All language subtitles for Inside.the.Factory.S02E02.Crisps.1080p.PMTP.WEB-DL.AAC2.0.H.264-BurCyg_track3_[eng]

♪ MTV ♪

[upbeat pop-rock music]

We are a nation of snackers.

Over the next 24 hours,

we will get through
1/2 a billion crisps.

- That takes
over 17 million potatoes a day

grown and harvested on UK farms
like this one in Hampshire.

Tonight, we'll reveal

just what it takes
to produce crisps

on such a mind-boggling scale.

As we give you a rare look

inside the largest
crisp factory on Earth.

I'm Gregg Wallace.

Bring her in!

And tonight I'll join the race
to keep up with demand

for our favorite snack.

That's a packet of crisps?

[laughs]

How does it do it that fast?

I'll meet the supertasters
testing every new flavor.

There is a sourness.

What, like curd?

It's a bit like baby sick.

- And reveal the tricks
this factory uses

to keep your crisps fresh.

In every bag of crisps
is a bag of nitrogen?

I'm Cherry Healey.

That smells really good.

And I'll discover the secrets
of the perfect crisp potato.

Why are they so dark?

- Because they have
a lot of sugar

which has caramelized.

- And the surprising ways
your brain can be tricked

into tasting something
that's not there.

It's really tricky.

- I thought I knew
a lot about crisps.

- Historian
Ruth Goodman uncovers

who really invented the crisp.

- We are gonna have
to rethink crisp history.

- I love this! I wanna ride
down this in a kayak!

We spend more on crisps than
anywhere else in Europe.

- Every day over
five million packets of crisps

fly out of this one factory.

It's an incredible feat
of logistics and engineering.

- You'll never look
at a humble packet of crisps

in the same way again.

- Welcome
to "Inside The Factory."

[upbeat music continues]

[word thudding]

[majestic rock music]

- This is Walker's in
Leicester,

the biggest crisp factory
in the world.

The crisp has gone
through something

of a gourmet revolution
over the last few years

and you can now get
all sorts of posh flavors

from langoustine and lemon

to white Stilton
and cranberry relish.

But tonight, we are following
the nation's biggest seller,

cheese and onion.

Which is a bit
of a disappointment to me

because I'm very much
a prawn cocktail man.

More than 40% of the crisps
eaten in Britain

come out of this one factory.

It runs around the clock,
seven days a week.

But whether they are
making ready salted

or something a bit more exotic,

the 24-hour production process
begins on the farm

with the right spud.

Almost all crisps
produced in the UK

are made with British potatoes.

The most popular varieties
are Markies,

Lady Rosetta, and Hermes.

[upbeat music]

The process of making
our crisps starts here

on the Hampshire potato farm
of Gavin Janaway

whose family have been growing
crisp spuds since the 1970s.

These will be going
to the crisp factory

later on today.

- Have they just been dug
or have they been in store?

- No, these have been
in store now

for about six months.

- We keep them
at the right temperature,

the right humidity
with fresh air going in there

because a potato is a living,
breathing thing.

You know, we've gotta try

and keep it happy
and keep it warm

so it produces a good crisp.

- How do you know when they're
growing in the ground

that they are gonna be
perfect for the crisp?

You can't tell.

- Well, to try
and help us tell, Gregg,

we've got our own little
frying facility on-site here,

our little potato lab.

And we take samples
from the field

throughout the growing season

and throughout
the storage season

and we take them through there
and we test them

and we actually
fry them ourselves.

So, I do my own little
"MasterChef,"

a little cooking myself, a
little bit of salt and pepper,

just the right seasoning.

We test them to make sure
they're right for the factory.

If they're not ready
when we fry them at the field,

we just give them
another couple of weeks

and a bit of sunshine
and everything

will help them mature.

[bouncy upbeat music]

- At any one time,
Gavin could be storing as many

as 160 million potatoes
on his farm.

When they get the order
through from the factory,

the potatoes are fed into
one end of a production line

which can sort, wash,
and load 27 tons of spuds

onto a truck in less than
45 minutes.

[potatoes clattering]

Here we go. A nice big crate
of British spuds.

How long before that lovely
spud

becomes a cheese
and onion crisp?

- That could be a cheese
and onion crisp

within six hours.

[upbeat indie-rock music]

- This is where our crisp
production line starts.

So, we're now just looking
for anything that's green

or has got damage on it
or maybe a little shoot on it,

anything that may
affect the quality.

- So, take the sprouts off.
- Something like this.

This is damage that's been done
through harvesting,

so that's mechanical damage,
that comes out.

