Original subtitles

Whether you're enjoying your favourite food...

- Going on a date...

- ..or you just enjoy the taste,

as a nation, we can't get enough of mints.

In the UK we consume around 19,000 tons of them every year.

So I've come to see how they're made

at a factory that produces 32 million of them every single day.

I'm Gregg Wallace.

This may be the best smelling factory I've ever been in.

And I'm following the production of a mint from a sugary avalanche...

That's snow!

You've made edible snow.

..to a super strong sweet...

Whoa, look at that! That is one tough mint.

..while unwrapping one of the biggest mysteries

for sweet lovers everywhere.

The holes, do you kind of pull your finger through it

to make the hole in the middle?

- If we made them all like that, Gregg, we'd never sell any.

- I'm Cherry Healey.

I'll be finding out how you extract super strength oil...

My mouth is on fire.

That is so powerful!

..from mint leaves.

Control room. Do you read me?

And I'm on a mission to find out how you get from this...

..to the purest white sugar.

The effort that goes into making sugar is mind-blowing.

- And historian Ruth Goodman...

..is unearthing the strange but true story

of the world's first minty mouthwash.

- Oh, my goodness. This is strong stuff, isn't it?

- On this site, they produce a staggering

2.1 billion mints a year.

And I'm going to reveal just how they do it.

Welcome to Inside the Factory.

This is the Nestle factory in York

covering an impressive 230,000 square metres.

That's the same as 32 football pitches.

This massive factory produces 650,000 tonnes

of chocolates and sweets every year,

made up of 180 different varieties.

But today it's the turn of something fresh to take the spotlight.

I'm following the production of a mint

that's famous for the hole in the middle, the Polo.

These little holey wonders have been produced here since 1948,

and the team churns out 96 million minty morsels every week.

The process starts as it always has,

with a great big delivery of sugar,

all for my sweets.

So I'm meeting up with process engineer Mark Allen.

Mark. - Hello. - Hello, sir.

First things first. Goods in, right? - Yep, that's correct.

- So how much sugar do you use every day, roughly?

- 28 tonnes.

- Every day? - Every single day, yeah.

- Where's it from, do you know?

- It's from Norfolk, from sugar beet.

- Oh, it's beet sugar. It's not cane sugar.

- That's right, yes. - Can I see the sugar?

Can I get a sample? - Yeah, course you can. Yeah.

- May I?

Sugar produced from cane and beet is chemically identical.

- So if you just pull that down, it'll flow out.

- But only beet is grown in the UK,

so the factory can rely on a steady flow of sugar grown nearby.

Oh! It won't stop coming out.

- There you go. - Mark? - Yep.

- That looks very much to me like sugar I'd have at home.

- Yeah, granulated sugar.

But you can have different colour grades.

- Sugar has a colour grading?

- It does, yes. - Oh, blow me, I never knew that.

Stories about white sugar, there's lots of them.

But stories about brown sugar - dem are rarer.

OK.

It's the sucrose in sugar beet that gives it the white colour.

And here at the factory,

they use the whitest sugar they can get their hands on.

- It has to be the whitest of white,

so it makes our sweet nice and bright.

- Have you ever worked out how much sugar you use in a year?

- Yeah, it's about 3,000 tonnes.

- Crying out loud.

That's an extraordinarily large amount of sugar.

- If it was stacked in one-tonne blocks,

it would be roughly 3,000 metres.

- Yeah, but what's 3,000 metres?

- It's about 30 Big Bens on top of each other.

- You guys with your stats! No-one should have worked this out,

you know that. - I do.

- If you have a cup of coffee, do you ever just get a spoonful?

- We do.

- I would.

No time for a break yet,

we need to get this crystal white sugar unloaded,

with the help of the wonderfully named driver, Greg.

- Do you want to put the pipe on?

- Yeah, I don't mind lending a hand. Yeah!

Did you always want to be a fireman?

As the sugar is unloaded

at a rate of ten tonnes an hour into this whopping 30-metre silo,

the production of my mint is under way.

Come on!

It will take three hours to empty the other Greg's tanker.

We use regular sugar granules all the time

in our tea, on cereals or for baking.

But how do you extract something so refined from a plant?

Cherry is BEETing a path to find out.

CHERRY: My mission begins at this 160 acre metropolis in Norfolk.

This is the largest sugar refinery in Europe.

It processes a whopping 3 million tonnes of British beet every year,

that's refined into nearly 25% of the sugar we use in the UK.

But how on earth do they turn one of these

into the purest, whitest sugar?

BEETS me, but refinery manager Chris Flynn...

Hi, Chris. Lovely to meet you. - Hello.

- ..oversees the extraction of the sweet stuff

from these gnarly root plants.

Why does this vegetable in particular

have such high sugar levels?

- Sugar beet has a two yearly life cycle,

so the first part of its cycle involves storing sugar.

So we actually swoop in at the end of its first year

and extract the sugar for ourselves.

- So a bit like a thief.

- Exactly. - So this sugar beet has very diligently

been getting lots of sugar,

and you come in just when it stocked up the cupboards, and you raid them.

- That's right.

- After harvesting, they're washed, chopped and loaded

into three enormous barrel-like machines called diffusers.

Each hour, 280 tonnes of beet

are tossed in 200,000 gallons of 72-degree water,

the perfect temperature to extract the sugar.

And when 60 minutes is up,

the water has absorbed the sugar molecules and excess beet residue,

which is purified and evaporated to make a brown sugar-packed syrup.

- We call this thick juice.

