Original subtitles

The first time I set eyes on these were in the school tuck shop,

and they've been a staple in our household ever since.

The only trouble is, these days, I've got three kids,

so I don't get a chance to enjoy them.

And I'm partial to a bit of snacking, too,

as, it seems, are most of the country.

In fact, we munch a whopping 100 million bags

of savoury snacks every week.

Before the glitz and glamour of TV, I used to work in a few factories.

And today, I'm back on the shop floor, cos I'm visiting

one of the UK's biggest snack factories...

..and I cannot wait to get stuck in.

Oh, ho, ho, ho!

They're all having a little jive as they go through!

I'm following the surprising processes...

Look at the size of these bad boys!

..that make millions of cheesy curls.

I don't know any food that's not improved by frying it.

But there's no such thing as a free lunch.

While I'm in here grafting, I bet you any money

Cherry Healey's out and about having a lovely time.

You bet I am! Because...

..I'll be finding out the secrets behind one of Britain's

favourite spicy snacks.

A Bombay mix waterfall!

And historian Ruth Goodman reveals the cheesy war story...

Oh, it feels very crispy.

...behind one of our favourite flavours.

This is the birth of the cheese snack.

These production lines knock out a staggering 500 million packs

of snacks every single year.

And I'm going to find out how they put that curl

in each and every one of them.

This is Inside The Factory.

This is the Walkers factory, in Lincoln,

and they've been making Quavers here since - get this - 1968.

That's a lot of Quavers.

All right, lads?

The factory operates 24 hours a day, seven days a week.

You all right?

All good?

And over the years, they've made various flavours...

This one's ready to go.

Full to the brim!

..including prawn cocktail, barbecue sauce,

and, of course, cheese.

Hands off it! All right, Paddy?

Get some work done!

And it's the cheese flavour I'll be following today,

as I learn how they make...

..these multipacks.

Living the dream.

Oh!

I love the smell of hot cheese in the morning.

I am definitely in the right place.

Let's get stuck in. Come on.

What factory director Layla Whiting doesn't know

about this savoury paradise...

This is amazing!

..isn't worth knowing.

Layla! How are you? Hello, Paddy. How are you?

It's a classic crisp everyone loves...

Whoa, whoa, whoa.

I need to stop you there. Yeah?

These are not crisps, Paddy.

These... Whoa!

To quote Eric Clapton, "Layla, you've got me on me knees."

These aren't a crisp?

These are not crisps.

A crisp is a potato that's been sliced and fried.

These are a snack.

What's the difference between a snack and a crisp?

Well, a snack is not sliced and fried.

These are made from potatoes, but, actually, the starch powder

from a potato is their main ingredient.

I have got to see it, Layla.

Let's get together. You go that way, I'll meet you...

I'll meet you the other side. Right, OK.

But before we can start making our "snacks",

we need the main ingredient...

..potato starch.

Luckily, Cherry is on the case.

Paddy, don't worry, I got this.

Intake is right here.

I'm at another Walkers factory 50 miles down the road,

in Leicester, and...

My potatoes have arrived.

They make more than 11 million packets of crisps here every day,

and they also produce the potato starch for Paddy's cheese curls.

Overseeing delivery is operations manager Katie Perry.

Katie Perry, lovely to meet you.

Hi, Cherry.

Chemical engineer Katie Perry.

Well, the crisp-making version.

Behind you, you've got a massive lorry of potatoes.

How many are in there?

There's 29 tons of potatoes on the lorry. OK.

We have 30 of those lorries arriving every day.

So, that's about 300,000 tons of potatoes every year

to make our crisps.

But you have a secret side hustle, don't you? Yes.

We're also using those potatoes to make our starch powder.

That's what I'm after.

When 29 tons of potatoes tumble off the lorry...

..the clock begins on our production.

First, the potato skins are removed by a series of abrasion peelers.

Lots going on here.

The peelings are used to generate 25% of the electricity

needed to run the factory.

And the skinless spuds are dropped onto eight spinning blades.

So, as the potatoes are sliced,

it breaks down some of the molecules in the potato,

and that starts to release the starch.

So, we're cracking them open... Yes. ..obviously, for crisps.

But what we're really getting is the starch. Yeah.

Oh, OK.

You can almost feel the starch off them.

It's almost soupy. They are, yeah.

Now it's all about extracting that starch for Paddy's snacks.

The slices plunge into a bubbling stream that not only

transports them, but begins to remove the starch.

Look at this! Wahey!

We're washing those slices, and spraying them with water

to take off that surface layer of starch.

OK, so, I can see the water is really milky, almost.

That cloudiness of the water is the starch particles

that are in the water.

So, at this point, the water contains about 2% starch.

So, potatoes carry within them a huge amount of starch?

Yeah. So, every potato contains, essentially, the energy

that it would need to grow a new potato plant,

and it does that in the form of glucose molecules,

which we're calling starch.

The sliced spuds are ferried to the fryer,

where they'll become crisps.

But I'm following the starch-saturated water.