- There's another one.
- That comes out.

Yeah, you won't beat him,
he's too quick.

He's the fastest one here.
Nobody beats Gregosh.

It doesn't surprise me

the best one here
is called Greg.

[Gavin laughs]

How often are you set up
like this?

- This is set up all year
round.

So we load any day
of the week all year round.

- Hey, a green one!
I got that before Gregosh.

How many potatoes
on a lorry load?

There's 27 tons.

So I think that works out

roughly 200,000
of packets of crisp

in one lorry load.

How many lorries go out?

- A busy day would
be 10 lorries.

So that means on a busy day

you send out two million
bags of crisps.

Yeah.

[potatoes clattering]

[forklift beeping]

[upbeat indie-rock music]

Have to admit,

I find potato shopping
a little bit daunting.

There are so many
different varieties

and I never know
which one to buy.

In fact, there are more than
230 varieties

of potato grown in the UK.

About half of those will end up
in your produce aisle

but the other varieties

are used to make everything
from frozen waffles to vodka.

But which variety makes
the perfect crisps?

To find out,
I'm heading to potato HQ,

the National Agronomy Center
in Cambridge,

where James Fowler
is a spud expert.

- Ready to go in?
- It's ready to go.

Here we go.

- We're going to have
a crisp fry up

but with three very different
varieties of potato.

I've brought some Maris Peers,

a waxy new potato
great for salads,

some King Edwards,

a more floury potato
perfect for mashing,

and James has got this one.

You won't have seen this one,

Cherry, it's a specialist
crisping variety

we're investigating
at the moment.

We think it's gonna
make good crisps.

- It's brand-new?
- Yeah.

It's a revolutionary potato.

The first obvious difference
is the shape.

Crisping varieties should
be predominantly round.

Not long like this Maris Peer.

If they're too small,
the crisps are too small

and the bags look half empty

and also there's a lot
more peeling waste

when you process them.

[upbeat pop music]

- But the differences
are more than skin deep.

When it comes to making crisps,

there are three key parts
of a potato,

water, which makes up about
80% of the average spud,

starch, and tiny amounts
of natural sugar.

Using a hydrometer, you can
tell how much water there is.

My two potatoes
are about 80% water

but a good crisp
potato has only 75%.

The less water, the better

because you need to get
rid of almost all of it

to make a crisp.

Now the fun bit.

Now we fry all three potatoes
in exactly the same way.

The water is boiling off.

- And that's what's causing
all this steam?

That's right.

- If there's more water
in a potato

when it goes to the factory,
you get more steam.

And fewer crisps.

- That's not what you want
if you're making crisps.

But when it comes
to making light, golden crisps

on an industrial scale,
the biggest enemy is sugar.

Wow.

Why are they so dark?

- Because they have
a lot of sugar

which has caramelized
and produced the dark color.

- The King Edwards
have less sugar

and so are noticeably lighter.

Finally, we fry the
specialist crisp potatoes

at the same temperature
as the other two.

Not only do they cook
much faster,

they look completely different.

- They look better.
- Wow!

So those are much more
familiar.

- Well, less sugar.
- Less sugar.

- Less sugar,
there's no color development.

- The subtle
differences of potatoes

might not matter much

if you're just having
a fry up at home

but for the nation's
biggest crisp makers

making tens of millions
of them every day,

the science of spuds
is everything.

[munching]
Mmm!

[upbeat electro-rock music]

Yeah!

Come on, bring her in!

How many potatoes have we got
on there, do you know?

- There's about 200,000
potatoes on average.

- And how many trucks
like that come in every day?

- We get about 25
every single day,

24 hours a day.

So, that's about five million
potatoes every day.

How many potatoes

in one standard
packet of crisps?

- Well, we're using about
five million potatoes every day

and we're making about
five million packets every day.

That's a packet of crisps?

Dead right.

- I love this.
I absolutely love it.

Potatoes are much more delicate
than they might seem

and can easily bruise.

So, the best way to get
200,000 spuds off a lorry?

Float them off.

Fire her up! Let's go!

[water rushing]

Yay!

That's a fair amount
of water there, old son.

They basically flood
the compartment of the truck

and the potatoes just come out
with the water.

Exactly right.

But that now
is a very wet potato.

I mean, that is gonna start
to deteriorate.

You can't keep potatoes
in water.

- No, so, time is of the
essence but in 35 minutes,

it's gonna be
in a packet of crisps.

- Just over half an hour
and you turn that into crisps.

I can't make chips in that
time.