- So that is sugar beet juice. - Yeah.

- So, what happened to the thick juice?

Where are we now?

- We are in the refinery part of the factory,

and we are converting our thick juice into white sugar

in these large vessels called vacuum pan crystallisers.

- How can I help?

- You can start the process off if you'd like. - Yes, please.

- If you tell the control room from this walkie talkie

to charge pan three, that will happen.

- Control room? Do you read me?

Charge pan three. Go!

I added the go bit. Was that wrong?

- That's fine.

- The extraction of sugar crystals forms the thick juice.

It happens here in six 45,000-litre pans.

And it's a surprisingly steamy business.

It's so hot in here, it's like a sauna.

Why is it so hot?

- What we're doing is we're actually boiling our thick juice

to remove the water

so that we can get the sugar crystals to crystallise.

- But it can't get too hot inside the pans

or the sugar crystals would be ruined.

So it's cooked in an unusual way.

- You do this under a very low pressure,

so all of our pans are connected to a vacuum system,

and the vacuum actually sucks out all of the air inside the pan.

- The vacuums reduce air pressure to a level

that allows the thick juice to boil at 70

rather than 100 degrees Celsius.

Why do you do that? Why not just boil it at 100 degrees?

- The main reason is actually because the hotter our thick juice is,

the more colour it forms,

and we are trying to make the purest, whitest sugar.

So by doing it at a lower temperature,

we're able to do that easier.

- The juice thickens in the pans for three hours.

As the water evaporates,

it forces the sugar that is dissolved in it

to solidify into crystals.

Kind of.

I don't want to be rude, but you took a lot of effort

to make sure it wasn't brown,

and, um, it's really, really, really brown.

- Yeah, the crystals themselves that are in there

are a perfect, pearly white.

- What is the stuff that you don't want?

- So it's leftover liquid from the first boiling process.

It will go for some further process and eventually end up as molasses.

- Molasses, or black treacle, is often used in baking,

but we are not making a sticky toffee pudding.

So what you really want in here is the white crystal sugar.

- That's right. We just have to separate out the liquid that's left.

- You're gonna need some very small tweezers.

- No, we've got some big machines called centrifuges in front of us,

which do that for us.

You can start one if you want.

- Can I kick it off? - Yeah.

If you just want to push this button here. - OK.

Three, two, one.

There it goes.

The centrifuge is like a high-tech washing machine.

It spins the thick syrup around at a rate

of 1,050 rotations per minute,

and a screen of stainless steel mesh with 0.8 millimetre holes

sifts out the brown liquid, leaving just solid sugar crystals behind.

Look at that.

Why does it need to be so fast?

- It really needs to generate a lot of force

just to separate the sugar from the liquor in there.

When they're spinning at their top speeds

and they're fully charged with sugar,

they've got the same amount of energy

as a family sized car travelling at 200mph.

- Nothing about this process is small.

- No, it's all pretty big scale.

- These four huge centrifuges take about three minutes

to turn the thick liquid into snowy white sugar crystals,

churning out a whopping 1,700 tons of sugar every single day.

But after all that spinning, it still contains about 1% water,

and removing that requires one more magical machine.

Wow!

Oh, my goodness!

It is as close to Willy Wonka's factory as I think I've ever got.

That is a sugar waterfall.

- It is.

So this is our granulator.

What we've got is sugar coming in one end wet

and travelling down the drum with heated air

being blown back through it.

That air is picking up the rest of the moisture

that's left in the crystal from our centrifuges.

And at the end of this, out comes powdery white sugar.

- Once cooled, it's stored in a silo for a minimum of 48 hours

before it's finally ready.

This whole city-like factory is to get this.

- Yeah. That is the sugar that started in the beet.

- Amazing.

The effort that goes into making sugar is mind-blowing.

Every week, this vast refinery

produces up to 11,500 tonnes of white sugar,

and three truckloads of it make their way

to Gregg's factory just for his mints.

GREGG: At the factory, 28 tonnes of beet sugar

is pumped into a mega silo,

and then piped to the extruding room,

where I'm going to meet up with Mark.

This space is huge.

At 16 metres high, it could fit a three-storey building in it.

Mark. - Hiya, Gregg.

- Mate, this seems massive for a tiny little mint.

What goes on here?

- Well, that sugar that was pumped into our silo earlier, Gregg,

that's transported to a mill at the top of this room.

- Where exactly is the mill?

Is it that one there on the left?

- It's the one just behind that one on the left.

- Well, it looks like the overweight robot.

What does the mill do?

- Well, the sugar in its current state is 0.5 of a millimetre.

It isn't refined enough.

And we need to mill it even further

to get it down to 0.1 of a millimetre.

- What's that like a fine, fine flour?

- It's, yes, because it's not refined enough,

it will create a grainy product,

and it won't stick together properly.

So we need to refine it down even further to make a strong product.

- So is that a bit like a pepper grinder,

it's grinding down the pepper into a dust?

- That's correct, yes.

It just helps keep the product smooth

and taste better in your mouth.

- As soon as my sugar is milled to a particle size of 0.1 millimetres,

it drops down to combine with a plant based lubricant

to stop it sticking in the pipes as it moves around the factory.

Then it's pumped to an extruder,

where it's also mixed with a binding agent

made from corn starch, water and glucose syrup.

Fabulous. All right.

So we've got the fine milled sugar.

We've got the binding agent.

Now what's happening?

- Well, inside our extruder,

there's an Archimedes screw that oscillates, and rotates

and mixes everything together.