So, these pipes above us here are taking that starchy water we've seen

in the factory, and bringing it over to our starch plant.

Here, the starch for Paddy's cheese curls

will be extracted from the water.

First, it's sieved to remove any remaining bits of potato,

before it passes through 11 hydro-cyclone machines,

which push the lighter water molecules away,

leaving the heavier starch behind in a more concentrated liquid.

Wow, look at that.

It's quite like cream.

It's so thick.

The liquid is now 80% starch -

but still not the right consistency for Paddy's snacks.

So, another machine continues the water removal process.

So, this is a rotary vacuum drum filter.

How does that work?

As this drum is spinning round, it's drawing water through

a mesh on the drum.

The starch particles accumulate on the outside of this drum,

until they become so thick that it's scraped off by the knife.

It looks a little bit like desiccated coconut.

But it's not quite like powder yet.

It looks like it might be a little bit moist.

Yeah, it's still not as dry enough as we need it.

It's got about 40% moisture in it, at the moment.

Extracting the last drop of moisture requires a final enormous machine.

Well, look at that!

The starch granules pass through a huge drying chamber,

where they're blasted with hot air at 150 degrees Celsius,

before emerging transformed.

Oh, look at that.

This starch powder is our finished product.

Oh, it's much drier.

So, you're happy with this?

So, this is ready to go in a tanker

and be sent off to the snacks factory.

But, first, do you want to build a snowman?

It takes 24 hours to make the starch powder.

And the factory produces 150 tons of it every week...

You're good to go!

..all of which goes to make the cheese curls at Paddy's factory.

It's a big moment.

It is. It's emotional.

Let it go, Cherry.

It's potato starch.

Every week, six 26-ton tankers make their way up the A46,

from Leicester to my factory in Lincoln...

..where the starch is pumped to the mixing area,

which is where I'm heading with factory director Layla.

Three points of contact on the stairs, Paddy.

Oh, I like that. Health and safety.

Yeah, very important. Very important.

Feel it getting warmer...

Oh, my word.

My...word, that is HOT.

Warm.

You know like when you get off the plane on holiday? Yes.

This is like the plane's landed on the sun.

So, it has to be a certain temperature in here

to allow for the starch to activate.

The teams are actually based in a control room,

and they'd only come here if there was a problem.

Oh...!

Oh, there's a problem already...

..under my arms are wringing!

The lads in the air-conditioned control room operate the entire

production line using just a few high-powered computers...

Woo!

..leaving me and Layla to soldier on in the 37 degree Celsius heat.

Layla.

I'm not bragging here - but I am hot.

LAYLA LAUGHS

Right, what is this? Is this the mixer?

Yeah. So, basically, here is where you have the starch -

which Cherry's provided - coming across,

and that makes up two thirds of the product.

Wow, that is the essence of the snack.

Why potato starch? Like, why not wheat?

So, potato starch is because we want a nice light,

fluffy texture at the end. Right.

If you use wheat, you'd have more of a heavy pasta.

Yeah.

I suppose when you get it out of the bag, they are quite light

and fluffy, aren't they?

And I can see with this stuff here, that is...

It's really fine, isn't it, and really light? Yeah, really fine.

Also pumped into the mixer are equally fine rice and soya flours

to enhance the texture.

Plus, some mild seasoning,

salt, pepper,

onion powder and yeast.

But no cheese flavour yet.

What's this little fella here?

So, this is one of the other ingredients - this is annatto.

Basically, what this does, is it gives it that

nice sunshine yellow colour.

It's more of a burnt orange kind of...

I call that David Dickinson.

Yeah!

Made from the seeds of the achiote tree in South America,

annatto is a colourant so concentrated that this

single 100ml cup...

..can colour 50,000 bags of snacks.

It's all then mixing here.

Imagine this is a huge mixing bowl. Yeah.

It's really, really important that you mix all of your dry ingredients

before you do anything else.

When do we start adding a bit of moisture?

We need to move on to where we're actually making the dough.

Let's go. Okey doke!

After three minutes tumbling in the mixer,

the control room boys release a whopping 130kg

of the dry ingredients into pipes.

At the same time, 70 litres of water is also sent

to a churning paddle mixer.

Oh, look at this!

That looks to me like a cheese being made.

It's like a curdle. Yeah.

And I think now you can see the colour starting to come through.

Yeah, definitely.

So, here we've got all the dry pre-mix

we just talked through coming in. Yeah.

And then we've also got water.

Almost a bit like a pasta when you're mixing it. Yes.

So, here, what this is pretty much doing is, it's mixing and kneading,

and removing the air from the dough. Yeah.

The water that's added here is about 88 degrees.

You can probably feel the heat from here. Oh, I...

From everywhere.

Honestly, I don't think the people at home watching this

will get how hot it is in here.

It is BAKING.

It is.

But it's really important it's that temperature, because what that

does now is, it starts to, like, set off the starch,

and the starch now starts to become more pliable and stretchy.

The heat causes the starch granules in the mix to absorb water

and swell, eventually bursting open,

thickening the dough and starting the cooking process.