[water splashing]

[upbeat pop-rock music]

[potatoes rattling]

When you're dealing with
five million potatoes a day,

you need an efficient
way of peeling them.

And here, in the world's
biggest crisp factory,

they have to peel more
than 2,000 every minute.

To do that, you need some
hardcore potato peelers.

[potatoes whooshing]

- We're using a thing called
abrasion peeling here.

Something that your grandma

actually might've had
in her kitchen.

We're spinning the potatoes
round against a rough surface,

a little bit like sandpaper,

and just removing
a small amount of that peel

to leave a clean potato
ready for the next process.

- That's quite
an aggressive rumble.

You cannot only see it, you can
feel it under your feet.

How do you know you've
peeled them all properly?

Because even if I do
half a bag of potatoes,

sometimes I might miss a bit.

- We've got a whole series
of digital cameras here

and they are looking
at every single potato.

- It photographs
every single one?

Every single one.

To the side here, you can see
what looks a little bit like

a piano keyboard,
a series of fingers.

If we get a bad
potato coming through,

you'll hear a gust of air

[machine thuds]

and that will kick
that potato out,

that will be rejected.

That's a bit nuts, mate.

[machine thuds]

[laughs]
How does it do it that fast?

[machine thuds]

My potato is about to be
sliced and fried

and turned into a crisp.

A process that will be repeated
five million times today.

But who first did it?
Who invented the crisp?

That's a question Ruth
Goodman's trying to answer.

And it's not as simple
as it sounds.

- [gentle upbeat music]
- [birds chirping]

If you speak to Americans,

they will tell you that they
invented the crisp in 1853.

And that it's down to a man
called George Crum,

a chef who was working
in a country club

in New York state.

The story goes
that the chef Crum

had a particularly
difficult customer,

a wealthy industrialist,

who kept sending his chips back
saying they weren't thin enough.

George got so fed up in the end

that he decided
to make the chips

so thin that they
would be inedible

and then he covered
them in salt.

Much to his surprise,
the customer loved them.

So much so, that he put them
on the menu.

But for me, there's something
fishy about this story.

We've been cooking
potatoes for 200 years

before the Americans claimed
to have invented the crisp.

Surely we'd come up with
a similar recipe before then.

[gentle rock music]

To get to the bottom
of this mystery

and find out once and for all
who invented the crisp,

I'm meeting food historian
Regina Sexton

to plot the history
of the humble crisp.

- The potato is in England
by the 1580s, the 1590s,

is looked upon
as an exotic thing.

So, it's something desirable,

a plant for people
to have in their gardens.

Gradually, potatoes

moved from being
just a specimen plant

to become something
that we started to eat

and by the 18th century,

they had become
the staple of the Irish poor.

Soon they were eating
an astonishing

12 to 14 pounds
per person per day.

I can hardly even lift that.

That is a huge amount of
potato.

It is.

But that's it.

That's the only thing
you eat all day?

Yeah.

- As Britain's population
exploded in the 19th century,

the potato became
a culinary mainstay.

One of the most popular
Victorian cookery books

was William Kitchener's
"The Cook's Oracle,"

first published in 1817.

- This book, in fact,
was a bestseller in its day.

- Really?
- I love this.

"The vegetable kingdom affords
no food more wholesome,

"more easily procured,
easily prepared

"or less expensive
than the potato."

- It's packed
with potato recipes

including one that's
quite familiar.

"Potatoes fried in slices
or shavings."

- Now, that's
a really interesting recipe

if you read through it.

"Fry them in lard or dripping

"and keep moving them
until they are crisp."

Crisp.

- What date did you say
this was?

- 1817.
- 1817.

So, that's quite
a bit before 1853

when the Americans say

they invented the crisp,
isn't it?

Yes, it is.

So, if we cook this

and it really turns out
to be a crisp,

then we are gonna have
to rethink crisp history.

I think we might have to.

[upbeat folk-rock music]

The only way to find out

if this really is the very
first recipe for crisps,

36 years before it was claimed

that George Crumb invented
them in America,

is to try out the recipe
for ourselves.

So, "Peel large potatoes.

"Cut it into little slices
about 1/4 of an inch thick."

- Lard to go in there.
- Yeah.

- "Put it on a quick fire."
A fairly hot fire.

They look like
they're cooking nice.

They've gone pale,
they're rising to the top.

- Excellent.
- Bubbling like crazy.

- "Keep moving them
till they are crisp."

- Oh, that's puffing up
a little bit there.

Smells lovely.

- "Take them up and let them
drain in your sieve."