- My sweetie mixture is spinning at a rate of 250 rotations per minute

and is heated to 90 degrees,

until 45 seconds later,

something magical appears.

That's snow!

You've made edible snow.

- That's what we call our flakes.

- # Snow is falling... #

- Two tonnes of these sweet, warm snowflakes,

or dough, are forced out of the extruder every hour.

You made hot snow!

Which is enough to make a whopping 1.5 million mints.

I would never have imagined that those little mints

start off looking like this.

Isn't that odd?

It's really light and fragile,

but it's almost like a hot, sticky powder.

- It is, yes.

- It's a little bit like the inside of a chewy mint.

The big question, right, the holes.

So once you get it like that, you kind of

force your finger through it to make the hole in the middle?

- I think if we made them all like that, Gregg, we'd never sell any.

But we will show you later.

- My sticky dough flakes now ski uphill on a three-metre conveyor

before tobogganing into another of Mark's marvellous machines.

- This is our granulator, Gregg.

This is where our dough comes down and we create our smaller granules.

- You're breaking it down into even smaller bits.

- We are, yes. - Why would you do that?

- It's how it makes the product stronger.

We've just stopped our machine, so I can show you if you like.

- Yeah, yeah, please.

The granulator is a large metal sieve...

Ah!

..with four-millimetre holes.

A mechanical arm rotates 90 times a minute,

crushing my dough flakes into smaller granules.

It's like little sweeteners.

Why do you still want lumps in it?

- Well, think of our dough as a brick wall.

You need your bricks and you need your cement,

otherwise, you can't make a good, strong wall.

So we make the granules the different sizes

to help create that strong mint.

- So my sweets are a feat of sugary structural engineering.

That's a brilliant explanation, I perfectly understand.

I've just never considered a mint like a brick wall.

- Well, you learn something new every day, Gregg.

- # All in all you're just another brick in the wall. #

- My building blocks of sugar have been reduced to granules

smaller than four millimetres

and are pumped to the drying room,

into an even bigger stainless steel machine.

What?!

Tending to this monster is process and product expert

Alison Stancliffe.

Alison. Do you know what it looks like to me?

It looks like an enormous great drill.

You know, the thing that bore out the space for the Channel Tunnel?

- Yeah. - That's what it looks like to me. Look at it.

Help me. What is that?

- So this is a dryer.

So it's really important

that we get the right moisture content in our sweets.

Because if it's too wet, it won't press to form the right shape.

And if it's too dry, it will be quite brittle.

And if you think about how you eat the sweet,

we want it to last, be nice and smooth

and last a long time in your mouth.

- So you spend all your time getting it

as sticky and as gooey as you can.

And then you try and take most of the sticky and the gooey out.

- Absolutely, cos it makes the perfect sweet.

- Well, it makes...in your opinion.

I like humbugs.

Can I have a look in there? - Of course you can.

- Oh, I see!

Ten tubes are encased in this eight-metre long dryer.

As it slowly rotates,

each tube collects the sugar granules that fall directly

into the dryer from the granulator upstairs.

Air that's been heated to 55 degrees

is pumped into the dryer from the opposite end.

The granules tumble towards the hot air through the tubes,

which are positioned at a precise angle of 3.83 degrees,

controlling the speed and ensuring that they dry thoroughly.

When my batch reaches the end,

the moisture level in the granules should have dropped

from 0.9% to 0.5.

And after 22 minutes, it's time to see if the dryer has done its job.

- There's our sample of granules.

- So we're off to do one of 30 moisture checks

the factory must do every day.

- Right. We're going to go and get that measured now.

- This machine here measures your moisture.

- It does. - Come on in, shall we? - We shall.

So what we do is we put 5g of granules on the tray.

- The machine weighs it.

Then the metal plate below the sample is heated by infrared waves.

- It extracts the moisture out of the granules

at a temperature of 105 degrees C for two minutes.

They need to be less than 0.5% moisture to make our mint.

- Then it's weighed again, and with some clever maths,

we can work out if my sugar granules

have the correct percentage of moisture.

If my sample fails this test,

every granule of my batch must be recycled,

and we'll have to start all over again.

To pass, it must contain less than 0.5% moisture.

- And you can see there, that's finished. It's 0.33.

- Ah!

Well done.

Can I see our sample?

- 'Course you can. - Cos I saw it when it went in.

Cos the last time I saw this, it was, it was actually quite moist.

Oh, wow.

Well, that's dry like salt.

Right.

Now, we now know that our dried mix is dry enough.

- Yep. - So what do we now do?

- So now we need to add some mint oil,

and then we have to make it into the sweets.

- Brilliant. We're going to make it wet again. - A little bit.

- You take dry things, make it wet,

and then work really hard to make it dry again,

to make it wet again, after.

- Something like that. - Are you sure you thought this through properly?!

Allison assures me that my sugar is perfectly dry

and the right texture to provide a strong structure for my mint.

So it's finally ready for the all-important flavour.

We all know what mint tastes like,

but how do you get that strong flavour from a little green plant?

Cherry has gone to find out.

CHERRY: Many of us love mint.

It grows at a prodigious rate in our gardens,

but cultivating it in the UK as a commercial crop

is surprisingly difficult.

To find out why, I'm meeting Joe Colman

on his 100-acre peppermint farm in Hampshire,

one of only a handful still growing it here.

Hi, Joe. Lovely to meet you. - Hi, Cherry. Lovely to have you here.

- I really appreciate you're wearing a mint-coloured shirt.