So, what would happen if you used cold water?

Cold water, it wouldn't start the cooking process for the starch.

So, you wouldn't have that kind of nice stretchy material. Yeah.

Cos it'll impact that iconic curl that you get at the end.

We need the curl.

You need the curl. We need the curl. Exactly.

So, how long is that in there for?

About 20 minutes, from beginning to end.

So, should we go to the next stage?

Lead on. Lead on, Layla.

Once my dough is thoroughly mixed,

the cool lads in the control room send it along pipes

to the next stage of production...

..where it's undergone a bit of a transformation.

Here we go. What?

Do you know what, I'm getting, erm...

..lasagne-sheet vibes here.

That is so thin.

It's about 1mm thin, and it needs to be 1mm thin

so we get the right texture at the end.

What you've got behind here is something called

an Archimedes screw. Right.

It pushes the dough through this mould,

which we call a die head. Yeah.

Around 60 bar, which is about 30 times that of a car tyre.

So, pretty substantial pressure there.

And, basically, what that does is,

it extracts air from it, which is really important.

Can you remember, like, Play-Doh, where you had the Play-Doh toys?

I used to love that. The hairdresser's set, where you do...

and it all comes out like that at the top. Exactly.

Love that. Exactly the same kind of thing.

You're talking my language.

So, imagine that, but extremely tough Play-Doh

that we're pushing through.

And it creates these sheets.

Looking at this, you know, it is a million miles away

from what I recognise in them yellow bags.

I know. We've still got a long way to go.

We're still right at the very beginning of the process.

So, that is essentially a massive sheet of the curly snack?

Yeah.

But before this sheet of flattened dough can move to the next stage,

it has to go through a bit more torture.

What you've got here, these bars, these are really, really important.

So, what these will be doing is actually starting to add tension.

If you imagine an elastic band, where you pull it really tight,

which is really important later on for getting that iconic curl.

So, when we get to the fryer, it springs back to its original form.

So, that comes from that?

This is where we start that process, yes.

Do you know what, I thought you had someone on the production line

somewhere with a thumb... giving it one of them.

Just curling it around?

So, it all stems from that there? It all starts here.

I tell you what, you live and learn.

Come on!

This factory has precisely engineered every stage

of its production to deliver that iconic curly shape.

But Ruth is investigating a time when the bog-standard spud

was a much simpler snack.

The Industrial Revolution of the late 18th and early 19th century

demanded hard graft.

People worked 16 hours a day, six days a week.

Now, that builds up an appetite.

To help feed this ravenous workforce,

an army of enterprising food traders...

Eels for sale! Eels, eels, eels!

..lined the streets of Britain's booming towns and cities,

selling oysters, pies and chestnuts.

Oysters!

Hot peas! Get your hot pea soup.

Hot peas!

But in 1835, there was a new cry...

..for a food that quickly became the hottest ticket in town.

Roll up, roll up! Hot, mealy and floury.

Come get your baked potatoes.

Lauren Collier is curator at Blists Hill Victorian Town,

a living museum in Shropshire.

She's traced the rise of the potato in industrial Britain,

and how it became a profitable bestseller for Victorian

street food entrepreneurs.

Ooh, ho, ho!

Hot potatoes?

Yes, hot baked potatoes. Would you like one?

Oh, yeah.

Nice little hand warmer. Ooh!

THEY LAUGH

They are hot, aren't they?

People obviously ate a lot of street food.

Yeah, well, the thing that was so distinctive about

the baked potato is that it was relatively new. OK.

Fruit and other foods were very popular in the 18th

and early 19th century.

Baked potatoes only get very popular 1835 onwards, really.

So, how do we know that this was a popular street food?

Well, it's all thanks to a man called Henry Mayhew,

who was a journalist working in London in the Victorian era.

So, in the 1850s, he produced a series of articles, where he gives

really detailed insights into working people's lives,

in particular, the food that they were eating.

And he found out there were around 300 street sellers

selling baked potatoes in London,

selling about ten tons of baked potatoes every single day.

The population of London had almost tripled in 50 years...

Hot, hot, hot, hot!

..so the humble potato was promoted by the Ministry of Agriculture

as a way to feed hungry workers.

Hot, hot! Floury and hot!

The spud sellers capitalised on this growing demand,

moving their carts around to maximise profits.

And who exactly was buying these baked potatoes?

So, it was very much the working classes.

So, it would have only cost about 1.5% of a worker's daily wage.

So, really very, very cheap.

That is affordable, isn't it? Yeah, very affordable, yeah.

Even if you're working goodness knows how many hours a day

cobbling shoes, you're still going to be in a position

to have a hot potato at the end of the day.

One street seller, in Smithfield Market, reportedly sold

1,000 tatties a day.

And this burgeoning trade also drove a whole new

revenue stream for the bakeries.

This is a commercial baker's, then?

Yes. So, the potatoes would have been baked in ovens in the bakery

after the bread was done.

Mayhew tells us that they would have been baked for about an hour

and a half in much larger tins than this, about 300 at a time.