Okay. "A very little salt
sprinkled over them."

Yeah.

- They smell like crisps,
don't they?

- They do, yeah.
- [laughing]

More salt. [munching]

It looks like a crisp.
It smells like a crisp.

It tastes like a crisp.
That is a crisp.

So, would you say
that the invention of the crisp

is definitely before
the American story?

Certainly.

If you do this recipe,

you produce fried
slices of potatoes

that are certainly crisp.

- So it looks like us Brits
really did invent the crisp.

[upbeat pop music]

- Back at our factory
in Leicester,

our potatoes have been
cleaned and peeled

and are now heading
for the knife.

The first step is to make sure
they're all the right size.

So, what we've got here
are our potatoes

and they're getting presented

across the top
of this screw deck.

And as you can see,

the smaller ones
are falling through,

they don't need cutting,
they're already the right size.

But there's a few
that are coming through.

They're a little bit bigger

and they are heading
for the guillotine.

So, we're gonna cut
those potatoes in half.

- So the French peasant
small potatoes

are falling through the holes,

the aristocracy is going
across the top here

to meet Madame Guillotine.

Can you tell in a bag of crisps

whether you have got crisps
that come from a hole

or a cut potato?

- I'm gonna let you
into a secret,

which is if you look
at those crisps,

if it's got a straight edge,

it's been halved
on a machine like this.

- I'll have a look
when I get home.

Very good.

- So, now we've got
the right size,

are they gonna be sliced?

We're ready to slice.

How long have you got left?

You've got about
20 odd minutes left.

[upbeat pop-rock music]

Next, my spuds take
the conveyor belt

up to some of the fastest
potato slicers on Earth.

Inside these machines,
there is a drum

spinning at very high speed.

When the potatoes
are dropped into the drum,

the centrifugal force
flings them to the outside

where an average potato
is cut into 45 slices

in around 0.2 of a second.

Wow!

That's unbelievable!

It's all done by eight
hardened steel razor blades

which constantly need changing

and that job falls
to Sudhir Raval.

That's incredibly ingenious.

As that spins really fast,
the potatoes...

But they stay on the outside
of the drum.

That's right.

And as they turn round, they...
Wow!

There are 33 slicers
throughout this factory

and they get through almost
2,000 blades every day.

You never actually
touch the blade,

you use the magnet.

I wanna be the razor blade
salesman here.

[upbeat pop-rock music]

Can I check my slices?

- Yes, we can do.
- I've done a good job there.

The slices are
constantly checked

to make sure they're being cut

to precisely
the right thickness.

[upbeat rock music]

Then they're off.

Racing down a giant
river of potato.

[water rushing]

I love this. I wanna ride down
this in a kayak.

- Now, the water you
can see here is milky

and that's because
it contains starch.

The starch has come
out of the action

of cutting the slice.

Water taking the starch out.

Another spray of water
to wash more starch out,

another bath to get
the starch out,

and another spray.

And that is to stop them
being so starchy

that they stick together
as a clump.

Is that right?

Absolutely right.

- I can guarantee they're
the right thickness.

I've been up there changing
the blades and measuring them.

What you can see here,
they go through the hairdryer

and what we are looking for

is we talk about the slices
dancing a little bit.

So they're bouncing around

and that means there's just the
right amount of air pressure

to just dry that slice out
just enough.

- Now my slices
are ready to be fried.

The factory has seven
mammoth industrial fryers

running 24 hours a day.

They're filled with
a blend of rapeseed oil

and sunflower oil trucked
in from southern Europe.

All major crisp manufacturers
in the UK

now use sunflower oil instead
of traditional cooking oil

as it contains less
saturated fat.

What temperature?
Am I allowed to ask?

So, it's around 180 degrees C

but we'll move that
up a little bit

and down a little bit
according to the potato.

So, we'll make adjustments
to the temperature

and also to the time.

It's around three minutes

but we'll adjust it according
to the product.

- So, those potatoes,
that I watched come in,

you will adjust the temperature

to cook those differently
to the others?

Exactly right.

As they fry,

the water inside our
potato slices is boiled off

and replaced
with some of that oil.

An individual bag of crisps

has just over 1/2
a tablespoon of oil in it,

which means these fryers
are getting through

tens of thousands
of liters of oil a day

and need to be topped
up continuously.

That is the most crisps
I have ever seen in one place

and I've been to a few parties.

These haven't got a flavor
on yet, have they?

- Nothing.
- No. Nothing at all.

This is pure
unadulterated crisp.

