > 0:04:19Go for it. With all your might.
0:04:20 > 0:04:23'Our biscuit production line begins.'
0:04:23 > 0:04:24Yes!
0:04:24 > 0:04:27'A pneumatic pump pushes the flour out of the tanker
0:04:27 > 0:04:31'and into a 40-tonne silo in ingredients intake.'
0:04:31 > 0:04:34How long is that going to take to unload?
0:04:34 > 0:04:36That's going to take about an hour and 15 minutes.
0:04:36 > 0:04:38- All right, we'll leave you to it. - Thank you very much.
0:04:38 > 0:04:41- Shall we go to the office? - Can I see the next stage?- Yeah.
0:04:41 > 0:04:43- Cheers, mate.- Thank you very much.
0:04:44 > 0:04:47I'm heading upstairs to the nerve centre of the factory.
0:04:51 > 0:04:54Wow! Looks a little bit like the NASA command centre.
0:04:57 > 0:05:01These computers monitor the colossal stocks of ingredients.
0:05:03 > 0:05:07Is each one of these an actual silo?
0:05:07 > 0:05:10- Yes.- The biggest one is the flour, right?
0:05:10 > 0:05:12Yeah, which is 390 tonnes.
0:05:12 > 0:05:14Right. And that will last you how long?
0:05:14 > 0:05:18- Two days.- That's only two days' worth of biscuits?- Yeah.
0:05:20 > 0:05:22Every 24 hours,
0:05:22 > 0:05:2720 trucks arrive with ingredients from right across the country.
0:05:27 > 0:05:30For my digestives, I'm going to need oil, sugar,
0:05:30 > 0:05:33glucose, salt and syrups.
0:05:33 > 0:05:37How do you know how much you have to order for the next day?
0:05:37 > 0:05:39We don't order.
0:05:39 > 0:05:43- What happens, then?- Each one of our suppliers has access
0:05:43 > 0:05:47to see what's inside the tanks, and when they've got an empty tank,
0:05:47 > 0:05:50- they're sending a delivery. - I think that's a brilliant system.
0:05:50 > 0:05:53It's like having a little camera inside your cupboard saying,
0:05:53 > 0:05:55- "We've run out of biscuits..." - Get some more!
0:05:55 > 0:05:58And the supermarket sends the biscuits along!
0:05:58 > 0:05:59- Yeah.- Is that right?- Very true.
0:06:02 > 0:06:05An hour and a quarter after it arrived, my flour is unloaded.
0:06:06 > 0:06:08The computer screens confirm
0:06:08 > 0:06:10that everything else is ready and waiting.
0:06:12 > 0:06:16I've now got nearly all of my ingredients for my biscuit.
0:06:16 > 0:06:19However, Cherry, where's my chocolate?
0:06:22 > 0:06:27It's being prepared 200 miles away at this refinery in Manchester.
0:06:31 > 0:06:34I'm going to make a batch of chocolate for Gregg's biscuits
0:06:34 > 0:06:36with factory manager, Dee Smith.
0:06:37 > 0:06:39- Hi, Dee!- Hi, Cherry.
0:06:39 > 0:06:42- Lovely to meet you!- Welcome to Manchester.- Thank you so much!
0:06:43 > 0:06:46So, this is where you cook the chocolate?
0:06:46 > 0:06:49Well, this is where we make the chocolate.
0:06:49 > 0:06:50There's no cooking involved.
0:06:50 > 0:06:53So, it's a process of mixing, refining,
0:06:53 > 0:06:56and a very special process called conching.
0:06:56 > 0:06:58But this is no ordinary chocolate.
0:06:58 > 0:07:01No, it's a really special chocolate for coating biscuits,
0:07:01 > 0:07:04so that when you put it in your mouth, it melts.
0:07:07 > 0:07:11So, we've got 1,500 kilos of mix in here.
0:07:11 > 0:07:13And it's just about ready to discharge.
0:07:13 > 0:07:16- Oh, here we go!- Are we ready? - Something's happening!
0:07:16 > 0:07:17Oh!
0:07:17 > 0:07:19- Right, let's have a peek.- Whoa!
0:07:19 > 0:07:22- SHE YELPS - Wow!
0:07:22 > 0:07:25- It's so... Look at that! - SHE LAUGHS
0:07:26 > 0:07:29'This is a rough mix of cocoa, sugar,
0:07:29 > 0:07:32'milk powder, oil and vanilla.'
0:07:32 > 0:07:33It doesn't feel like
0:07:33 > 0:07:36it's sticking your hands into chocolate, that's for sure.
0:07:36 > 0:07:38It does remind me of something else, I'll be honest!
0:07:38 > 0:07:42It's very granulated at this stage. It's quite rough.
0:07:43 > 0:07:47Dee, that is one of the most beautiful smells on Planet Earth,
0:07:47 > 0:07:50- but I've got to say... - Smells better than it looks!
0:07:50 > 0:07:52..it smells better than it looks!
0:07:52 > 0:07:54- Can I taste it?- Yes, you can.
0:07:58 > 0:08:00It tastes like chocolate sand.
0:08:00 > 0:08:03That's a really good description, actually.
0:08:03 > 0:08:05And that's why we need to get the particle size
0:08:05 > 0:08:06much, much, much smaller.
0:08:08 > 0:08:12The sugar crystals are currently the size of the granulated sugar
0:08:12 > 0:08:14you buy in the shops.
0:08:14 > 0:08:16To make the mix smoother,
0:08:16 > 0:08:20it's dropped down 16 feet, into machines called refiners.
0:08:22 > 0:08:26This is the first stage of the refining process.
0:08:26 > 0:08:30Here, the grainy mix is crushed by a series of giant rollers
0:08:30 > 0:08:32into tiny flakes.
0:08:32 > 0:08:35And it reduces the particle size down from 1.5mm
0:08:35 > 0:08:40that we saw upstairs, down to 0.05 of a millimetre.
0:08:40 > 0:08:44That actually increases the surface area and therefore,
0:08:44 > 0:08:47it goes from becoming like a slurry and into a powder.
0:08:47 > 0:08:50The next process, called conching,
0:08:50 > 0:08:54will transform the dry powder into molten chocolate.
0:08:57 > 0:09:00OK, Cherry, this is conching.
0:09:00 > 0:09:03It is Willy Wonka! Yes!
0:09:03 > 0:09:07In here, there's six tonnes of chocolate
0:09:07 > 0:09:09and it gets mixed for six hours.
0:09:09 > 0:09:14With huge blades, almost like a Mississippi riverboat!
0:09:14 > 0:09:17Absolutely, but it's much more aggressive than that.
0:09:19 > 0:09:23Liquid cocoa butter has been added to help the chocolate
0:09:23 > 0:09:25spread evenly on top of our biscuits.
0:09:27 > 0:09:29Astonishingly, the chemistry of this process
0:09:29 > 0:09:31is still not fully understood.
0:09:33 > 0:09:35But it makes a big difference.
0:09:35 > 0:09:38The endless churning releases flavour compounds,
0:09:38 > 0:09:41making the chocolate taste rich and velvety.
0:09:43 > 0:09:46# Oh, yeah! #
0:09:46 > 0:09:50But if you beat it for too long, you get a flavour that's different.
0:09:50 > 0:09:53And that's one of the signatures of our chocolate,
0:09:53 > 0:09:56is mixing it just right to get that correct flavour
0:09:56 > 0:09:59and the correct thickness of the chocolate.
0:10:00 > 0:10:02# Beautiful! #
0:10:04 > 0:10:08After six hours, my chocolate is shiny and smooth.
0:10:09 > 0:10:11But it's not going anywhere
0:10:11 > 0:10:16until it's been thoroughly tested by refinery veterans Carla and Eva.
0:10:17 > 0:10:20Using a technique called laser diffraction,
0:10:20 > 0:10:24they fire laser beams at the particles in the chocolate
0:10:24 > 0:10:25to check they're the right size.
0:10:26 > 0:10:29But the machine doesn't get final approval.
0:10:29 > 0:10:33Carla and Eva have to conduct a chocolate taste test
0:10:33 > 0:10:34to check its consistency.
0:10:35 > 0:10:38So, what are you looking for when you test chocolate?
0:10:38 > 0:10:40Yes, we have to test the viscosity,
0:10:40 > 0:10:43so that you know that it's going to coat the biscuit correctly.
0:10:43 > 0:10:46And hold the shape of the design on the top.
0:10:46 > 0:10:48There we go.
0:10:48 > 0:10:50Oh, fresh out the conch.
0:10:50 > 0:10:54Just dip it in and try and put it in the middle of your tongue.
0:10:54 > 0:10:56- OK.- And leave it there. - SHE CHUCKLES
0:11:02 > 0:11:07That is just the most gorgeously sweet and rich and smooth chocolate.
0:11:07 > 0:11:11So, all that sugar has been refined.