- Thank you. Well, I thought it would be rude not to.

- So is this the same mint that I grow in my garden?

- Cherry, no, this is peppermint.

So what you've probably got in your garden is spearmint.

- There are more than 600 varieties of mint.

Garden spearmint grows well,

but delivers a milder flavour than the more picky peppermint,

which contains 40% menthol,

the chemical compound that gives it its zingy taste.

What are you going to make with this peppermint?

- So we can do, really, two things from it.

We can take the leaf and make it into nice peppermint tea,

but we can also extract it for oil.

- The oil can be added to chocolates and fragrances,

but the variety of peppermint that Joe farms to get it,

Black Mitcham, is hard to grow.

Why is it so tricky?

- You've got a whole combination of factors.

You've got a mint plant that roots about an inch into the soil.

So it's very temperamental if the conditions aren't right.

- Plants with short roots

can only absorb water near the surface of the soil,

which dries out much more quickly than deep soil,

so they need to be watered a lot.

Why have you chosen to grow a mint that's really difficult to grow?

- It's the smell and the flavour that you get from Black Mitcham.

So if you rub that flower head at the top,

you get this brilliant, strong smell.

But if you rub the leaves,

you've got this different kind of sweeter,

lighter notes that come through.

And that's what makes Black Mitcham so special.

It's the whole package that this plant gives us.

- But is that hit of minty fragrance worth it?

And guess what?

This high-maintenance plant has to be harvested carefully, too.

So I'm lending a hand.

All aboard Derrick Oliver's multistorey machine.

Holy Moley.

It's like an apartment block.

- Give it a good slam.

- The peppermint has already been carefully cut

by a tractor-drawn mower.

Next, it needs to be picked up and processed within 24 hours,

or too much of the mint oil from the flowers and leaves will evaporate.

It's the first time I've seen a tractor like this.

Do you call it a tractor? - It's a forager.

- It's a forager. - A forager.

- It's not a combine harvester. It is not a tractor. - It's a forager.

This machine would normally be used on grass,

but we're using the same technology,

just that we're not chopping the mint

as fine as you would chop grass.

- Are you saying that this is a gigantic lawnmower?

- Well, not really, no.

- Derek's forager gathers up the mint into a drum

where 40 knives chop it into 4cm pieces,

before shooting it out into his trailer.

That's it? It's like a mint smoothie.

- Yeah, it's a bit like a mint smoothie. Yeah.

- It takes just 30 minutes to cut and collect three tonnes of peppermint.

And so the valuable oil can be extracted as quickly as possible,

it's all done on site by Joe's farm manager, Ian Margetts.

Ian, lovely to meet you. - And you, Cherry.

- So, where do we off-load it? - Well, that's the thing.

We don't have to off-load it,

cos these trailers have got a special trick up their sleeves.

Just watch this.

- The mint never leaves this high-tech trailer.

Instead, a pipe connected to it blasts the herb

with scorching 170-degree steam.

And the leaves luxuriate here for four hours.

So how does it work?

How do you cook mint in a lorry?

- The peppermint plant that you brought in,

each one of those leaves, the underside of it

is covered in little oil capsules.

You can't see them with the naked eye. And they contain the oil.

We use the steam to break them down, and it turns it into a vapour.

- The mint vapour, or gas, then passes through a condenser,

is cooled and turns back into a liquid.

A bit like when steam from your kettle hits a cold window

and turns back into water.

Look at this. It looks like a mad science experiment.

- Pretty much is.

- Except here, what we end up with is pure peppermint oil.

- Would you like to try a little bit of the menthol?

And then if you just put your tip of your finger in there and taste it.

But it is very, very strong.

That's plenty. - It's not mucking about, is it, this stuff?

Cor!

Oh! Ooh!

My mouth is on fire.

My eyes are starting to water.

That is so powerful.

- It is. You're getting a real hit of menthol.

You've got 40% menthol in there.

And that is why you don't use peppermint in your new potatoes.

That's why you use garden mint, spearmint.

- Nearly half of peppermint oil is made up of menthol,

so you may not want it on your spuds,

but it's the perfect pick if you need a little to go a long way

when making minty products on a large scale.

I mean, it's magical stuff.

- It really is.

- So maybe pernickety peppermint is worth the hassle after all.

GREGG: I'm 30 minutes into production,

and my sugar granules have been tumble dried

to the perfect moisture for mint making.

Oh, wow.

Well, that's dry like salt. - Yep.

- We're ready for the essential taste bud tingling ingredient.

So I'm heading to the mint room to meet quality manager Rachel.

Hello. Wow.

That is extraordinary!

That's like walking into an air freshener.

I mean, that is a cloud of mint.

- Yeah! This is where the peppermint oil is stored.

- These 180-kilo barrels of concentrated peppermint oil

come from America, where most of the world's mint is grown.

I don't suppose you know, do you,

how many individual mints would a barrel make?

- Each barrel can make up to 40 million sweets.

- Extraordinary.

Hang on a minute. How much of those do you go through?

- I go through about three barrels every week,

and each barrel costs about £6,000.

- HE GASPS

Each one of those drums is about six grand. - That's it.

- This hefty price tag is because

it takes a whopping 200 million mint leaves to make just one barrel.

So what are you going to do with these barrels?

- We're going to put a pump in the barrel

and the barrel is going to pump the oil into a holding vessel here.

This is then pumped into the holding tank in the press room,

where it's added to the sugar mix.

- Is there any way that I can help you connect it up?

- Yeah. Let's give it a go.