Cor!

Yeah, you could get 300 potatoes in there, couldn't you?

Definitely, yeah.

So, with their fee to bake each batch,

the bakers profited from tatties, too.

Oh, they look good. They smell good!

Yeah, definitely. Hang on. There we go.

Ooh...!

So, these are ready to go out on the street? Yes.

Fabulous!

Hot potatoes!

Hot, hot, hot!

The typical London trader sold 300 baked potatoes a day,

earning double the average daily wage

of his factory worker customers.

Roll up, roll up!

Potato, anyone?

And the perfect pitch was crucial.

So, we are outside the pub. Yes.

And 9pm was, apparently, around the best time

that they'd do their selling.

I mean, it makes such sense, doesn't it, when you think about that world?

So many people were in fuel poverty.

They did not have a fire at home. No.

They went to the pub to keep warm.

And then, you've got a hot meal. Yes.

Nutritious takeaways were a lifeline,

especially for the city's poorest workers,

crammed into factories and sweatshops by day

and slum houses at night.

To escape the cold, customers would often bring their hot baked potatoes

into the pub - to savour with butter and salt.

And after a hard day's work, what a nice way to end the evening.

Yes, definitely.

Flipping 'eck, Ruth. Get some cheese and beans on that!

Or at least a bit of tuna mayo.

Anyway, today, we're all about the cheese curls!

If we can find them in this labyrinth!

It's a bit like Willy Wonka's, where everything's connected

via pipes and taken to different parts of the factory. Yeah.

My dough has been on the move, too,

and we're meeting it at an 18-metre steamer.

Tell you what, it's a fair old length they've got to travel, Layla.

Inside, it's 90 degrees Celsius,

increasing the moisture level in the dough to 40%,

making it even more pliable and stretchy.

But now it needs to be cooled.

Oh, look at this!

So, Paddy, what we've got here is two huge fans. Yeah.

And what the fans are doing is, they're now cooling this down.

So, by cooling it down while it's still under tension on these belts,

it will lock that tension in, so when it hits a fryer

you get that lovely iconic curl.

With these fans here, I feel like Mariah Carey

doing one of them pop videos.

It's lovely, and it's very cool, as well.

There you go.

What we're also doing here is, we're starting to dry out the product.

Six metres of dough are cooled and dried every minute

as it passes through the rollers.

Next, we're going to move on to cutting it,

and we need it to be dry so it doesn't stick together.

So, are you cutting it into the exact size of the actual,

what you get out of the bag?

Let's go and have a look. Oh...!

You little teaser, Layla. Go on.

Watch your head. Watch me head.

After that much welcome blow-dry,

the dough is fed through more rollers..

..into a lethal-looking bit of kit.

Look at that!

So, what you've got going on here is, inside here, you've got

blades that actually cut these into strips of around 13mm wide. Right.

You've then got blades that then cut them into a single,

what we call a pellet, and those pellets are around 40mm long.

What amazes me with that, firstly, someone's designed that

to get the exact size of cutting them.

But, also, when I look at that, when I was a kid, did your mum ever

use to hang that thing on the door to stop flies coming in?

I can see the resemblance. Yeah!

Do you want to have a look at what they look like?

Yes, I do! Let's have a look.

That is what's in the bag?

Every single one of these is going to turn into one of those snaps.

How many is that cutting in a minute?

Each machine cuts around 7,900.

So, we've got four.

So, every minute we cut around 31,600 individual pellets.

And there's a little bit of stretch in them... Yeah, you can feel it.

So, currently these have about 40% moisture.

We need to reduce this down to 11% moisture. Right.

Once we do that, we'll get that lovely texture that we like.

Come on, then, let's make it better.

Let's dry out some snacks!

One day, one hour and 41 minutes into production,

my freshly-cooked pellets are on the move...

..to the drying area.

Oh, that's heaven. A little bit cooler.

That is so much cooler in here. It is.

Oh!

The pellets pass through a dryer, which works a bit like

a salad spinner, giving them a good shake and reducing

the moisture level to 25%.

Then they drop down a stainless steel plug hole,

and through even more pipes to the next stage.

I'm trying to take everything in as we're walking around.

But nothing quite prepares you for the scale of this place.

Look at the size of these bad boys.

So, these are humongous... I guess, like a tumble dryer.

That is a massive tumble dryer.

And I've got three kids.

I'd have a field day putting socks and underpants in that.

There you go. I'd have that done in no time. You would.

Inside, the moisture level is reduced yet again, this time to 11%.

See if I can feel 'em drying out in the...

Yeah.

Dry, my little friends!

And then, my tiny pellet pals...

Oh... Ho, ho, ho!

They're here, Paddy!

..make a show-stopping exit.

They're all having a little jive as they go through.

I know, they're having a little bit of a party.

This metal plate vibrates the pellets,

separating them in preparation for cooking.

Rock your body in time

But are they dry enough yet?

Coming out of here now, we should be at that 11% or so moisture point,

which is exactly what we want before it goes into the fryer.