- I've never had a pure
unadulterated crisp.

- Would you like to go fishing
for crisps?

I'm gonna test your knowledge.

What's special about that
crisp?

Oh! That's been cut.

Yes!

You've been paying attention.

Hot crisps.

You've never tasted better.

Lovely crunch.

Needs a little bit of salt,
mate.

I don't suppose you've
thought of that.

[upbeat indie-rock music]

Back in Leicester,

we're a little over four hours
into the process.

My crisps have just
come out of the fryer

and before they can be
seasoned,

they have to be inspected.

Every single one of them.

Tell me how you can look
at every single crisp.

- Inside here you can see
the bright light

and we have a digital camera

which is inspecting
every single crisp

- passing the crossing.
- How fast is that going?

- That machine is handling
450 crisps every second.

And then the machine
is making a decision to say,

"Yes, it's good,"
or, "No, I'm gonna reject it."

It's using a fine jet
of compressed air.

Hang on, hang on, hang on!

At 450 crisps a second,

the machine
is taking photographs

and then directing a jet of air

to knock them off
the production line?

Exactly right.

I can see the crisps dropping

but they look like
they're just falling.

They're actually
being knocked off

by a computer-directed jet
of air.

That's James Bond, that is.

And there's an evil genius
sitting somewhere

that devises all this?

Is he's stroking a white cat?

[Simon laughs]

So, this is all about color.

So, it's looking for a color

that you wouldn't
want in the bag.

As Cherry discovered earlier,

if a potato contains
too much sugar,

that sugar will caramelize
as it's fried

giving the crisps a brown
color.

But it's kind
of not fair, is it?

Because some farmers'
batch of potatoes

might have less reject crisps
than others

or am I getting,
like, too pernickety?

- Well, we would love
all our farmers

to produce great quality

so we recognize that.

So, for the best potatoes,
we pay a quality bonus.

- So every batch of potatoes
that come in, mine as well,

all right, everybody gets it,

the farmer knows
what he's gonna get.

But if they get less rejects,
they get a bit more?

- Exactly. Because we're making
a few more bags of crisps.

- I bet mine were perfect.
You can pay me in cash.

[Simon laughs]

[upbeat indie-rock music]

My potato slices have been
dried, fried, and scrutinized

and now they're finally
ready to be flavored.

They travel on a system
of vibrating conveyors,

which is the only way
to move crisps quickly

without breaking them,

and eventually arrive at one
of 23 giant seasoning drums.

Welcome to seasoning.

- That aroma
is instantly recognizable

to anyone who's ever
opened a bag

of cheese and onion crisps.

That's quite incredible.

What's happening exactly?

- What you can see
before you is this drum

and what we're using
the drum to do

is to gently tumble those
crisps

so that we get a perfect
coating of the seasoning

on both sides of the crisp.

You can see behind,
we've got a powder.

So we're dropping it,
sprinkling it across the crisp.

- So, when I open
a packet of crisps,

what percentage
of it now is potato

and what percentage
is seasoning?

What's the ratio?

- Yeah, well, in the case
of cheese and onion,

we put about 6% of cheese

and onion seasoning
on our crisps.

- I love the fact...
Can you kneel a little bit?

'Cause I like having my crisps
served on a silver tray,

still warm.

That's a flavor and a texture

that I've actually
grown up with.

You know what I fancy
now though, don't you?

Is a pint of beer.

[Simon laughs]

The time between now

and getting them in a bag
must be crucial.

Absolutely.

So, from here to a bag
is only about three minutes.

It's a crisp superhighway,
isn't it?

[upbeat indie-rock music]

They get through more than
450 boxes of seasoning

every day in this place.

It's all made off-site
by large seasoning houses.

But what surprised me is that
almost every new crisp flavor

this factory comes up with
starts off as a real dish,

cooked by a real chef
here in the factory.

Ben Barlow is in charge
of the development kitchen.

He's invited me in to taste
some of the dishes

his team are cooking up

as they develop
new crisp flavors.

- A lot of the flavor
actually is the batter.

I'm helping him develop

a new cheesy beans
on toast flavor.

Make one that you wanna eat

and I'll make one that I think
the public will wanna eat.

- All right.
What are they, chef?

They are homemade ones.

I wanna put a little bit
of Parmigiano on it.

It can take over a year
to develop

and launch a new flavor.

It all starts with
Ben and his team

cooking up dozens,

sometimes hundreds,
of variations

and then trying to identify
the subtle flavor difference

in each one.

Here we go. So this is ours.

We start breaking it down,
and that's what we do here.