- Do I have to get dressed up like you?

- Yes, you do, I'm afraid.

Peppermint oil is extremely hazardous in big quantities.

It's also a skin irritant, so you need to wear protective gear.

- Do you reckon I might be putting too much on my roast lamb?

- Only in large quantities, Gregg. Don't worry.

- Well, no, I do have lamb in large quantities.

I obviously need to cut back on my chops.

But the level of essential oils in the concentrated mint blend

is so high that it could harm my soft TV presenter's skin.

So I do need the right gear.

I've got, like, a space helmet and an abattoir smock.

I'm like Darth Butcher.

- That's a new superhero. - Right.

Now, what do we do?

- We're going to put this pump into the barrel,

and then all we need to do is press the button, and it's good to go.

- I got dressed up like this to press a button?

I got dressed up like this to press a button?

- I'm afraid so, Gregg. - One of us is daft.

- We can't be too careful. - Right. OK.

At no risk of irritation, to my skin at least,

a 160-centimetre-long pump uses five bars of pressure

to suck up the oil.

Oh, it's massive.

- Sorry, Gregg.

And put that in there.

- £6,000 worth of mint?

- Absolutely. - You ready? - Ready.

Just release the air.

- And now it's making the sound like Darth Vader.

- That's it. The oil going into the holding vessel,

ready for production.

- I'm pleased, at least I didn't get all dressed up for nothing.

Right. Can I take these clothes off now, then?

- I'm afraid not, Gregg. We need it for the next bit.

- All right.

So, do they deliver the holes soon?

- Here we are. - Up there? - Up here.

- My mint oil is flowing towards the production line

and its first stop is upstairs

at the intensely fragrant mixing zone.

This whole place has just got an almost pine-like smell to it.

I mean, so much, it almost makes your eyes water, doesn't it?

- Absolutely.

- It may be the best-smelling factory I've ever been in.

- I'll take that, Gregg.

- The mint oil doesn't just smell strong,

it has an intensely overpowering flavour,

which is why it has to be added very carefully to my granules.

- So here we've got 500g of sugar granules from the dryer.

That equates to about 340 mints.

How much peppermint oil do you think we need to put in the bowl?

- Well, I'm guessing, like, one of these.

- Not quite.

- Just 1.3g flavours this whole bowl of sugar.

Yeah, that's a ludicrously minuscule amount, isn't it?

I mean, it's hardly, like, hardly there.

In fact, so little is needed,

only 0.29% of each individual mint is made up of peppermint oil.

That is a strong peppermint. - And that's what we want.

- That may be one of the strongest flavours I've ever experienced.

- Some strong stuff there. - Absolutely.

Good job I'm dressed as a superhero.

Now, 104g of this powerful peppermint

is piped into ten giant mixers,

along with 50kg of my sugar granules

sent into each one directly from the dryer.

Right. So if I could open up the mixer, what would I see?

- There's metal paddles which move the ingredients together.

- So how long does that take?

- Only 90 seconds.

- That's quick. That's ridiculous.

Why so fast?

- Because the peppermint oil is so strong

and the flavour is so intense,

and the granules pick up the flavour really quickly,

it doesn't take long at all.

- So how many mints would that make, do you know?

- That would make just under 41,000 mints.

- And you've got ten of them going at once?

- And we do that 80 times a day.

- So how many mints are you making a day?

- That's just about 32 million sweets.

- 32 million individual mints every single day.

- That's right.

- You don't really put holes in them, do you?

- We'll find out in the next step.

- Surely they can't keep me in suspense for much longer.

Most of us have had a mint to freshen our breath,

but a quick gargle with mouthwash works well too.

But that minty liquid in your bathroom cabinet

has a very murky history, as Ruth has been finding out.

RUTH: In 1864, the English countryside looked idyllic

but didn't always smell that great.

The whiff was caused by raw sewage that was being dumped into pastures,

making the grazing cattle ill.

Farmers tackle the problem with carbolic acid

extracted from coal tar,

which had helped to eradicate rot in wood caused by bacteria.

And an influential medic got wind of their incredible results.

British surgeon Joseph Lister heard that carbolic acid

had completely neutralised the foul smell,

and moreover, that the cows were no longer getting sick.

And he wondered, could this also work in his operating theatre?

Lister's patients were dropping like flies.

Their infected wounds gave off an offensive odour,

and he deduced that the cause, as with the sick cattle,

could be bacteria.

So he sprayed his operating theatre with the same

bacteria-busting carbolic acid.

And deaths more than halved.

News of Lister's success spread, and in 1879,

American chemists Joseph Lawrence and Jordan Wheat Lambert

saw the potential for a milder anti-bacterial product

that could be used in the home.

Using alcohol instead of carbolic acid as a base,

they gave their new product a fresh smell by adding mint,

eucalyptus and thyme.

They called their concoction Listerine

in honour of their hero, Joseph Lister.

Medical historian Professor Jamie Starke

has researched how the new product was pitched to the public.

- In the early days, as you'll see from the advert,

it was really billed as a catch-all disinfectant.

It could be used to prevent infection of cuts and wounds

to keep your teeth and mouth healthy, as a lotion after shaving,

but they also claimed it could be used to treat dandruff,

and it was used as a general

all-purpose household cleaner as well.

So, really anything and everything in the home that you could need.

- By the 1920s, the market was crowded

with competing household disinfectants and antiseptics.

So to stand out, Listerine needed a stronger identity.

And an advertising executive called Gerard Barnes Lambert

had a light bulb moment.