Do you know what I thought before I come here?

The process is nothing how I imagined it. OK.

I thought, slices of potatoes, dead thin,

dried out somehow so they curl up,

then dropped into a deep-fat fryer.

I mean, it's literally nothing like that.

I was going to say, it's completely the opposite. Yeah.

When do we start seeing that curl?

That's the next stage.

That's what we're going to go see now. Come on.

It's what you've been waiting for. Thank you.

Rock your body in time

I love that! Hey!

I've always wanted to do this...

Ke-e-e-ep drying!

A little dancing thing there.

1.2 tons of bouncing pellets travel every hour

from the drying area... to the fryers.

So, this is where the magic happens, Paddy. Yes!

Love that.

10p for the toll, here we go.

Would you like me to put that down?

I would, since you are now a safety guru.

Look at that. So, we saw the pellets coming out before,

and now we're getting them ready to go into the fryer.

This piece of equipment here is the fryer itself.

So inside, a bit like your deep-fat fryer at home, you've got your oil.

I don't know any food that's not improved by frying it.

If it were up to me, I'd fry everything.

I don't care what they say.

So, in here, Paddy, it has a thing called a submerger belt.

And what that does is it takes these pellets down under the oil

and brings them back up again.

Inside the fryer, the pellets are plunged into sunflower oil

heated to 200 degrees Celsius.

The heat of the oil causes any remaining water inside

to turn to steam, puffing them up and leaving tiny air holes.

At the same time,

the tension created when the dough was stretched contracts...

..and curls up.

After 20 seconds in the oil...

Also Sprach Zarathustra by Richard Strauss

..1.8 million perfectly formed curls cascade out of the fryer every hour.

Ooh!

This is the shape that you recognise.

This is what you've been looking for the whole time.

This is what I've been searching for me whole life.

Now we've found it, the Holy Grail.

So, if you remember, upstairs we talked about stretching it out

like an elastic band, locking it in. Yeah.

And then, when it's gone in the fryer it's now snapped back.

We've activated that starch muscle memory.

And you get that snack that you recognise.

So, what would they be like if you taste them?

Why don't you have a go?

Let me get you some. Yes, I will.

Wow! You are spoiling me!

Potato starch snacks in a jug.

And my careers teacher said I'd never amount to anything.

Look at that. Dan the Cam, come in here.

Get on that, pal. Look at that.

Fresh.

Oh, they are toasty warm, them, aren't they? They are.

Does it taste...? I recognise the actual texture. Yeah.

But it reminds me more now of a prawn cracker.

So, as they come out of the fryer, they have a little too much oil on.

Yeah. So what we're now doing is vibrating that oil off. Yeah.

You want to keep some

because you'll need it for the next part of the process.

But obviously no-one wants an oily snack.

In a jug. In a jug! Yeah!

You just said I was spoiling you! I know!

The one thing it's missing for me... Yeah?

..is flavour.

So, let's move on to the next stage.

Is that where we add the magic...?

Cheese? That! I was prompting you there!

That's it.

I was like, "Layla, that's what we want!"

Layla, give me the cheese! Give me the cheese!

Come on! Go on, get going! Why? We need cheese.

While I'm on a cheese hunt...

HORN TOOTS

..Cherry has set her sat nav for another snack

that packs a mega punch of flavour.

I'm hot on the trail of the Indian snack, Bombay mix.

But I'm not in India. I'm in Leicester.

I'm at a company that makes 10 million bags of Bombay mix

every year.

This spicy blend of peanuts, split peas and crispy noodles

was originally a delicacy from the deserts of northern India,

known as namkeen.

The name Bombay mix was adopted in the early 1980s,

conjuring up the flavours of India for the British market.

Checking today's delivery of the first of five ingredients

is quality assurance director Nasir Jaffrey.

Hi, Nasir. Lovely to meet you. Hello!

What have we got here?

We've got some peanuts from Argentina. Ooh.

Why Argentinian?

So, these retain the best moisture.

What we're looking for is nice, juicy peanuts.

Do you get that undertone of sweetness? Mm-hm.

Why are they in their skins?

When we fry them, it gets really deep red.

We want that bright red colour.

Do they meet your seal of approval? Yes.

So where are these nuts headed? To frying.

My guide to a deep-fried peanut is operations manager Sunny Samra.

Whoa!

I think that is one of the biggest fryers I have ever seen.

How long is it? It's seven metres.

We fry it in rapeseed oil.

It takes three and a half minutes

for it to go through the frying chamber.

The peanuts emerge hot and crunchy

and enter a fairground ride of a machine.

Oh, Sunny! What's this? This is fun.

This is a tumbler.

It removes any extra skin.

It also cools down the nuts.

The factory uses 5,000 tons of peanuts a year,

but they only make up 7% of the mix.

My favourite bit forms 66% -

crispy noodles.

That is some mixing bowl.

Already in the bowl is water, rapeseed oil and chilli powder,

but the bulk of the noodle

comes from three different types of flour...