We break it down into each
of its taste components

and then try and recreate
that on a crisp.

Actually, start thinking
about cheesy beans on toast,

it's quite complex.

Just describe to me
the flavor journey.

So, what are you getting first?

What's starting
to come through second?

For me, first of all,

the unmistakable
smokiness of paprika.

Then, after that, straightaway
we're into the fruity richness,

almost sweetness, of the beans.

Yours did have
a cheese flavor, mine didn't.

Once Ben's decided

which version of cheesy beans
on toast is right,

he then needs to have
that flavor produced

on an industrial scale

by Europe's largest
seasoning houses.

But first, he has to describe
the specific taste

he wants them to create.

- I wanna say, "Right,
I wanna taste the beans first,

"I then want some toast
and butter coming through,

"and then I want it
to finish with cheese."

[gentle pensive music]

At the seasoning house,

a team of food scientists use
a complex combination

of mainly natural
and some processed ingredients

to match the flavor
Ben's described.

Once they've got it right,

it's produced in vast
quantities

in 2 1/2 ton mixers
and trucked back to the factory

where, in total,
they get through more than

10 tons of seasoning a day.

But before Ben's new flavors
get anywhere near the public,

they have to get past
a panel of supertasters.

- So, if we taste
sample E again.

- Cheese note there,
isn't there?

- Yeah.
- Feels like black pepper.

- There's no burn, is there?
- That's quite smoky.

- Every day, a group
of hand-picked

specialist crisp tasters
meet to sample new flavors

and check the existing
ones are up to scratch.

Hello, guys.

- Hi, there.
- Mind if I join you?

- Not at all.
- What are we doing?

- We are looking at developing
a new flavor today.

R&D want some feedback,
so let's get straight into it.

If we taste sample A first.

Getting quite
a strong tangy note.

- Cheese.
- Perhaps cheese.

That's definitely cheese,

but that's quite mild

and it hasn't got
the tang of a cheddar.

- Okay, so, what are
the key differences

between samples A and B?

- Heat.
- Heat and spices.

- You're right,
it's got a spice finish.

Stays on your tongue.

- There is a sourness,
isn't there?

- A dairy sourness
- A dairy sour.

What, like curd?

- It's a bit like baby sick.
That butyric acid sort of thing.

- Well, either you've
tasted baby sick

or you were a baby
a little while ago.

I mean, I don't know
how you're getting that.

[upbeat music]

Any new flavor,
even a new potato variety,

has got to get the okay
from this team

before it goes any further.

So, there are some
very influential

tongues in this room.

Is this your job?

This is my only job, yeah.

- And are you proud
when you go to a party

and people wanna
know what you do?

- I am very proud, yes.
- [all laughing]

- Is there any chance
your palates

can kind of, like, run out?

- Yeah, I think as
you get older--

Can change.

- Your taste buds change,
definitely.

- So, the guys are monitored
constantly to make sure

that they can still taste
at the highest possible level.

Thanks for your
years of service,

but I'm afraid your palate
is all washed out.

We've got you a watch.

[all laughing]

We were gonna have a party,
but what's the point?

You can't taste the food.

These professional tasters
are able to identify

the most subtle of flavors,

but, as Cherry is discovering,
our experience of food

depends on a lot more
than just taste.

- [birds cawing]
- [upbeat pop-rock music]

- Have you ever wondered
why fish and chips

taste so much better
by the seaside,

why a whisky always
tastes better by the fire,

or why wine you drink in France
just doesn't taste as good

when you get home?

Charles Spence is professor
of experimental psychology

at Oxford University

and his research has helped
uncover the answers.

I'm hoping you can tell me
why fish and chips

taste so much better
by the seaside.

Our brain, all the time,

is picking up information
from around us

and using it to infer
what we think we're tasting

and how much we think
we're enjoying it.

So, if we're eating those fish
and chips by the seaside,

then you would imagine

there's the smell
of the salty sea air,

maybe the sound of the
seagulls.

Making the leap
that the sea is just there,

that fish is fresher.

It's all really happening up
here in our head.

And as your brain combines
all the senses

and glues them together

in ways that the science
is just starting to reveal.

[upbeat electro-pop music]

- Professor Spence uses
innovative lab experiments

to investigate just how our
taste is influenced and confused

by our other senses.

Now we are going
to test them out

in the real world

to find out what happens
when we eat crisps.

Here, in the pubs of Brighton,

we've got no shortage
of unsuspecting subjects.

Would you do us a massive
favor and eat crisps?

Yeah.