- He was brainstorming with his brother

to come up with things which Listerine would be useful for.

And on this list, they picked out on a very obscure word for bad breath,

halitosis.

And that was the one thing which they thought they could

bill Listerine as being distinctive in treating.

- The word "halitosis" has its roots in Latin and Greek,

so it sounded suitably serious.

- People had always had bad breath,

but halitosis was one thing which they could make sound

medical and scientific.

They could bill it as a medical condition which needed addressing.

- And what better to help tackle this new-found disorder

than a mint-flavoured mouthwash?

How did they communicate this to people?

- They started a new advertising campaign

which billed halitosis as the central reason for buying Listerine.

So if you look at this one from the 1920s...

- Oh, my goodness.

"Halitosis makes you unpopular." - Yeah.

Absolutely. - "It is unexcusable. Can be instantly remedied."

Goodness. This is strong stuff, isn't it?

- It is. So they're really identifying halitosis, not just, I suppose,

as a medical condition, but also something which

it's your social responsibility to address. - Right.

I mean, one of the things about bad breath is that

if you've got it, you probably don't know you've got it.

Only somebody else can smell it. It's hard to smell your own breath.

- And in their adverts, they were very clear that people

wouldn't necessarily be aware that they had it,

and even that their friends would be too kind to them.

They wouldn't actually mention it.

- And young women were specifically targeted

by these mad men of mouthwash

at a time when they were particularly vulnerable.

- In the 1920s, in the aftermath of World War I,

there was very widespread social anxiety about lots of young women

who might be widowed at a young age. - Less men about.

- That's right. Lots of men have been killed in the trenches,

and some of their advertising is very heavily gendered.

- "Often a bridesmaid, never a bride."

Jeepers! - And Listerine, like many other products of its day,

tapped into this really fundamental and deep-seated anxiety

that you would have a society with lots of ageing spinsters

who had lost the opportunity to start a family,

to be at the centre of their domestic life.

- I find this really, really distasteful.

I'll be honest. - Yeah. It is.

Yeah, absolutely.

And, of course, if you were at risk of these disastrous consequences,

there was a very easy solution.

- Of course, Listerine.

Transforming Listerine from an all-purpose antiseptic

to a product that could eliminate halitosis

and save people from terrible loneliness

was a breath of fresh air for the company's balance sheet, too.

These advertising campaigns boosted the company's profits by 60 times

in just five years.

But the man who inspired the product was apparently less than impressed.

For while Joseph Lister's scientific breakthrough

would go on to save untold thousands of lives upon the operating table,

his name was attached to a cleverly marketed product

that treated a much more minor complaint.

GREGG: Back at the factory in York,

and my mints are 33 minutes into production.

The concentrated oil and dried sugar granules have been blended together.

That is a strong peppermint!

And that minty mixture is on its way to the press hall,

where I hope I'll finally find out

how this famously holey sweet is made.

- And here we are in the press hall.

- What do you want to show me, Rachel?

- The peppermint oil and sugar mixture that we saw in the mixers

falls down into those two cylinders there,

that look a bit like trouser legs.

- Yeah, it looks like a robot's trousers.

Each metal leg has a sieve inside to make sure

my falling minty powder mix is lump-free

before it's fed into a mysterious revolving carousel.

So could this be the moment of truth?

How do they make the mint with a hole in it?

Do you mould your mint to make the hole

or do you punch a hole in it?

- We mould it. - Yay!

I thought you might.

You don't have to make holes at all, do you? - We don't.

- All right, yeah, can you show me how it's done?

- Gregg, do you want to rotate the punches,

and I can show you how it replicates the process?

- Yeah, come on, then.

- So as you can see, we've got a punch on the bottom as well as the top,

and it's that top punch that presses down on the powder

and moulds it into the mints

and creates the iconic branding on the sweet.

- We need just 1.5g of my powder mix to make one individual mint.

- The powder's quite sticky,

and so it's able to be compressed into that mould

and create that shape.

But it's so sticky, we have to lubricate the punches once a shift,

to make sure the powder doesn't get stuck on the stamp.

- So every six hours, a food-safe lubricant

makes the moulds non-stick.

Well, that's great. I'm turning the handle,

and they're going up and down.

- You're not doing it fast enough, it's 78 rpm usually.

- All right, I'm doing my best.

When it's cranked up to full speed,

the punches exert huge downward pressure

to crush any remaining rough granules in the mix.

So the force of that is enough to turn it from just a powder

into something shiny and solid?

- That's right. About eight tonnes is required to compress the mint,

which is the same weight as a ship's anchor.

- Hang on a minute, hang on a minute.

Each of those little mints has been pushed

with the pressure of eight tonnes.

Eight tonnes? - Yep.

- Exerting this massive pressure creates friction

which warms, smooths and compacts the mints,

so they are no longer sticky

as they drop from the press

onto a 60-metre-long system of conveyor belts.

Whoa!

That's a river of mints.

Look at that! - A never-ending river.

- # Hold back the river, let me look in your eyes

# Hold back the river so wide

# And stop for a minute and be by your side.

# Hold back the river, oh! #

- I almost want to row down it.

That's an impressive sight, isn't it? - It is.

- So, how many is coming past my eyes?

- We've got ten presses in here,

each making 3,500 sweets per minute.

That's 35,000 every minute.

- 35,000 a minute.

You won't miss one, then, would you?

Am I allowed to? - Go on, have a taste.

- They're still warm.

It feels like I'm having one from a packet I've been sat on.