Oh, lovely, lovely, lovely.

..including potato starch, just like in Paddy's cheese curls.

It's going to mix for around about five and a half minutes.

Oh, look, we seem to have made a hot tub full of moulding clay.

It's really moist.

We want something soft and pliable, not something that's too stiff.

The malleable dough is the perfect consistency...

Off it goes!

..to be pushed through the tiny holes of the extruder

and into the hot rapeseed oil,

where it fries at 175 degrees Celsius

for three and a half minutes.

You call them noodles, and now I see why.

This is a thick noodle.

We've got a thin noodle

and we've got a gathia, which is a really thick noodle.

But I don't think that would fit in a Bombay mix bag.

It looks like a bird's nest. Yes.

So, at the moment they need cutting. Yeah.

So, right at the top there, that's where the cutter is.

Our cut noodles join the peanuts...

Well done!

..in a series of hoppers, ready for the final mix.

Oh, wow. Look at this!

Also fried and ready to revel are puffed rice, split peas

and green lentils.

Now to put the mix into Bombay mix.

Go! Go!

Woohoo!

What is this amazing machine doing?

Each one of these components is being fed through

in perfect portion to the tumbler at the end there.

Why do we love Bombay mix so much?

The British public's love affair with the Bombay mix

started in the Victorian period, and it goes back to colonial times,

where it was the perfect accompaniment with afternoon tea.

That's quite a spicy tea time snack.

Because they're adding a spice mix that includes chilli, garlic,

oregano, coriander and cumin.

Here it is!

A Bombay mix waterfall!

Wow, it's so colourful and beautiful.

It's punchy and spicy.

It's got quite a kick.

It does, it does.

All we need now is a party.

Yeah, we're going to have to invite a lot of people, I think.

If there's a party, I'm free, Cherry.

Back at the factory,

and I'm one day, three hours and 11 minutes into production.

My curls have been cut, dried and fried.

But there's still something missing.

That all-important cheese flavour.

Oh, yes! You can already smell it, right?

So, Paddy, you said you wanted cheese... Yes.

This here is our top-secret seasoning... Ooh!

..which actually contains a number of different things... Yeah.

..but, most importantly, it has real cheese powder.

Not that secret, if I'm being honest, Layla.

I mean, that is... Literally says that on the front of the packet.

We can't tell you what's in that, but it's cheese.

But it's cheese! Right, OK.

This highly concentrated recipe also contains garlic and whey powder,

but that's all I can tell you.

Can I taste a little bit of that?

Let me get you some. Right.

Ho, that's good!

Cheesy? Oh, I enjoyed that.

Did you actually? I did!

It was that powerful, it took me aback

and I went with it.

I bought it, and now I'm in cheese nirvana.

I can't believe you've got in for seconds.

Wow!

That's impressive. That is a treat.

This box actually can flavour half a million single snacks.

So that means that one I've just had probably about 150 bags' worth

of flavour on me finger.

On your finger. Wow! Look at that.

OK, Paddy, so we need to get this seasoning onto those snacks.

Right. So, Adam... How are you, Adam? You all right, pal?

He's the expert. You can do the heavy lifting.

Right, here we go. Where's this going, Adam?

Straight onto here for me, please. Right, OK.

That on there.

Let the flavour see the...

If only I could think of some of that rhymed with flavour.

I can't think of anything off the top of my head.

Right, here we go.

A 25kg box of powder is tipped into the hopper every 20 minutes.

Close that up.

The curls are weighed as they travel along a conveyor,

and an exact amount of flavour is dispensed.

Then, in a two-metre wide steel drum...

..the curls are fed in at the base,

and a waterfall of cheesy flavour is released from an arm at the top,

coating the tumbling curls below.

Aah, yes!

Can do you see flavour kind of trickling through. Yeah!

I can see the little fine dusting coming out of the arm.

Each curl stays in the mega drum for 12 seconds,

pirouetting along the ridges five times

so they're fully coated before they slip gently down the exit slope.

So, one of the other really important things is,

remember we shook off any excess oil? Yeah.

You need a little bit on

because that's actually what the seasoning sticks to.

If it didn't have any on,

the seasoning wouldn't stick to the snack.

So these are now, looks- and taste-wise,

exactly what we all know.

Exactly as you know.

Can I have a go?

You can. I think there should be a jug behind you, Paddy.

I was going to say, it won't be the same if it's not out of a jug.

There you are. OK.

Oh, look at this.

Fresh!

Go for it.

Wow.

That's what it's all about.

Do you know - who'd have thought potato starch can taste good?

That is unbelievable.

And again, you can see those lovely curls

which we've put in earlier with all of that manufacturing upstairs.

Yeah. And I've got to say, for the people at home, having them warm,

straight off the production line, is next level.

I'm still going.

This site has been home to these iconic curls since 1968,

but where did the idea of putting cheese flavour on a snack come from?

Ruth is on the trail.

When it comes to snacks like these,

cheese is the UK's favourite flavour.

It's something we've all grown up with,

but its origins are entirely American.