0:11:11 > 0:11:12Are you not sick of chocolate?
0:11:12 > 0:11:15I'm not sick of chocolate, but I can never go to a party
0:11:15 > 0:11:16because if I see a chocolate fountain,
0:11:16 > 0:11:18it just reminds me of work.
0:11:19 > 0:11:23So, no fondue and no chocolate fountains, thank you very much.
0:11:28 > 0:11:33Now, my chocolate's ready for its 200-mile journey to London.
0:11:33 > 0:11:36To make sure it doesn't solidify in transit,
0:11:36 > 0:11:38it's pumped into a specially heated tanker.
0:11:40 > 0:11:43The lorry is specifically designed to ensure
0:11:43 > 0:11:45that the temperature's kept at 50 degrees centigrade
0:11:45 > 0:11:47for the entire journey.
0:11:47 > 0:11:51So, is the lorry like a huge hot thermos of chocolate?
0:11:52 > 0:11:55How much is the chocolate in this lorry worth?
0:11:55 > 0:11:59About £50,000 worth of chocolate in a tanker like this.
0:11:59 > 0:12:02- Liquid gold.- Yeah, absolutely.
0:12:03 > 0:12:0826 tonnes of liquid chocolate heads out on its way to the factory.
0:12:08 > 0:12:12Just one of 14 trucks making this four-hour journey every week.
0:12:16 > 0:12:18And after a trouble-free trip,
0:12:18 > 0:12:22it's ready and waiting for me in the wet ingredients area.
0:12:24 > 0:12:27Factory manager Nina Sparks is showing me round.
0:12:27 > 0:12:30Nina, this is big.
0:12:30 > 0:12:33This is, and this is where the chocolate
0:12:33 > 0:12:36comes into the liquids block.
0:12:36 > 0:12:38So, it's a big pump here,
0:12:38 > 0:12:40chocolate's connected up on the outside
0:12:40 > 0:12:43and it's pumped into one of these six tanks.
0:12:43 > 0:12:47- How much chocolate?- Each tank's probably got about 26 tonnes in.
0:12:47 > 0:12:50We can hold about 160 tonnes at any one time.
0:12:51 > 0:12:55Chocolate is the most expensive ingredient needed for my biscuits.
0:12:55 > 0:12:58It costs around £2,000 a tonne,
0:12:58 > 0:13:01so Nina and I are currently surrounded
0:13:01 > 0:13:06by about £320,000 worth of the stuff.
0:13:06 > 0:13:08I can show you the top of one, if you want to.
0:13:08 > 0:13:09I can look into a tank of chocolate?
0:13:09 > 0:13:12You can come and see 26 tonne of chocolate, Come on.
0:13:12 > 0:13:13- Has anyone ever sort of paddled in it?- No!
0:13:13 > 0:13:15Can I dunk in it, just up to my knee?
0:13:15 > 0:13:17- No, you can't.- No? Are you sure?
0:13:18 > 0:13:21Each silo is 12 metres tall
0:13:21 > 0:13:25and kept at a constant temperature of 55 degrees Celsius
0:13:25 > 0:13:28to ensure the chocolate stays liquid.
0:13:28 > 0:13:30You can't just heat it back up again?
0:13:30 > 0:13:31It would take a really long time.
0:13:31 > 0:13:34Once chocolate goes hard, it takes a lot of energy,
0:13:34 > 0:13:36a lot of heat, to get it back to being liquid again.
0:13:36 > 0:13:37Do you want to have a look in?
0:13:42 > 0:13:44Wow!
0:13:45 > 0:13:48Yep! That's where I want to go.
0:13:48 > 0:13:52- Can't I just get a ladle of it out? - No.- Why? Why can't I?
0:13:52 > 0:13:53I'm not coming out!
0:13:54 > 0:13:56I like it in here.
0:13:58 > 0:13:59In the next 24 hours,
0:13:59 > 0:14:03they'll get through over two silos' worth of liquid chocolate.
0:14:05 > 0:14:08Right, got the dry ingredients, now I've got my chocolate.
0:14:08 > 0:14:11- Can I go and make some biscuits? - Let's go.- Come on!
0:14:12 > 0:14:15I'm going to be one of the best biscuit-makers you've ever seen.
0:14:15 > 0:14:16You are!
0:14:18 > 0:14:20Next door is the mixing hall.
0:14:21 > 0:14:24Here, I'm going to make my batch of dough.
0:14:25 > 0:14:30It's a two-stage process, and the first is called creaming up.
0:14:31 > 0:14:32We've got 11 mixers up here
0:14:32 > 0:14:34and this mixer here is the one we're going to make
0:14:34 > 0:14:37- your batch of biscuits on. - Are they waiting for this now?
0:14:37 > 0:14:40- They are waiting for us. We've got to get on.- Seriously?
0:14:40 > 0:14:41We need to go and start the mixer.
0:14:41 > 0:14:43I need you to press that green button now.
0:14:43 > 0:14:46- Is that all?- Just the green button. - And that's going to make it start?
0:14:46 > 0:14:49Don't mess it up, Gregg, just the green button.
0:14:49 > 0:14:50- You want to start this, don't you?- I do.
0:14:52 > 0:14:55It's just started its process and it will be dropping
0:14:55 > 0:14:58all the different ingredients it needs into the bowl right now.
0:15:00 > 0:15:04The wet ingredients - fat, water and sugars -
0:15:04 > 0:15:08are dropped into the hopper and mixed together for 90 seconds.
0:15:15 > 0:15:19That is just like a great big mixing bowl, isn't it?
0:15:19 > 0:15:21- Same as the bowl at home.- Exactly.
0:15:21 > 0:15:23Do you know how many biscuits that will make?
0:15:23 > 0:15:27- 60,000.- 60,000 in each batch? - That's right, yeah.
0:15:27 > 0:15:30That's fantastic. Right, now what happens to it?
0:15:30 > 0:15:32Right, so, now we're ready to do our dough-up.
0:15:32 > 0:15:35- You honestly call it a dough-up? - We do.
0:15:35 > 0:15:37This is where we add our flours, so we've got white flour,
0:15:37 > 0:15:39wholemeal flour and a touch of salt.
0:15:40 > 0:15:42- Cream-up, dough-up?- Correct.
0:15:42 > 0:15:44Do you get a biscuit-up, eventually?
0:15:44 > 0:15:46Well, we hope so, yeah.
0:15:49 > 0:15:53'My flour, along with the other dry ingredients, drops down from above.
0:15:55 > 0:15:59'Another 17 minutes of mixing and my dough is done.'
0:15:59 > 0:16:01- Whay!- Yay!
0:16:01 > 0:16:04- Now, that looks like a biscuit batch.- That's right.
0:16:04 > 0:16:06So, we've got to do some checks on it first,
0:16:06 > 0:16:08so if you open the door for me.
0:16:08 > 0:16:09Right.
0:16:09 > 0:16:11Can you put the thermometer in it, please, Gregg?
0:16:11 > 0:16:14- Why?- Because if it's too cold,
0:16:14 > 0:16:16then the dough will be too crumbly
0:16:16 > 0:16:18and we won't be able to form a biscuit.
0:16:18 > 0:16:19And if it's too hot,
0:16:19 > 0:16:22it'll be too sticky and it will not run through our equipment.
0:16:22 > 0:16:26- What temperature do you want? - I want it to be between 24 and 28.
0:16:26 > 0:16:28- What is it?- 26.
0:16:28 > 0:16:29Perfect, right.
0:16:32 > 0:16:35I've now got 850 kilos of dough
0:16:35 > 0:16:38ready to turn into digestive biscuits.
0:16:40 > 0:16:43Digestive - that's quite an odd name for a biscuit, isn't it?
0:16:43 > 0:16:46Ruth has been checking out its origin.
0:16:50 > 0:16:53We all know these instantly as digestive biscuits,
0:16:53 > 0:16:55but I'm not sure that my doctor
0:16:55 > 0:16:58is going to be prescribing them any time soon.
0:16:58 > 0:17:03So, where did this association with digestion come from?
0:17:05 > 0:17:08'Medical historian Professor Louise Hill Curth...'
0:17:08 > 0:17:10Ruth! Good to see you!
0:17:10 > 0:17:12'..tells me that 500 years ago,
0:17:12 > 0:17:14'biscuits were thought of as medicine
0:17:14 > 0:17:16'and given to people who were ill.'
0:17:16 > 0:17:20So, today, you might be given something really bland
0:17:20 > 0:17:22and easy to digest.
0:17:22 > 0:17:26Well, in the Tudor period, you might be given biscuits.
0:17:26 > 0:17:29Because they were very easy to digest.
0:17:29 > 0:17:32They were very light, there wasn't much in them,
0:17:32 > 0:17:36and you could have those as part of your recuperation.