- First, we're going
to take away

people's sense of smell

to see if they can still
identify the flavor

of a beef crisp.

Can you smell anything?

Can you give me a...
[sniffing]

- I can't open my nose.
- Nose at all. Perfect.

What flavor do you
think they are?

It's really tricky.

[Charles laughing]

Are they a bit oniony?

This is so weird.

[upbeat electro-pop music]

- What would you say
the flavor was?

Maybe bacon, I think.

I'd say chicken.

Cheesy, cheese and onion.

- It tastes just like
cardboard, no taste.

Take your nose clip off.

I know, it's beef and onion.

- Can you tell
the real flavor is?

It tastes beefy.

- Beef, roast beef.
- Yes!

So, did you notice
a significant change

after you could smell?

- Yeah, it was completely
different, yes.

- No one we asked could
determine the flavor,

proof that smell
is fundamental to taste.

- We think we're tasting
things,

we experience the taste
of the crisp in our mouth,

but, in fact, maybe as much
as 75% to 95%

of what we think we're tasting
is really coming from the nose.

Every time you swallow,

a little bit
of the volatile aromas

that we've made in our mouth

are kind of pushed out
of the back of the nose.

[sniffing]

And that is what we think
of as taste

but it's really smell.

[upbeat indie-rock music]

- The next surprising
experiment aims to show

that our enjoyment of crisps

can be somehow influenced
by what we hear.

- Gonna get you to put
some headphones on.

- Can we convince people
that identical crisps

have different crunchiness?

- Close your eyes
and put your hand out

and we'll give
you the first one.

- They need to rate
the crunchiness

on a scale of one to 100.

- 60, maybe.
- 60? 50?

- On the second identical
crisp,

Professor Spence
now uses a computer

to increase the volume

of the high-pitched sounds
in the crisps crunch

being fed into the headphones.

- I think crunchier.
- Crunchier.

How much crunchier?

Hmm, quite a bit.

So maybe a 90.

- That's crispier,
I think. About 90.

90?

- 90.
- 90.

Like, an 80 or 90.

- Ooh. Okay.
- So significantly crispier.

- Are you surprised to know
that both of those crisps

are from the same packet, both
exactly the same freshness?

- I thought I knew
a lot about crisps

but obviously not.

[laughs]

- Professor Spence's studies
show on average

subjects believe it's around
15% crunchier

when the sound is manipulated.

It did make a big difference.

- The noise crisps make
when you eat them

gives our brain information.

Subconsciously we associate
the crispier crisps

with being more appetizing.

Think we're tasting
the crunchiness

between our teeth
and in our mouth,

but in fact, all the time,

our brain is picking up
the sounds of crunch or crackle

and those sounds
are very informative

about what we're
actually tasting.

Every time we crunch
into something,

our ears hear those sounds,

and depending
on the frequency spectrum,

how loud the crunch,

we use that to infer how crisp,
how fresh the food is.

- From these experiments,
it's clear that smell

and sound are critical
to our taste.

So, next time you eat a crisp,

stop to think about
how many different senses

are influencing
your enjoyment of it.

Or not. You gave me a stale
one.

[upbeat music]

[upbeat folk-rock music]

- It's been less than
4 1/2 hours

since my potatoes were sitting
on the farm in Hampshire.

They've been peeled,
fried, seasoned,

and now they just
need to go in a bag,

which presents the next
challenge for this factory.

How do you fill a bag
with an exact weight

when no two crisps
are identical?

The answer lies in one of the
craziest rooms I've seen.

[upbeat whimsical music]

Julie Biddles
is responsible for filling

hundreds of thousands
of bags of crisps an hour.

This is quite
an extraordinary room.

Yeah. Very good, isn't it?

- I don't think anybody
ever would have seen

anything quite like it, ever.

How many of these things
are there in here?

There's 118.

118 of these individual...

And tell me, is each one
of these little buckets

with the numbers on, is each
one of these a bag of crisps?

No.

It's a weighing machine
and it will use

three to four combinations
to make one bag

but you might have
a little bit in each one

to make up the 25 grams.

- Inside this little bucket
now it's being weighed

and then a computer will
choose a combination

of four of these
to make up one bag.

- Whichever the best
combination is to make that weight.

- And the computer
will quickly add up

how many of those buckets
makes a 25-gram bag

and shoot them down.

- 30 milliseconds it takes
to calculate the weight

and then it will drop it.

- Every time we hear a click,
that's another bag of crisps.

That's a bag.

[upbeat whimsical music]

- And people must be eating
them

at the same pace
as you're making them.