I'm at the restored site of a former American Air Force base

in Suffolk to hear a cheesy war story.

Hello, Giles.

Ruth! Hello!

I'd shake your hand, but you're full of boxes.

I know, give me a hand with these.

Come on. Oh, you've taken them all! I've got them. I've got them.

Fantastic. I've got them!

Scientist Giles Yeo has been researching the experimental

military origin of processed food,

and how cheese flavoured snacks

started with ration packs like these.

So, when the United States entered the war in 1941,

they had to move bulky ration packs to the front line.

One of the key items of ration packs nutritionally for soldiers

was cheese. Mm.

The problem with cheese is that it's got quite a bit of water in it,

so a cheese like this would have 35% water, adding to the weight.

And on top of that, if it's going to the tropics,

if it's going to the top of a mountain somewhere, you know,

there's hot, there's cold temperatures,

the cheese would then go off.

Over 7 million American troops deployed in countries

around the globe needed a super cheese.

Ooh, intriguing.

So the big idea to feed all the troops was dehydration.

OK. You remove the water, you remove weight.

Now, this was led by a US military research lab in Chicago.

There they assembled the greatest minds in food science.

Dehydrated food is easy to keep.

The Quartermaster Corps Laboratory

has established this in exhaustive tests.

It proved relatively easy to dehydrate vegetables

by removing their moisture using heat.

But cheese was a stickier challenge.

Now the problem is, when you heated cheese, this is what happens.

You end up with all this fat - disgusting, globby stuff

which made it very, very difficult to then dehydrate -

from there you just end up with a big oily mess.

In 1943, this chap named George P Sanders cracked it.

And this is a patent he filed for the free use of the people

in the territory of the United States.

And given that I'm American,

I am not actually breaking any patent laws...

RUTH LAUGHS I can show you how to do it.

Let's dehydrate some cheese.

Sanders discovered that a slower dehydration process

worked better for cheese, and it required two steps.

The first was to grate natural, full-fat cheese

under an electric fan,

and to leave it spread evenly at room temperature for an hour.

Right. And can you see the outside is dried slowly?

It then protects the fat on the inside.

Right. We can now heat it without all the fat spilling out.

So the next stage, we're going to stick it onto this dehydrator.

The cheese was sprinkled onto vented trays

and stacked for two hours above a dehydrator

set to a warm 63 degrees Celsius.

The moisture content was reduced to just 3%,

so this slower, two-stage process meant no more gloopy fat.

Aha! So, done!

Oh, it feels completely different.

Don't you think? Yeah.

It's very crispy and it snaps.

It does.

On top of that, because so much liquid has been removed

and bacteria need water to really grow,

this has now become pretty bulletproof.

The long-life dehydrated cheese was then compressed

to half the size of the original,

which made it easy to transport to troops on the front line -

a coup for the military propagandists.

So here is an advert for this dehydrated cheese.

I mean, look at it. First of all, look at the visuals.

I mean, it's slightly... LAUGHTER

So, we have a rather... A bare-chested chap.

..bare-chested, helmeted chap

feeding what looks like cheese on a stick

to a gentleman in a complete winter outfit.

"For jungle or ski troops."

"When the guns are hot and time is short,

"the cheese ration can be eaten as is."

Actually, this cheese ended up as a mountain ration.

For soldiers like these, fighting in the Italian Alps,

the mountain ration provided 4,800 valuable calories every day,

and the dehydrated cheese was a vital source of protein.

So, this here is the daily ration of cheese.

It's quite a weird experience because it does taste of cheese.

It's just the texture is completely different.

Really flavourful, actually.

I mean, everything else I'm seeing here looks supremely bland.

GILES LAUGHS It's just stodge.

Exactly. So if you needed a bit of umami, a bit of flavour,

then you may as well be sprinkling cheese.

But imagine if you're back at base,

you can sprinkle it over macaroni... Yeah. ..and over potato chips.

CHEERING

The war ended in 1945, but it wasn't the end for dehydrated cheese.

It became a huge commercial success in post-war America.

In 1948, Cheetos were launched,

which are extruded corn flavoured with cheese powder.

So it's changed from being a product that's about delivering protein

and fats to soldiers, to something that's just for flavouring. Exactly.

This is the birth of the cheese snack.

HORN HONKS

The idea of using cheese powder to flavour snacks

finally crossed the Atlantic

with Tayto's cheese and onion flavoured crisps in 1954,

in Ireland, and then Golden Wonder in Scotland.

And when Quavers were invented in 1968, cheese was the obvious choice.

Who knew my favourite flavour

is thanks to American wartime ingenuity?

Cheers, Ruth!

Back at the factory,

my snacks have been rocked and rolled in cheesy flavouring...

Dead end.

..and I'm heading to the bagging area.

'Ey up, pal, are you all right? I'm all right, Paddy.

How are you? Are you Eddie? I'm Eddie.

Layla's sent me up.

She's told me you're the man with the bags.

I know about bags. Right, OK, then.

So, what's going on here, Eddie?