- We've just had one hot off the press,

so that's why it's still a bit warm.

- Can we stick another one in the fridge?

Hang on a minute. Why would you make it into a ring

and not just, like, a solid mint?

- So the mint is inspired by the US brand "Life Savers".

They replicate a life-saving rubber ring.

- Is that right? - That's right. - Brilliant!

Where does the word "Polo" come from?

- So the name "Polo" comes from polar,

which references the fresh taste and flavour of mint.

- They're having a giggle with that name, aren't they?

- No, that's facts.

- Who signed off on that one?

Is that right? Now, can we send them to the wrappers now?

- Not just yet. We've just got to do some quality checks

before we're comfortable sending them to the wrappers.

- 23 randomly picked sweets are checked every hour...

- Do you want to take a sample and we'll go?

- Grab some from that one.

..to make sure these mighty little mints

can retain their newly formed shape.

- This is our texture analyser,

which is measuring the strength of the sweet.

The perfect mint should be able to withstand

6kg of pressure.

- That's quite a bit.

- It needs to withstand the pressures of the wrapping machines

as well as being transported to the supermarket.

- So what's it going to do? Squeeze it?

- That's right. - And then record the amount of pressure? - That's right.

- But what happens if your mint can't withstand six kilos of pressure?

- Then that's a big problem, and it can stop production.

It means we have to alter the consistency of the powder

back at the beginning of the process.

- Right, so this is a big challenge.

- So if you want to put the sweet there

in between the metal plate and the rods. - Like that? - That's it.

Close the plastic cap, and then it will do the rest.

- # I've got the power. #

- Let's go.

Strong mint, strong mint, strong mint.

Whoa! That one broke at nine!

This is fun.

Right, let's torture another one.

Let's see what... The record is nine. - Nine.

Can we beat it? - Can we beat nine?

- Yes, it did, 9.32.

- Yeah, look at that!

That is one tough mint.

- So the fact that it goes up to 6kg shows that we've got

good distribution of particle size within the sweet.

- All that milling, binding, mixing and drying has paid off.

And my particle size is perfect.

I knew it would be.

That is fantastic.

That is one of the best tests I've ever seen in any factory ever.

But there's one more test that I want to try.

There's a game, apparently, where you can see how long

you can make the mint last in your mouth. - Right. OK.

- Up for a challenge? - Absolutely!

- Go on, then.

One, two, three.

Careful.

I have to be careful.

Right, you do that. Where am I going now?

- To the wrapping hall! - Wrapping hall.

- See you, Gregg.

- Mint has a very distinctive taste.

So why aren't all minty products exactly the same?

Cherry's been finding out

just how adaptable this humble herb can be.

CHERRY: So many of the groceries in our shopping basket

pack the zingy punch of mint freshness.

So, how do manufacturers make so many different flavours?

Omega Ingredients in East Anglia creates flavourings

from natural ingredients to provide the tastes and smells

for hundreds of products.

And the man who sniffs them out is master flavourist Steve Pearce.

Hello, Steve. Lovely to meet you. - Cherry, nice to see you.

- So, how do you become a master flavourist?

- Well, Cherry, it takes a bit of time.

If you think that there's roughly about 12,000 materials

identified as being responsible for the aroma and flavour of food,

there's no short cut to this.

You've got to taste.

You've got to put things in combination and work with them.

You've got to smell.

- Have you insured your nose?

- Yes, it's insured for a lot of money.

Three million pounds. - Three million pounds!

Steve's sensational senses have created minty essences

for chocolates, chewing gums and mouthwashes.

And that's not easy because the ingredients

that make up the flavours of our favourite products

are surprisingly complicated.

- Peppermint typically is around about 150 components in there

that lead to the degree of fruitiness, sweetness, sharpness,

floral character, and they're all important

to having a quality mint flavour.

- So when I have something that tastes of mint,

I just recognise that mint flavour.

But you're saying you have to break that particular flavour

into its components? - Yeah.

- Is it as complicated as, say, making a new perfume?

- This is far more complicated than making a perfume.

For one thing, we're working entirely with natural materials,

and most fragrances are made almost entirely of artificial materials.

- Today, Steve will be helping me to conjure-up something rather special.

I want to make my own flavoured sweet,

and the client brief is very simple.

I would like Cherry's Mints to take someone's breath away,

be really exciting, just like me.

- Of course, we can do that.

- 90% of what we perceive as flavour

actually comes from our ability to smell.

And that's down to a piece of tissue at the top of our noses

called our olfactory epithelium.

It's directly connected to the emotional

and memory centres of our brain,

which can decipher if we like what we're smelling.

So I need to sniff out the best minty flavours for my sweets,

and there's quite a few to choose from.

- First of all, there are 25 different varieties of peppermint,

and it grows pretty much all over the world.

- Different peppermints also have different levels of menthol,

the chemical component in the plant

that gives a fresh zing in the mouth.

And the intensity of the menthol depends on the conditions

in the country where it's grown.

- Menthol is much higher in the mints from India and China, so 85%,

whereas in the USA it would be 50% to 65%.

We're going to start with some Indian peppermint oil.

- That's lovely. Ah, it's gorgeous.

OK. - So we'll have some of that.

Then we're going to have the quality of the flavour

from some American Midwest, and that's very full,

so just be careful with that.

- Oh, I don't like that. - OK. - Ooh!

Too overpowering for the more

delicate flavours I want in my sweets.

Do you have to add menthol quite carefully?