0:17:36 > 0:17:38So, have we got any sort of references
0:17:38 > 0:17:41to people eating biscuits for their health?
0:17:41 > 0:17:43Lots. Lots and lots.
0:17:44 > 0:17:47'One of them is from the mid-17th-century diarist
0:17:47 > 0:17:52'Samuel Pepys, in his entry for September 1665.'
0:17:53 > 0:17:56"Being full of wind and out of order,
0:17:56 > 0:17:58"and there called for a biscuit."
0:17:59 > 0:18:01"My digestion's all up the Swanee and..."
0:18:01 > 0:18:03- Well, wouldn't you? - "I need biscuits!"
0:18:03 > 0:18:05- Yeah!- "Bring me a biscuit!"
0:18:05 > 0:18:10And a play from 1662 promoted the medicinal properties
0:18:10 > 0:18:14of something called a Naples biscuit.
0:18:14 > 0:18:16And in the afternoon, about four or five o'clock,
0:18:16 > 0:18:20you must take "Naples biscuit dipped in Hippocras..."
0:18:20 > 0:18:24- Which is wine. - "..which helps digestion much."
0:18:25 > 0:18:29That's right, so, you dip it in wine and that helps your digestion.
0:18:29 > 0:18:31'These Naples biscuits were quite different
0:18:31 > 0:18:34'from the digestives we know today.'
0:18:34 > 0:18:38- We've got a 17th-century recipe here.- Absolutely.
0:18:38 > 0:18:41'The ingredients were exotic and expensive.'
0:18:41 > 0:18:44Take almonds, beaten very fine.
0:18:44 > 0:18:47Was that important, then, the fineness of the almond?
0:18:47 > 0:18:50Absolutely. Because you want it really easy to digest,
0:18:50 > 0:18:52so you don't want big pieces of something.
0:18:55 > 0:18:57We're now going to add wine, OK?
0:18:57 > 0:19:01- As much as we need to. - Medicinal.- Absolutely.
0:19:01 > 0:19:03- You feel much better, don't you? - I'm feeling better already.
0:19:03 > 0:19:05I knew you would.
0:19:05 > 0:19:08'Next, we add fine flour and rose water,
0:19:08 > 0:19:10'which was meant to be good for the heart.'
0:19:10 > 0:19:15The next thing we're going to put in is an entire pound of sugar.
0:19:15 > 0:19:17I mean, this is a health recipe!
0:19:17 > 0:19:20- It's packed full of alcohol and sugar!- Well, yes.
0:19:21 > 0:19:23'The final ingredient is whipped-up egg white,
0:19:23 > 0:19:25'which helps to aerate the mix.'
0:19:26 > 0:19:27According to the original recipes,
0:19:27 > 0:19:31we need to now put them into tin coffins.
0:19:31 > 0:19:34I love that word. It's the word for any pastry case at that period.
0:19:34 > 0:19:37- That's right. - Have you got any tin coffins?
0:19:37 > 0:19:41We don't have any, unfortunately, but we do have the next best thing.
0:19:45 > 0:19:48'After baking, it's time to give the Naples biscuits a try.'
0:19:51 > 0:19:53- Mmm. - SHE LAUGHS
0:19:53 > 0:19:55They are quite unique. Certainly very different
0:19:55 > 0:19:58from the sort of biscuit we would call a digestive these days.
0:19:58 > 0:20:00- They're very light, aren't they? - They are.- Yeah.
0:20:00 > 0:20:02Do you feel healthier?
0:20:04 > 0:20:08It was another 200 years before the modern digestive appeared.
0:20:09 > 0:20:12This 1829 advert in the Manchester Courier
0:20:12 > 0:20:14is one of the earliest known references
0:20:14 > 0:20:16to a biscuit with that name.
0:20:16 > 0:20:18And it says, "J Hutchinson,
0:20:18 > 0:20:22"the original introducer and sole proprietor of Abernethy's
0:20:22 > 0:20:25"celebrated digestive biscuits..."
0:20:25 > 0:20:28'Made to a similar recipe to the version we know today,
0:20:28 > 0:20:31'they were still being marketed as a health product.'
0:20:31 > 0:20:35The number of things this claims to cure is quite remarkable!
0:20:35 > 0:20:38Imagine being able to cure typhoid or scarlet fever
0:20:38 > 0:20:40by eating a biscuit!
0:20:40 > 0:20:42I mean, this is ridiculous, isn't it?
0:20:42 > 0:20:44Er, by modern standards, yeah,
0:20:44 > 0:20:47but it is very typical of the 19th century.
0:20:48 > 0:20:51When McVitie's introduced their version in 1892,
0:20:51 > 0:20:54the focus was more on the taste of the biscuit,
0:20:54 > 0:20:57rather than its perceived health benefits.
0:20:57 > 0:21:00But the name - digestive - remained.
0:21:06 > 0:21:07GREGG: An hour and a half in,
0:21:07 > 0:21:12I'm gearing up to make a super-sized batch of 60,000 biscuits.
0:21:13 > 0:21:15My dough has made it to the oven hall,
0:21:15 > 0:21:17where I'm meeting Lawrence Gathari.
0:21:17 > 0:21:20He's worked here for 38 years...
0:21:20 > 0:21:22- Hello, Gregg!- Hello, mate.
0:21:22 > 0:21:25..and knows biscuits inside out.
0:21:26 > 0:21:28Right, I'm ready to make biscuits.
0:21:28 > 0:21:30What happens down here?
0:21:30 > 0:21:34Well, down here is the area where we mould the biscuits.
0:21:34 > 0:21:35Why do you keep looking up there?
0:21:35 > 0:21:37Because in a minute, I want you to get up there
0:21:37 > 0:21:40- and tell me what you see. - Really?- Yes.- Up?
0:21:41 > 0:21:44- If I'm not back, tell me mum I love her.- OK, I will.
0:21:47 > 0:21:49It's not what I expected.
0:21:49 > 0:21:51It's coming down in great clumps,
0:21:51 > 0:21:55pretty much like the way snow falls off the roof of your shed, you know?
0:21:55 > 0:21:59Well, it's the type of dough that's easily broken up.
0:21:59 > 0:22:02There's quite a loose consistency to the dough.
0:22:02 > 0:22:06So what we need to do is break it up into small enough clumps,
0:22:06 > 0:22:09so it can be evenly distributed into the small hopper.
0:22:13 > 0:22:16'The machine that does this is called the kibbler.
0:22:19 > 0:22:23'Spinning blades shred the dough and fling the pieces onto a conveyor.
0:22:23 > 0:22:27'They are now only moments away from their biscuit-shaped destiny.'
0:22:27 > 0:22:30I can see the dough's coming down there.
0:22:30 > 0:22:33It's then dropping between two rollers.
0:22:33 > 0:22:35The front roller that you can see there
0:22:35 > 0:22:37is what we call the moulding roller,
0:22:37 > 0:22:40which has the shape of the biscuit cut in silhouette.
0:22:40 > 0:22:45I can see this mould shining in a little bit of light.
0:22:45 > 0:22:47- Can I get a closer look at that? - Well, we've got one over there.
0:22:47 > 0:22:49- Shall we go and see it? - Yeah, yeah, yeah.
0:22:51 > 0:22:53That is a beautiful thing!
0:22:55 > 0:22:57I can see exactly how that works now.
0:22:57 > 0:23:00As that turns, the dough is pushed onto it
0:23:00 > 0:23:03and that then is cutting the shape
0:23:03 > 0:23:05and it's imprinting the name and the holes.
0:23:05 > 0:23:07Absolutely right. Well done.
0:23:07 > 0:23:09It's very attractive and rather clever.
0:23:09 > 0:23:11- Not unlike yourself, mate. - Thank you, Gregg.
0:23:28 > 0:23:31I'm surprised that you mould these biscuits and don't cut them.
0:23:31 > 0:23:34At home, you would have a big sheet of pastry
0:23:34 > 0:23:37and you would cut each biscuit from it.
0:23:37 > 0:23:40Well, here, Gregg, we're making so many biscuits,
0:23:40 > 0:23:43this is the only way that we can mass-produce them.
0:23:43 > 0:23:47Do you know how many biscuits are passing our nose every minute?
0:23:47 > 0:23:49- Over 3,000.- Is it?
0:23:51 > 0:23:53THEY CACKLE
0:23:54 > 0:23:57This factory runs 24 hours a day,
0:23:57 > 0:24:00stamping out a never-ending river of biscuits.
0:24:01 > 0:24:04At this rate, it'll take less than 20 minutes
0:24:04 > 0:24:07to mould my batch of 60,000.
0:24:07 > 0:24:09What happens to all the little extra bits?
0:24:09 > 0:24:13There's a scraper that scrapes the excess dough off them
0:24:13 > 0:24:16and it drops into this conveyor by my feet
0:24:16 > 0:24:19and it runs into this spiral and fed back in.