Paddy, we are now starting to weigh the snacks

so that we can put them into the individual packets.

So the snacks fall onto the top,

and then they're fed into a little weigh scale.

So are these all essentially little scales?

They are, there's 14 individual scales on each machine.

So how does that do it?

Is it just each one, measure 16g and drop them down?

No, that's far too slow for our process.

The feeder drops the curls into the 14 scales, or buckets,

of the multihead weigher.

The computer detects the weight of each individual bucket...

..and then works out which three or four combined

will add up to the required 16g for every single bag.

So that is quicker than just literally putting them on a scale

and weighing 16g and putting it straight in a bag?

It would take time to do that, Paddy,

because you'd have to individually take some bits out.

If it's not got enough you'd have to put it in

and that's far too slow.

So we need to get production out the door.

Oh, right. OK.

So when they drop down there, where does it go to then?

Well, we'll have to go downstairs and have a look, I think.

Let's do it, Eddie. Lead on, pal. Lead on.

Clever little buckets, them.

So that's directly below where we've just been. It is, yeah.

This is the bag maker.

So, from up there they'll drop into the former.

That's just one long tube.

What are the actual bags made of?

An ultra-thin aluminium inside

covered by a plastic coating on the outside.

Aluminium? Aluminium. Wow, OK.

So, that helps the sealing process,

so we're not letting air into the packets,

which will make the product become stale.

The bags are sealed tight by jaws using a combo of heat and pressure.

All at 150 bags a minute.

Just 15 minutes after exciting the fryer,

the bagged-up curls travel to the penultimate stage of production -

the packing area.

That's where I'm going to go, Eddie. OK, Paddy. Nice to meet you.

Lovely speaking to you, pal. And you. You carry on here, mate.

Oh. I think we might have gone into the future here.

Check this out! Look at that!

Three robots run this bit of the line,

handling over 134,000 bags of snacks every hour.

Layla. Hello!

Look at this. I know! How cool is this? This is proper!

So, are they using suction? They are, Paddy.

So what they're doing is they're taking those single packs. Yeah.

They're then creating a six pack.

They're creating a six pack. They are creating a...

Let me lie on there...

..because I've been trying to create one of them for the last ten years.

Not worked, mainly due to them. You could give it a go.

They're using air suction, because we don't want to damage

any of those lovely snacks we've worked so hard to make.

I could stand here all day just looking at that.

As well as picking the bags up,

the robots use a red laser sensor to detect

if the packs are the right way round.

If they're not facing the right way, these heads then need to spin

to get them right in the right location

and that's really important,

otherwise you can have issues further down the stream.

You're talking to me.

I can't stop looking at them, honestly.

It's throwing me! I'm like, how are they doing it?

So, we're in there, it's put them into the sixes.

Then we go over here... Yeah.

..and that's when they get in the actual packaging.

Now we need to put it to bed.

Wrap it up.

Six 16g packets are wrapped in a layer of plastic

and sealed at the back and on both ends.

These clever robots sort 60 multipacks a minute.

And then place 30 of them snugly inside eight cardboard boxes,

again, every minute.

The boxes travel up a helter-skelter conveyor...

..before being stacked Jenga-style onto a pallet in towers of 20...

..and wrapped before hurtling across the factory to the dispatch area.

So it's been just over two and a half hours

since we got that starch...

Anything good on?

Never mind. LAUGHTER

Yeah? It's been just over two and a half hours

since we got that starch from Leicester.

We've got one more pallet to go on.

I reckon it should be you.

This takes me back to the days I worked in a warehouse.

Let's have a look.

The mighty pump truck. The mighty pump truck.

Oh, I'll do a drop and spin!

So, Paddy, on average, we have about 25 to 40 trucks

that go out every single day from here.

Every single day. Every single day.

There's 26 pallets on a trailer.

That's a total of 93,600 packets per lorry.

And with up to 30 loads every day, that tots up to - calculator out -

2,880,000 bags of cheese curls leaving the factory every day.

Look at that. Straight in. Oh, yeah.

There we go.

Well done. Thank you.

There we go. Good luck. Safe, on its way.

Do the honours, please. OK. Thank you.

Happy snacks. There they go.

Love that. Love that. Right...

Shall me and you have a cup of tea? Let's go. Through here.

Come on.

Just one day, three hours and 41 minutes

since the start of production,

my cheese curls are leaving the factory in Lincoln.

They make a pit stop at a distribution centre in Leicester

before heading to shops all over the UK,

with London munching the most.

Cheers, everyone. Thank you.

Well, I grew up eating snacks like these

and I always thought they were made out of potatoes.

Well, they are, kind of.

But I had no idea how complex the process would be.

So, that is essentially a massive sheet of the curly snack.

With these fans here I feel like Mariah Carey.

It's lovely and it's very cool, as well.

Oh, I enjoyed that. Did you actually?

I did!

And now I'm in cheese nirvana.

But the best thing I've learned today

is how they create...

..that gorgeous curl.

Who'd have thought? I wonder if it'll work on me hair?