So, every second,
a bag of crisps is being eaten.

[machinery whirring]

- 24 hours a day,
seven days a week.

- We are a serious nation
of crisp munchers, aren't we?

[upbeat indie-rock music]

The instant they are weighed,

the crisps drop through
the bottom of the machines

into waiting bags below

and it's all happening
hundreds of times a second.

[upbeat indie-rock music]

I wouldn't have believed
this was possible

if I hadn't seen it myself,
but less than 30 minutes

since my potatoes were sitting
on the back of a truck,

they're now crisps in a bag.

But before that bag is sealed,

there's one last
surprising thing to be added.

So, is that air you've
pumped into there then?

- What we've got inside
the bag there is nitrogen.

- That keeps it fresh.
- Really?

- There's two main
constituents of air.

One is oxygen, fantastic,
it keeps you alive,

but it's the enemy of food.

It would make our crisps
go stale.

The other thing,
which is the majority of air,

is a thing called nitrogen.

We put nitrogen in the bag

and that's the reason
you get that fresh taste

every time you open a packet.

- Every bag of crisps is a bag
of nitrogen, is that right?

- It's a bag of crisps
full of nitrogen.

- I'm taking for granted
that's safe, right?

- Perfectly safe.
It's all around us.

- So, oxygen deteriorates food,
right? I get that.

Got it.

But nitrogen doesn't,

it will kind of keep it
in suspended animation.

- Stable, yeah.
It preserves it for longer.

- What would happen if you
didn't flush nitrogen through?

What would happen, do you
think, if you just flushed air into it?

To try and answer this
question,

Simon's got two bags of crisps,
both three months old.

- Do you think I will know
the difference?

One is a standard bag that
was filled with nitrogen

and the other was
filled with normal air

to see if I can
spot the difference.

[gentle rock music]

There's not a great deal
of discernible difference.

- The best way to tell
is using your nose.

- There's a difference.
- There's a difference.

- Much. There's a difference
in the smell, most certainly.

That, actually,
that one does smell of oil.

[Simon chuckles]

And that one smells
of cheese and onion.

But they're both crisp.

I mean, they're both crisp
and they both taste okay.

But I'll give you it,
that one smells of oil.

Well, we're passionate
about crisps.

We notice the difference

and we care about
the difference.

[upbeat indie-rock music]

- As well as helping
to preserve the crisps,

the nitrogen also acts
as a cushion

to protect them on their
journey to the shop's shelf.

It's been less than 4 1/2 hours

since I saw the spuds
being loaded into a truck

and now my crisps are
heading for distribution.

They've got to move more than
five million bags of crisps

all over this gigantic
site every day,

so forget about conveyor belts.

[upbeat electro-rock music]

Welcome to the crisp monorail.

This computer-controlled system
snakes through

the factory's
distribution center

connecting the packing hall
with the loading bay.

The distribution center
is monstrous,

more than 37,000 square meters,

larger than the Houses
of Parliament.

And from the control room,

Chris Neville can track
every single packet.

From this nerve center here,

we can see all the pallets
moving around the site,

which ones are going
to which customers,

and we can also
track the vehicles.

This truck is going
to a customer

and do you see the blue arrows?

It should arrive
in about 40 minutes.

- The trucks not only deliver
crisps to supermarkets,

many will also then
collect potatoes

on the way back to the factory

and Chris knows where
they are at every stage.

So just take a potato, right?

One potato.

From the moment it leaves
that farm's gate,

all the way down to here,

and then through every process

and then back out again
as a cooked and flavored crisp,

all the way out to the shop
where I can buy it,

you track it minute by minute.

Correct, yes.

George Orwell predicted this.

[majestic rock music]

On average,
a truck loaded with crisps

will leave
this distribution center

every six minutes.

From the factory in Leicester,

they'll be delivered
all over the UK,

where the biggest crisp eaters
are in the northeast.

And amazingly,

some will even make it
to the Costa del Sol

to satisfy the ex-pat market.

Raw potatoes that were
on a farm just this morning

could be being eaten
as crisps as soon as tomorrow.

It is quite remarkable

that you can put a simple
potato in one end of a factory

and it'll come out as a sealed,
flavored bag of crisps

the other end of the factory
in just 35 minutes.

Not only that,

the engineering
and the precision

that you need to do it
five million times a day.

But do you know
what really surprises me?

It's that we actually eat
that many crisps.

Right, I've done my training,

the only thing left
is to load my crisps

on the back of a truck.

Chocks away, Ginger!

[majestic rock music continues]