0:24:21 > 0:24:23Hang on. Things go down a spiral.
0:24:23 > 0:24:25These look like they're going up a spiral.
0:24:25 > 0:24:26They're designed in a way
0:24:26 > 0:24:30that it vibrates to send the product upwards.
0:24:30 > 0:24:31That's defying gravity!
0:24:31 > 0:24:34- There you go, - Things don't go up a spiral!
0:24:34 > 0:24:35It's amazing what you can do here.
0:24:42 > 0:24:47So, obviously, this roller is a crucial bit of biscuit-making kit.
0:24:47 > 0:24:52Chances are, this one started life in Wigan, with a man called Alan.
0:24:52 > 0:24:54Cherry went to meet him.
0:24:54 > 0:24:57Hi, excuse me. I'm looking for Alan.
0:24:58 > 0:25:00- Alan Long?- Yeah.- He's in unit 5A.
0:25:08 > 0:25:10- Hi, Alan!- Hello, Cherry.
0:25:10 > 0:25:12- Nice to meet you.- Nice to meet you.
0:25:12 > 0:25:14'Alan Long creates the rollers
0:25:14 > 0:25:16'used in most of Britain's biscuit factories.'
0:25:16 > 0:25:19Where is everybody?
0:25:19 > 0:25:22There's just me. Everything here, I do.
0:25:22 > 0:25:24So, where do we start?
0:25:24 > 0:25:25We're going to get a blank roller
0:25:25 > 0:25:27and we're going to turn it into a biscuit roller.
0:25:27 > 0:25:29All right, let's get cracking.
0:25:30 > 0:25:32His one-man manufacturing process
0:25:32 > 0:25:35begins with a shiny roller of bronze.
0:25:35 > 0:25:40It weighs 400 kilos and costs up to £5,000.
0:25:40 > 0:25:43Bronze has been the alloy of choice for artists and sculptors
0:25:43 > 0:25:47for millennia, and it turns out it's a favourite of Alan's too.
0:25:49 > 0:25:53Why on earth do you use such a luxurious material?
0:25:53 > 0:25:55Well, the great thing about the bronze
0:25:55 > 0:25:58is it's food-approved, lead-free and also it's very nice to machine.
0:25:58 > 0:26:02I really love that this is how biscuits start their life.
0:26:02 > 0:26:03It's a thing of beauty.
0:26:03 > 0:26:07At the moment. We're going to make it look even more beautiful.
0:26:07 > 0:26:10'Today, Alan's making a mould for shortbread biscuits.'
0:26:10 > 0:26:13- Up?- Yes, please.- Up is up?
0:26:13 > 0:26:17'And my first job is to help winch the bronze roller
0:26:17 > 0:26:19'into the specialist milling machine.'
0:26:19 > 0:26:21Down, down, down.
0:26:24 > 0:26:26- Is that right?- Yeah, perfect.
0:26:26 > 0:26:28Who knew this is how biscuits start?
0:26:29 > 0:26:31'To avoid wonky biscuits,
0:26:31 > 0:26:35'the roller must be perfectly level before the machine starts cutting.
0:26:35 > 0:26:39'This measuring tool can detect minute changes
0:26:39 > 0:26:40'to the roller's alignment.
0:26:40 > 0:26:43'If the needle moves, there's a problem.'
0:26:43 > 0:26:46- Perfect.- It's not moving, is it? - Didn't move, did it?- It's perfect.
0:26:46 > 0:26:49- That did not move at all. - Nice and flat. It did not move.
0:26:49 > 0:26:52This is such an exercise of precision.
0:26:52 > 0:26:56There's going to be no uneven biscuits on Alan's watch.
0:26:57 > 0:27:00'The roller's in place, and in the office,
0:27:00 > 0:27:03'I get to see the shortbread petticoat tail design
0:27:03 > 0:27:05'we'll be cutting into it.'
0:27:05 > 0:27:08So, that's a mock-up of what will happen?
0:27:08 > 0:27:11This is a simulation of what we see on the machine.
0:27:11 > 0:27:14The tool will move in that way and cut out
0:27:14 > 0:27:17- that imprint into the bronze? - Exactly that tool path, yeah.
0:27:17 > 0:27:20I mean, that is so intricate.
0:27:20 > 0:27:23So, how do you design a biscuit?
0:27:23 > 0:27:25Everything's drawn up here on this CAD system.
0:27:25 > 0:27:29This one, originally, the customer told me he wanted six segments,
0:27:29 > 0:27:31as you can see, with a random docker pattern
0:27:31 > 0:27:35and a border outline with the little flutes around.
0:27:35 > 0:27:37How did you learn to do this?
0:27:37 > 0:27:39Originally, I was in the aerospace industry.
0:27:39 > 0:27:41I then decided to use that technology
0:27:41 > 0:27:45in the biscuit industry to make that a more modern process.
0:27:45 > 0:27:48Could you ever have guessed this is what you would end up doing?
0:27:48 > 0:27:50Not at the time, no!
0:27:50 > 0:27:53'Alan sends the design over to the milling machine
0:27:53 > 0:27:55'and prepares a new drillbit.'
0:27:56 > 0:27:58OK, Cherry, it's ready to go.
0:28:00 > 0:28:02Turn the feed up, it's 100%.
0:28:02 > 0:28:06- 100%?- Come on, memory. - Memory.- Search.
0:28:06 > 0:28:09- Search.- Programme 4.- Yes.
0:28:09 > 0:28:11- Cycle start. - Cycle start. Stand by!
0:28:16 > 0:28:18Whoa!
0:28:21 > 0:28:26This tungsten carbide drill cuts into the bronze.
0:28:26 > 0:28:30It's accurate to within 0.03 of a millimetre.
0:28:34 > 0:28:37Wow, that looks so cool!
0:28:41 > 0:28:46'It can take up to an hour to engrave a single biscuit design.'
0:28:49 > 0:28:52- Do you want to have a look at it? - So badly!
0:28:53 > 0:28:55Oh, my goodness!
0:28:55 > 0:28:57So, there's your first petticoat tail done.
0:28:57 > 0:29:00- It's unnecessarily beautiful. - It's great, isn't it?
0:29:00 > 0:29:03Considering it's just going to imprint a biscuit.
0:29:03 > 0:29:05- It is, yeah.- It's a work of art! - Do you like it?
0:29:05 > 0:29:08It will go into a machine, it'll make lots and lots of biscuits.
0:29:08 > 0:29:12Engraving the 40 moulds wrapped around this roller
0:29:12 > 0:29:14will take 40 hours.
0:29:14 > 0:29:18Some intricate biscuit patterns, like this custard cream,
0:29:18 > 0:29:20can take five days to complete.
0:29:22 > 0:29:24- I'm going to leave you to it.- Right.
0:29:24 > 0:29:28But before I go, can I take a souvenir, to see if it works?
0:29:28 > 0:29:30- Of course you can.- Hee-hee-hee!
0:29:30 > 0:29:32Here we go, the moment of truth.
0:29:33 > 0:29:36Look! That is...
0:29:36 > 0:29:38- Beautiful.- Beautiful.
0:29:38 > 0:29:42- I love it. Thank you so much. - No problem.
0:29:42 > 0:29:45'Each finished roller has a lifespan of up to two years,
0:29:45 > 0:29:50'in which time it could mould more than 3 billion biscuits.'
0:29:50 > 0:29:53Next time you crack open the biscuit tin,
0:29:53 > 0:29:55don't forget to take a moment
0:29:55 > 0:29:57to appreciate the artistry and technology
0:29:57 > 0:29:59that's gone into that design.
0:30:10 > 0:30:11Over two hours in,
0:30:11 > 0:30:14and I'm chasing my batch of digestives
0:30:14 > 0:30:16on their way to a hot date.
0:30:17 > 0:30:20So, Gregg, this is where the biscuits enter the oven
0:30:20 > 0:30:21on their long journey.
0:30:21 > 0:30:23- How long do they bake for? - Six minutes.
0:30:24 > 0:30:26Through the whole strip of these ovens?
0:30:26 > 0:30:27The whole strip of these ovens.
0:30:27 > 0:30:31The oven's 80 metres long and it's divided into four zones,
0:30:31 > 0:30:35because we want certain things to happen at certain stages.
0:30:36 > 0:30:39'They bake so many biscuits here, they have 11 ovens,
0:30:39 > 0:30:41'each one using as much gas in a day
0:30:41 > 0:30:44'as an average household uses in a year.'
0:30:44 > 0:30:46Gregg, this is the first zone of the oven...
0:30:48 > 0:30:50..and in this zone, what we want to do
0:30:50 > 0:30:53is start the biscuits rising and we want to start releasing
0:30:53 > 0:30:56some of the moisture off from the biscuit.
0:30:56 > 0:30:59- So, what temperature is this one? - This is 180 degrees.
0:30:59 > 0:31:02- Is it?- We don't want it too hot because if it's too hot,
0:31:02 > 0:31:04it will coat the biscuit,
0:31:04 > 0:31:07it'll seal in the moisture and it will just break apart.
0:31:07 > 0:31:09- Can we have a look inside? - We will.
0:31:12 > 0:31:16Right. They have risen probably twice their size.
0:31:16 > 0:31:17They have.
0:31:21 > 0:31:23The next zone ramps up the temperature
0:31:23 > 0:31:26to more than 250 degrees Celsius.
0:31:27 > 0:31:31The high heat forces the remaining moisture out through the 18 holes
0:31:31 > 0:31:34stamped into the top of the biscuits.
0:31:34 > 0:31:37So, up here, the biscuits have fully risen,
0:31:37 > 0:31:40we've baked all the moisture out to within spec
0:31:40 > 0:31:42and we're looking at 2.2%.
0:31:42 > 0:31:45And the biscuits are starting to colour.
0:31:45 > 0:31:48- They most certainly are. Fantastic. Can I have a smell?- Course you can.
0:31:48 > 0:31:50Mind you don't burn yourself!
0:31:51 > 0:31:53That's smelling like biscuits!
0:31:55 > 0:31:59The conveyor runs at just under one mile per hour...
0:32:00 > 0:32:03..giving each digestive precisely the same time in the oven.
0:32:05 > 0:32:10And that is just a wonderful, constant floating river of biscuits.
0:32:10 > 0:32:11It is.
0:32:11 > 0:32:14# When ol' man river... #
0:32:14 > 0:32:18And now the river takes a surprising diversion.
0:32:19 > 0:32:21Because the modern production line
0:32:21 > 0:32:23has reached the walls of the old factory,
0:32:23 > 0:32:26it needs to make a 180-degree turn.
0:32:27 > 0:32:29# ..just keeps rollin' #
0:32:29 > 0:32:34It's called the Power Bend, and it's been here for almost 30 years.
0:32:34 > 0:32:37- # Doo-doo-do! - Keeps on rollin'... #
0:32:37 > 0:32:38Biscuits on the outside of the curve
0:32:38 > 0:32:42travel three times faster than those on the inside.
0:32:44 > 0:32:46Do you think we've made the perfect biscuit?
0:32:46 > 0:32:48I don't know, I haven't eaten one. They look good.
0:32:49 > 0:32:52'My biscuits have made it through the oven,
0:32:52 > 0:32:54'but now face a battery of tests.'
0:32:56 > 0:32:59We're going to take a biscuit off the line and measure the diameter.
0:33:00 > 0:33:04'If they're the wrong size, they won't fit in the packets
0:33:04 > 0:33:08'and the whole batch will be recycled as animal food.'
0:33:08 > 0:33:11If it fits in there, the biscuit, the diameter's too small.
0:33:14 > 0:33:15No!
0:33:15 > 0:33:18And if it fits in there, it's just right.
0:33:21 > 0:33:24That is beautifully simple.
0:33:24 > 0:33:27I like that. Like that. Right, now what?
0:33:27 > 0:33:29I want you to take nine biscuits.
0:33:29 > 0:33:30I've got one, right.
0:33:33 > 0:33:34Whoa, they're hot!
0:33:34 > 0:33:36Add them to the nine biscuits
0:33:36 > 0:33:38that we got from the other side earlier...
0:33:38 > 0:33:41- Making sure the oven's cooking them evenly?- That's it.
0:33:41 > 0:33:43'This is the stack height test,
0:33:43 > 0:33:46'which checks the biscuits are the correct thickness.'
0:33:46 > 0:33:49What length should the 18 biscuits be?
0:33:49 > 0:33:52- We're looking at 130 millimetres.- 130.
0:33:54 > 0:33:57That's just short of 130.
0:33:57 > 0:34:00We allow plus and minus one millimetre.
0:34:00 > 0:34:03- Right.- So, if it's 129, it's spot on.
0:34:03 > 0:34:05Yeah, you're there. You're there.
0:34:07 > 0:34:12So far, my biscuits are doing OK, measuring up at 7.2mm each.
0:34:13 > 0:34:15They're up to standard and ready to move on.
0:34:18 > 0:34:21Do you know what you need, don't you? I think.
0:34:21 > 0:34:25You need, like, a quality taster, someone with an expert palate.
0:34:27 > 0:34:29Exciting moment coming up!
0:34:29 > 0:34:32It's almost time to put the chocolate on my biscuits.
0:34:32 > 0:34:35But as Ruth's been discovering, historically,
0:34:35 > 0:34:38biscuits were more about survival than pleasure.
0:34:40 > 0:34:43A certain town in Berkshire was at the heart of it all.
0:34:44 > 0:34:46100 years ago, Reading was home
0:34:46 > 0:34:51to the world's biggest and most famous biscuit manufacturer,
0:34:51 > 0:34:52Huntley & Palmers.
0:34:54 > 0:34:59The town was dominated by the 24-acre mega-factory,
0:34:59 > 0:35:03that churned out more than 400 different types of biscuits.
0:35:04 > 0:35:07But they became notorious for just one of them.
0:35:08 > 0:35:11'I've come to Reading Museum to meet curator Brendan Carr...'
0:35:11 > 0:35:14Nice to meet you!
0:35:14 > 0:35:16'..who has some examples of the original biscuits
0:35:16 > 0:35:19'that gave the company a bad press.'
0:35:19 > 0:35:20Oh, wow!
0:35:20 > 0:35:25Now, they look like a very plain sort of biscuit!
0:35:26 > 0:35:27That's hardtack biscuit.
0:35:27 > 0:35:30What exactly is hardtack?
0:35:30 > 0:35:34Well, hardtack is just a straightforward recipe -
0:35:34 > 0:35:38it's basically flour and water, a little pinch of salt.
0:35:38 > 0:35:41These simple biscuits were easy to transport.
0:35:41 > 0:35:45So, a good source of nutrition for adventurers and the military.
0:35:51 > 0:35:54Captain Scott took Huntley & Palmers hardtack biscuits
0:35:54 > 0:35:56to the South Pole in 1910.
0:36:01 > 0:36:04Two years later, the company was the natural choice
0:36:04 > 0:36:07to manufacture and supply the biscuit rations
0:36:07 > 0:36:10issued to British soldiers in World War I.
0:36:13 > 0:36:15I can see the word "army" printed here -
0:36:15 > 0:36:18"Huntley, Palmers, Army Number Four."
0:36:18 > 0:36:19Precisely, yeah.
0:36:19 > 0:36:22There were different varieties of ration biscuit.
0:36:22 > 0:36:25When people said to you, "Your rations will be biscuits,"
0:36:25 > 0:36:27in your head, you'd have been thinking of
0:36:27 > 0:36:28the biscuits you'd had at home.
0:36:28 > 0:36:31You'd be thinking of things like bourbon creams.
0:36:32 > 0:36:34You know, rich tea biscuits,
0:36:34 > 0:36:36and then you're suddenly faced with that.
0:36:36 > 0:36:39Exactly. But the British Army had to get the men fed,
0:36:39 > 0:36:42so this was like a replacement for the bread
0:36:42 > 0:36:44that the working classes would have been used to.
0:36:44 > 0:36:46And typically, what would happen is you would break it up
0:36:46 > 0:36:49with a bit of condensed milk, maybe a bit of jam if you're lucky,
0:36:49 > 0:36:52stir it up and make a bit of porridge for yourself.
0:36:52 > 0:36:55So, you wouldn't take it, dunk it in your tea and go, "Oh, yum, yum."
0:36:55 > 0:36:57No. It's quite far removed from that.
0:36:58 > 0:37:02Five million British Tommies were supplied with these biscuits.
0:37:02 > 0:37:04But they weren't exactly popular
0:37:04 > 0:37:08and the soldiers found inventive uses for their uneaten rations.
0:37:08 > 0:37:10Soldiers used to take these biscuits
0:37:10 > 0:37:14and fashion them into a little bit of, sort of, trench art.
0:37:14 > 0:37:18These have survived because they were sent home as souvenirs.
0:37:18 > 0:37:21"Have gone on hunger strike. Reason attached.
0:37:21 > 0:37:23"Mind your toes." SHE LAUGHS
0:37:27 > 0:37:29These biscuits were so disliked,
0:37:29 > 0:37:33they became a common topic for soldiers writing home.
0:37:34 > 0:37:36- Hello. Nice to meet you. - Lovely to meet you.
0:37:36 > 0:37:41Rhys David has some letters his father sent from the Front in 1915.
0:37:42 > 0:37:46He signed up as a very young man, on his 17th birthday,
0:37:46 > 0:37:49and from there he was shipped out to Gallipoli later that year.
0:37:49 > 0:37:52So, he was definitely one of those who was supplied
0:37:52 > 0:37:54with Huntley and Palmers biscuits.
0:37:54 > 0:37:56Yes, he writes about the biscuits
0:37:56 > 0:38:00and indicates that he wasn't very happy with them.
0:38:00 > 0:38:02He calls them "those blamed biscuits".
0:38:02 > 0:38:05In fact, he refers to the problems faced by soldiers
0:38:05 > 0:38:07who'd lost their teeth.
0:38:07 > 0:38:09I can quote to you from this.
0:38:09 > 0:38:13"We sure have had our fair share of them hateful H&Ps..."
0:38:13 > 0:38:15Huntley and Palmers.
0:38:15 > 0:38:17"Jolly glad I've got a decent lot of ivories to tackle them
0:38:17 > 0:38:21"because fellows with false 'uns don't half cop it.
0:38:21 > 0:38:24"Blooming near starved and got to break 'em up with pliers
0:38:24 > 0:38:27- "to nibble at 'em." - Oh, my goodness!
0:38:30 > 0:38:33But just how bad were these hardtack biscuits?
0:38:33 > 0:38:38As a surprise for Rhys, I've got some, made to the original recipe.
0:38:38 > 0:38:42- Would you like to try a hardtack biscuit?- Oh, thank you very much.
0:38:42 > 0:38:44- Not 100 years old? - Not 100 years old!
0:38:48 > 0:38:50I mean, they're all right, aren't they?
0:38:50 > 0:38:52They're not exciting, but they're OK.
0:38:52 > 0:38:55If I hadn't eaten for a few days and I was presented with one of these,
0:38:55 > 0:38:56I wouldn't be too upset.
0:38:56 > 0:39:00But I think if I was presented with these for several days in a row,
0:39:00 > 0:39:03- then I would get pretty cheesed off. - That was all you were getting.
0:39:03 > 0:39:06- Day after day, yeah. Not horrible.- They're not horrible
0:39:06 > 0:39:08but I think I'll still go for rich teas!
0:39:08 > 0:39:09SHE LAUGHS
0:39:16 > 0:39:19GREGG: At the factory, my 60,000 digestives
0:39:19 > 0:39:21have been baked to perfection.
0:39:21 > 0:39:24And now there's just one ingredient missing.
0:39:25 > 0:39:29Here, Gregg, the biscuits are on their journey from the oven.
0:39:29 > 0:39:33They're going to travel half a kilometre to the enrober.
0:39:33 > 0:39:35- Enrober?- Enrober.
0:39:35 > 0:39:38That's the machine that puts chocolate onto the biscuit.
0:39:38 > 0:39:41That's my sort of machine, that is, sir, my sort of machine.
0:39:44 > 0:39:47This epic 500 metre journey
0:39:47 > 0:39:51is an essential part of the manufacturing process.
0:39:51 > 0:39:55As they saunter along at a sedate 25 metres a minute,
0:39:55 > 0:39:57my biscuits are gradually cooling down,
0:39:57 > 0:40:02from 90 degrees Celsius when they leave the oven, to under 30.
0:40:02 > 0:40:05This means that when the chocolate is applied,
0:40:05 > 0:40:08they'll be the perfect temperature for it to solidify.
0:40:09 > 0:40:12We want to check that the temperature of the biscuit is correct.
0:40:12 > 0:40:16Lawrence, how do you take the temperature of a biscuit?
0:40:16 > 0:40:18And what do you do if it's got a cold?
0:40:19 > 0:40:21Give it an aspirin!
0:40:21 > 0:40:22Right, go on, show me.
0:40:22 > 0:40:24Pick a biscuit up.
0:40:25 > 0:40:26And...
0:40:26 > 0:40:29- Oh, right. - ..fire this thermometer at it.
0:40:31 > 0:40:34- Where, there? - Yeah, press the trigger.
0:40:34 > 0:40:36- What have we got?- 25.2.
0:40:36 > 0:40:38- And what do you want? - Between 24 and 28.
0:40:42 > 0:40:44My batch has nailed yet another test.
0:40:46 > 0:40:47But before we put chocolate on them...
0:40:47 > 0:40:50Oh, shut up! That's got to be, that's got to be it now?!
0:40:52 > 0:40:55It turns out the chocolate isn't ready.
0:40:55 > 0:40:58One final chemical transformation is required
0:40:58 > 0:41:01before it's good enough to grace my biscuits.
0:41:02 > 0:41:06We've got to make sure the chocolate is properly tempered.
0:41:06 > 0:41:08Can I confess something to you? I'm supposed to be a food expert,
0:41:08 > 0:41:11I don't actually know what tempering chocolate means.
0:41:11 > 0:41:14Have you ever seen a chocolatier when they take some chocolate
0:41:14 > 0:41:16- and they pour it onto a slab of marble?- Yeah, yeah.
0:41:16 > 0:41:20And with a palette knife, they move it around.
0:41:20 > 0:41:22And what they're doing there is what this machine does,
0:41:22 > 0:41:24but on a massive scale.
0:41:24 > 0:41:26There's the chocolate coming in...
0:41:26 > 0:41:28- Is that that brown line? - That's that brown line.
0:41:28 > 0:41:30- Not very original, is it?! - No, not really!
0:41:30 > 0:41:33And it's slowly getting the right crystals
0:41:33 > 0:41:36and getting the chocolate at the right temperature.
0:41:36 > 0:41:41The tempering tube scrapes chocolate over a series of plates,
0:41:41 > 0:41:46reducing and regulating the size of the cocoa butter crystals.
0:41:46 > 0:41:50What would the chocolate be like if it wasn't tempered?
0:41:50 > 0:41:52Well, we've got two biscuits here to show you, Gregg.
0:41:52 > 0:41:57This is one that was just coated with the untempered chocolate.
0:41:57 > 0:42:02It's dull, it melts very easy in the hand.
0:42:02 > 0:42:05It looks grainy. That does look like someone's scraped mud on it.
0:42:05 > 0:42:07And it's got no sheen.
0:42:07 > 0:42:11- Chocolate is a complicated issue, isn't it?- It's a science.
0:42:12 > 0:42:14- It's easier eating it.- I know.
0:42:15 > 0:42:19Makeover complete, the chocolate's ready for its big moment.
0:42:21 > 0:42:24I've seen the ingredients come in, I've seen you bake a biscuit,
0:42:24 > 0:42:28I've seen you test its size, I've even seen you take its temperature,
0:42:28 > 0:42:30I know how the chocolate works.
0:42:30 > 0:42:34Can I now please have some chocolate on my biscuit, Lawrence?!
0:42:34 > 0:42:35Come on, then, let's have a look.
0:42:35 > 0:42:37- Are we finally going to get it? - We are.
0:42:41 > 0:42:46So here, Gregg, the chocolate comes from the tempering tube,
0:42:46 > 0:42:48and we form a river of chocolate.
0:42:52 > 0:42:55This process is known as enrobing,
0:42:55 > 0:42:57a posh name for putting the chocolate on.
0:42:59 > 0:43:01I don't really get it, where's the chocolate?
0:43:01 > 0:43:04The chocolate is there, that is a river, that's a surge of chocolate.
0:43:04 > 0:43:07Oh, I see. The biscuits are coming over,
0:43:07 > 0:43:09they're sitting on little metal rafts.
0:43:09 > 0:43:12I would've expected the chocolate to be put on the top of the biscuit,
0:43:12 > 0:43:15- not the bottom.- We wouldn't be able to get them on quick enough,
0:43:15 > 0:43:19and we only want to coat part of the biscuit.
0:43:19 > 0:43:21I'll take a biscuit off there.
0:43:21 > 0:43:25It's only that very top part that's got the chocolate on.
0:43:25 > 0:43:28If it was poured on, it would completely cover...
0:43:28 > 0:43:32- Oh, I see, it can't come down the sides?- It can't come down the sides.
0:43:32 > 0:43:34Is that what's making the ripple effect?
0:43:34 > 0:43:36That's the first part of the ripple effect.
0:43:39 > 0:43:41The metal wires of the conveyor
0:43:41 > 0:43:45press a set of horizontal lines into the chocolate.
0:43:47 > 0:43:49The biscuits travel on down the rapids
0:43:49 > 0:43:52towards a set of vertical rollers
0:43:52 > 0:43:56which imprint another set of lines at right angles to the first.
0:43:58 > 0:44:02And it's this that creates the distinctive crosshatched pattern.
0:44:03 > 0:44:06I'm getting it. They're falling over it, really, aren't they?
0:44:06 > 0:44:10- They are.- It's a constant waterfall of chocolate biscuits.
0:44:14 > 0:44:19As they cool down to 17 degrees Celsius, the chocolate solidifies
0:44:19 > 0:44:22on what I now know is the bottom of the biscuits.
0:44:24 > 0:44:27For some of us, the perfect accompaniment to these biscuits
0:44:27 > 0:44:29is a hot drink to dunk them in.
0:44:29 > 0:44:32For others, that's a horrifying idea.
0:44:32 > 0:44:35Well, to dunk or not to dunk?
0:44:35 > 0:44:36That is the question.
0:44:39 > 0:44:43Cherry headed to Nottingham in search of the definitive answer.
0:44:43 > 0:44:44Excuse me, excuse me, excuse me.
0:44:44 > 0:44:47Can I ask you a question? Are you a dunker or not a dunker?
0:44:47 > 0:44:49Dunker or not a dunker?
0:44:49 > 0:44:50You don't drink tea?
0:44:50 > 0:44:51Not a dunker. Tea?
0:44:51 > 0:44:54Coffee, interesting. All right.
0:44:54 > 0:44:56Are you a dunker or not a dunker?
0:44:58 > 0:44:59So I would say at the moment
0:44:59 > 0:45:03Nottingham is 50-50 dunker to non-dunker. Excuse me!
0:45:05 > 0:45:07Does that upset you, the idea of it going in there
0:45:07 > 0:45:09and getting all soggy?
0:45:09 > 0:45:11Dunky-dunk, dunky-dunk...
0:45:11 > 0:45:13I love to dunk.
0:45:15 > 0:45:17But I want to find out with real science
0:45:17 > 0:45:21whether dunking really is the right way to eat a biscuit.
0:45:23 > 0:45:27I'm hoping to find the answer at the University of Nottingham,
0:45:27 > 0:45:28where Dr Ian Fisk...
0:45:28 > 0:45:30Hi, Ian, nice to meet you.
0:45:30 > 0:45:35..is going to let me play with his state-of-the-art robot nose.
0:45:35 > 0:45:37What we're going to do today is take the biscuits,
0:45:37 > 0:45:40chew them and look at the release of aroma compounds into your nose.
0:45:40 > 0:45:42And then we're going to take the same biscuit,
0:45:42 > 0:45:45we're going to dunk it and see if the aroma release is different.
0:45:46 > 0:45:51Every time we eat food, smells, or aromas, are released into our noses.
0:45:51 > 0:45:54It's a vital part of how we taste things,
0:45:54 > 0:45:57and Ian's machine is so sensitive,
0:45:57 > 0:45:59it can detect a single aroma particle
0:45:59 > 0:46:02in 1 trillion particles of air.
0:46:02 > 0:46:05So you'll be able to tell whether the taste is better
0:46:05 > 0:46:08with or without tea?
0:46:08 > 0:46:09- Let's find out.- OK.
0:46:09 > 0:46:10So if you want to take a seat,
0:46:10 > 0:46:13this probe is going to go slightly up your nose.
0:46:13 > 0:46:14OK.
0:46:18 > 0:46:19So, breathe quite confidently.
0:46:19 > 0:46:22It's just a regular day at the office.
0:46:24 > 0:46:27This is not a comfortable biscuit-eating experience!
0:46:29 > 0:46:32Next, it's time to test a dunked biscuit.
0:46:32 > 0:46:37Will the robot nose detect more aroma particles or less?
0:46:37 > 0:46:41This is a big, big moment for biscuits and tea.
0:46:41 > 0:46:43All right, here we go. Dunking.
0:46:45 > 0:46:47- I would say that's... - SHE GASPS
0:46:51 > 0:46:56- Do they taste different? - To me, it definitely tastes better.
0:46:56 > 0:47:00I can taste the kind of nuttiness and the sweetness better.
0:47:00 > 0:47:02But does science agree?
0:47:02 > 0:47:04- Let's have a look at the data.- OK.
0:47:05 > 0:47:08So, the trace on the left is the biscuit as you ate it normally.
0:47:08 > 0:47:11The trace on the right is when you chewed it
0:47:11 > 0:47:12after it's been dunked.
0:47:12 > 0:47:15And you can see here the peak is twice as large.
0:47:15 > 0:47:18So it's not just a bit better, it's twice as good?
0:47:18 > 0:47:23- Yes.- So are you saying that biscuits do taste better
0:47:23 > 0:47:26- when they've been dunked? - That's true.
0:47:26 > 0:47:31So why does dunking a biscuit into tea make it more flavourful?
0:47:31 > 0:47:34The aroma compounds and taste compounds can diffuse out
0:47:34 > 0:47:36to the mouth and the nose much more efficiently.
0:47:36 > 0:47:39So it's not that it changes the taste of the biscuit,
0:47:39 > 0:47:45it just allows you to taste it faster and more intensely?
0:47:45 > 0:47:47- Yes.- Science has spoken!
0:47:47 > 0:47:50Dunkers are the winners!
0:47:50 > 0:47:54So, tea definitely improves the flavour of a biscuit
0:47:54 > 0:47:58but could other liquids be even better for dunking?
0:47:58 > 0:48:01Time to take this experiment to the streets.
0:48:01 > 0:48:02So, it's a very simple game.
0:48:02 > 0:48:04All you need to do is take a biscuit...
0:48:04 > 0:48:08- Yeah.- ..dunk it, and tell us which of them you prefer.
0:48:08 > 0:48:09All right, sound.
0:48:09 > 0:48:12In the green mug, we've got tea.
0:48:12 > 0:48:14In the blue, we've got coffee.
0:48:14 > 0:48:16And in the red is hot milk.
0:48:17 > 0:48:18Give it a nice dunk.
0:48:20 > 0:48:21Solid dunk, there.
0:48:23 > 0:48:24Right, have a little nibble.
0:48:27 > 0:48:30- Definitely the green one. - Definitely green?
0:48:30 > 0:48:31That's tea.
0:48:31 > 0:48:33- You prefer coffee?- Every day.
0:48:33 > 0:48:36- I'd say coffee. - Which is your favourite?
0:48:36 > 0:48:37- Tea!- Oh, yay!
0:48:37 > 0:48:40- This one.- Tea was your favourite. - Mm-hm.
0:48:40 > 0:48:42- Tea.- Tea?- Every time, tea.
0:48:42 > 0:48:44- Every time?- Every time.
0:48:44 > 0:48:47- That one.- Are you a coffee dunker? - All the time.
0:48:47 > 0:48:49- I think it's the coffee. - You like the coffee?
0:48:49 > 0:48:52People just not dunking in the milk.
0:48:52 > 0:48:53They're not feeling the milk.
0:48:53 > 0:48:55Which is your favourite?
0:48:55 > 0:48:57- Milk.- Milk!- Yeah.
0:48:59 > 0:49:00OK, it's neck and neck.
0:49:00 > 0:49:04Coffee is on four, tea is on four, milk is on one.
0:49:04 > 0:49:05So this is the decider.
0:49:05 > 0:49:09This is all down to a man called Bruce.
0:49:14 > 0:49:16Are you an experienced biscuit dunker?
0:49:16 > 0:49:19I love dunking biscuits. Yeah.
0:49:26 > 0:49:27This one.
0:49:27 > 0:49:31- So, just to confirm, which is your favourite dunking drink?- Tea.
0:49:31 > 0:49:33- Tea!- Tea.
0:49:33 > 0:49:36- Absolutely in the tea? - Absolutely, 100%.
0:49:36 > 0:49:38So they're like the perfect partnership?
0:49:38 > 0:49:41Absolutely, they go together like egg and bacon or...
0:49:41 > 0:49:43- Jelly and ice cream.- Fish and chips.
0:49:43 > 0:49:45- Cats and dogs.- Jelly and ice cream, cats and dogs.
0:49:45 > 0:49:46Honestly, that's the one.
0:49:46 > 0:49:50So the people of Nottingham have decided.
0:49:50 > 0:49:52Tea is the best brew for dunking,
0:49:52 > 0:49:54but does science agree?
0:49:54 > 0:49:58Ian has the results from the same test run in the lab.
0:49:58 > 0:50:01Coffee's not far off, but tea was the winner in the lab.
0:50:01 > 0:50:05So, in conclusion, in the lab and on the streets,
0:50:05 > 0:50:07tea is the dunking champion.
0:50:07 > 0:50:09- Absolutely.- That was a slam dunk.
0:50:17 > 0:50:19In London, two hours and 35 minutes
0:50:19 > 0:50:22after the flour arrived at the factory,
0:50:22 > 0:50:25my biscuits have made it to the packing hall.
0:50:25 > 0:50:27Fraser Jones has worked here for 20 years
0:50:27 > 0:50:31and he's going to fill me in on the final steps of their journey.
0:50:32 > 0:50:34- Fraser.- Gregg, you all right?
0:50:34 > 0:50:37I've watched these biscuits being made every single step of the way.
0:50:37 > 0:50:40- Yeah.- Once they come out into here, what happens now?
0:50:40 > 0:50:43Now we need to get them orientated ready for packing.
0:50:43 > 0:50:47We've got to do that as quickly and as gently as we can.
0:50:47 > 0:50:48We don't want to damage the product.
0:50:48 > 0:50:51So what's the first stage? What's this bit?
0:50:51 > 0:50:52We've got 18 lanes of biscuits
0:50:52 > 0:50:55so the biscuits come onto this air bed
0:50:55 > 0:50:59and these diverter arms split all the product into groups of three.
0:50:59 > 0:51:00Air bed?
0:51:00 > 0:51:03This table here has a big fan underneath
0:51:03 > 0:51:06that lifts the biscuits off of the surface
0:51:06 > 0:51:08so it cuts out all the friction,
0:51:08 > 0:51:11and we have a very gentle and smooth travel.
0:51:11 > 0:51:14It reminds me of an air hockey table.
0:51:14 > 0:51:16That's exactly the same philosophy.
0:51:16 > 0:51:19How many people munching a chocolate biscuit imagine
0:51:19 > 0:51:21that they may have floated into the wrapper?
0:51:21 > 0:51:24It's like a magic carpet ride for biscuits!
0:51:24 > 0:51:25What's the next stage?
0:51:25 > 0:51:28We split them into a further three channels, so these shakers...
0:51:29 > 0:51:33..divide the biscuits so we've now got six groups.
0:51:33 > 0:51:35So you can see, they're all interlocking
0:51:35 > 0:51:38and they're being presented perfectly to these slopes.
0:51:41 > 0:51:44Shaking dividers jostle the biscuits
0:51:44 > 0:51:46so they can make the perfect landing.
0:51:48 > 0:51:50One on top of the other.
0:51:52 > 0:51:55So they'll fall down this slope one by one and not two at the same time?
0:51:55 > 0:51:57- Correct.- Oh, my word!
0:51:57 > 0:51:58Who designs this stuff?
0:52:13 > 0:52:17I've been following these biscuits all the way along the line.
0:52:17 > 0:52:19Can I finally get to eat one?
0:52:19 > 0:52:22As it's you, Gregg, you can have a taste. Why not?
0:52:23 > 0:52:25I've waited a long time for this.
0:52:25 > 0:52:27Worth waiting for.
0:52:30 > 0:52:32At last! Well worth waiting for.
0:52:39 > 0:52:43As the digestives arrive at the end of this ingenious machine,
0:52:43 > 0:52:48they're divided into groups of 18 biscuits, ready for each packet.
0:52:50 > 0:52:52Then they're wrapped in a polypropylene sheet.
0:52:52 > 0:52:56Heated rollers seal the bottom and each end.
0:52:56 > 0:52:59- Where's it being cut?- Well, if you just look here, Gregg...
0:52:59 > 0:53:04you've got two shafts with heated knives, if you want,
0:53:04 > 0:53:06and that creates the seal
0:53:06 > 0:53:10and they're perfectly timed to cut the packet
0:53:10 > 0:53:13exactly in the middle of each stack of biscuits.
0:53:15 > 0:53:16And if that goes wrong,
0:53:16 > 0:53:18it starts cutting the packets of biscuits in half?
0:53:18 > 0:53:21Oh, yeah. Makes a right mess.
0:53:22 > 0:53:25- And it does happen, right? - Oh, yeah, occasionally.
0:53:28 > 0:53:31My batch of biscuits is now safely housed
0:53:31 > 0:53:34in more than 3,000 individual packets.
0:53:34 > 0:53:39Suckers lift and pack them into 277 boxes
0:53:39 > 0:53:41and then it's a quick seven-minute trip
0:53:41 > 0:53:44down a biscuit superhighway to dispatch.
0:53:54 > 0:53:58It's a land of robots, overseen by one man -
0:53:58 > 0:54:02Marcus Pymer, supply chain manager.
0:54:02 > 0:54:04Whoa!
0:54:04 > 0:54:06Now, this is a crazy room.
0:54:06 > 0:54:09Eight tangerine-coloured robots, right?
0:54:09 > 0:54:13- Yeah.- And they're all packing a different brand of biscuits?
0:54:13 > 0:54:15Yes, they are.
0:54:18 > 0:54:22As my digestives arrive, they're all mixed up with other boxes.
0:54:24 > 0:54:29This 115-year-old site is too small to send eight production lines
0:54:29 > 0:54:32straight into dispatch on their own conveyors.
0:54:33 > 0:54:36So they're merged onto just two lines
0:54:36 > 0:54:39and my boxes have to join the queue.
0:54:39 > 0:54:45- How does it work?- It's a bit like an airport baggage handling system.
0:54:45 > 0:54:47On the case, you have a QR code.
0:54:48 > 0:54:52I've got a camera that takes a picture of the code.
0:54:52 > 0:54:54Once it's taken the picture,
0:54:54 > 0:54:58the system knows which robot to put the case onto.
0:54:59 > 0:55:02My chocolate digestives are identified,
0:55:02 > 0:55:05separated out from the other types of biscuits,
0:55:05 > 0:55:09and directed towards the correct packing robot.
0:55:09 > 0:55:12Each one is named after a London station.
0:55:12 > 0:55:15Which station has got my chocolate biscuits?
0:55:15 > 0:55:19Your chocolate biscuits are being produced on St Pancras.
0:55:19 > 0:55:21No, I want that changed. I'm not happy with that.
0:55:22 > 0:55:25As a south London boy, that's disappointing!
0:55:30 > 0:55:33Each robot can pack 800 boxes an hour,
0:55:33 > 0:55:36stacking them in pre-programmed patterns
0:55:36 > 0:55:37and loading them onto pallets.
0:55:39 > 0:55:44From there, there's a signal sent to the two travel carts in the middle,
0:55:44 > 0:55:50so one will come down, pick up the full pallet and take it away.
0:55:50 > 0:55:52While it's taking the full pallet away,
0:55:52 > 0:55:55another cart will bring an empty and put it in its place.
0:55:58 > 0:56:02These are the pallets I've seen put together by the robots, yeah?
0:56:02 > 0:56:05- That's correct, Gregg, yes. - Right, and what stage is this, then?
0:56:05 > 0:56:08So this is just getting ready to load them onto the trailers
0:56:08 > 0:56:12- that are behind you, Gregg. - But where do you store them all?
0:56:12 > 0:56:16I don't. So basically, they come off that automated palletisation system,
0:56:16 > 0:56:19come on to here and then my forklift driver will load them
0:56:19 > 0:56:21onto the trailer behind you, and they go off.
0:56:21 > 0:56:24- So as soon as they're made... - Yeah.- ..they're boxed...
0:56:24 > 0:56:27- Yeah.- ..palleted and out?
0:56:27 > 0:56:28Yes.
0:56:28 > 0:56:30- No warehouse storage at all?- No.
0:56:30 > 0:56:33They only have enough space here
0:56:33 > 0:56:37to store two hours' worth of freshly baked biscuits.
0:56:42 > 0:56:44How many lorries go out of here?
0:56:44 > 0:56:47We average about 34 trailers every 24 hours.
0:56:47 > 0:56:49Nearly one and a half every hour?
0:56:49 > 0:56:52- Yes.- And what do you have nightmares about?
0:56:52 > 0:56:55- What worries you? - Um...conveyors going down.
0:56:55 > 0:56:57Trailers not turning up.
0:56:57 > 0:56:59- Weather.- Why the weather?
0:56:59 > 0:57:02Because we can't load your chocolate digestives if it's too hot,
0:57:02 > 0:57:04because it melts the chocolate.
0:57:04 > 0:57:07The one good thing about this, if you have any hold-up at all,
0:57:07 > 0:57:10- you can have a cup of tea and a biscuit.- Correct.
0:57:10 > 0:57:14From here, the chocolate digestives head to a distribution centre
0:57:14 > 0:57:16and off to the shops.
0:57:16 > 0:57:1984% are consumed in the UK.
0:57:19 > 0:57:22People in Sheffield and Glasgow are the biggest biscuit lovers,
0:57:22 > 0:57:25but Lancashire munches more chocolate digestives
0:57:25 > 0:57:27than anywhere else.
0:57:27 > 0:57:32I'm a Londoner and I had no idea in London was a factory
0:57:32 > 0:57:37churning out 13 million chocolate digestives every 24 hours.
0:57:37 > 0:57:39I certainly didn't expect to see them
0:57:39 > 0:57:41floating along on their own air bed.
0:57:41 > 0:57:44But what I learned that really surprised me
0:57:44 > 0:57:48was they put the chocolate on the bottom of the biscuit.
0:57:48 > 0:57:49Who knew?
0:57:49 > 0:57:51Raj, take it away, mate.
0:58:04 > 0:58:09It's taken a touch over four hours, but my biscuits are out and about...
0:58:10 > 0:58:14..heading towards the shelves of a shop near you.