- Yes, you do. So you might want a bigger hit, say, in a mouthwash,

for example, or a toothpaste,

or even a touch in chewing gum, but in your confectionery,

you may just want to control that a bit better.

- So we've created a mild minty liquid base flavour for my sweet

and are ready to add some additional complementary flavours.

To do this, we've been granted access

to Steve's inner sensory sanctum.

What is this magical place?

- So this is our applications lab,

and here are about 5,000 flavours to choose from.

- This is absolutely amazing.

There's almost every flavour under the sun.

Butterscotch, lemon, almond, beer, strawberry, hibiscus.

Look at all these! Tiramisu!

This is extraordinary. Did your team create all of these?

- Yes, we did.

- But I need to stick to the brief

and find some cherry flavours for my mint.

- It's here somewhere. - Oh, there's one. - OK.

- Ooh, that packs a punch.

This says, "I am here."

These complementary flavours boost the blend.

They're ingredients with the same chemical element,

and when they're brought together,

they become a match made in taste heaven.

- So if you smell eucalyptus, for example,

it has some common components with the mints we've already used,

so it will work well with that.

Thyme is complementary,

because we have those green herby notes in there already.

We might even add materials in here

to make it difficult for a competitor to copy your product.

- So you make it purposefully complicated?

- Yes.

- Finally, my unique flavour blend is added to sugar and water

and shaped into test sweets, which are then set before tasting.

So if this was a hit, what would I do now?

- So we'd make maybe a small batch in the lab or the factory.

We'd get some product out there for consumer research,

get some feedback,

and then it would be gung ho, tonnes being made in the factory,

shipping it around the world for manufacturing.

- So, has my mint got what it takes to be a global brand?

Or will Steve crush my sweet dreams?

- Cheers.

- It's not very cherry-ish. It's swamped.

- Yeah. The cherry flavour has been swamped by the sugar in the fondant.

Sweetness now drives the perception of flavour,

enhances some parts, depresses others.

It's quite minty.

So you've achieved that.

- Tick. - Yeah. Tick that out. Yeah.

- When shall I come and work for you?

I'm not going to give up my day job.

Goodbye, mint.

GREGG: At the factory, I'm 38 minutes into production.

My mints have been moulded into shape...

You don't have to make holes at all, do you? - We don't.

- ..and face the ultimate test of strength.

Whoa! That is one tough mint.

Now, they're flowing to the wrapping hall

on a 44m sky-high conveyor

that wraps around this 1,600 square metre space,

before dropping down to meet process operator Andrew Ross.

Hello. - Hello, Gregg.

- Wow.

Now, that's fantastic!

How many are going through here, Andrew?

- 155 tubes every minute coming through each one of these.

- How does that work?

- So this is one of ten wrapping legs that we have.

They're all fed from one main conveyor

from the press hall, where you've just been.

- Every hour, 2.1 million freshly pressed mints

circulate on the conveyor,

as they wait to be called to a hopper

that feeds the wrapping legs, or stations, beneath.

- An arm opens and sweeps in, sweeps off the main conveyor.

There'll be a few thousand come in at a time.

- Superb. Superb.

- As they come in, they come across this vibrating sieve,

which filters out any broken ones.

- How does it do that?

- Literally holes just the right size.

Just small enough that the full one can go across.

- Brilliant.

Once they've hurtled down these vibrating rapids,

the machine drops the sweets into a 23-lane conveyor,

forcing them to stand upright between metal walls.

They are marching, aren't they?

They are regimented, and they are marching.

- This is how we like to see it.

They're stood up into a row of 23 across here.

- Oh, each line is a tube?

- Each line of that is one tube line.

- As they parade down the conveyor,

the lanes become narrower,

before merging and then falling away completely,

leaving rows of exactly 23 sweets ready for wrapping.

- There's a little arm inside there that lifts each row of sweets up.

- And then what? First the foil and then the paper?

- Foil and paper go on together.

- A series of cogs feed aluminium foil

and the wrapping paper into the machine,

where a 12cm knife cuts them into 11x8cm strips.

Then both sheets are wrapped around the mints at the same time.

The foil is tightly secured inside the wrapper,

to keep my minty flavours locked inside the packet.

And then, what, do you stick it together...?

What's the glue?

- It's called Arabic gum.

- And what is that?

- That is the dried sap from two different kinds of acacia tree.

- The factory uses 40 kilos of this super-sticky sap every month.

Why don't you just have a pot of glue, like anybody else would?

- The mint oil is that strong that it'll degrade the glue,

and then everything will come unstuck.

- HE CHUCKLES

Naughty little mint.

Essential oils like mint can break down oil-based glues.

But my Arabic gum is water-based, so it won't budge.

A mind-boggling 1,550 securely wrapped rolls

come off the production line every minute.

May I? - Help yourself.

- I'm keeping these. I'm going to put them on my shelf in my office.

I saw that start as a lorry load of sugar.

The rolls are carried to the packing area,

where a hydraulic arm sucks up 24 rolls at a time,

and then drops them into boxes.

They're given a protective plastic covering

before riding a roller-coaster conveyor

to their final destination at the factory.

- So, here we are on dispatch.

- You still stack them by hand. - Still stack everything by hand.

- I've helped with loads of tests during my time here.

So as we count down to loading the lorry,

it's time to set Andrew one of my own.

Right. How good are you at numbers?

- I'm pretty good at numbers. - Are you? - Yep.

- You have the swagger of a confident man. Right.

How many boxes on a pallet? - 705 on one of these pallets.

- Right. How many pallets do you get in a truck?

- On each truck, you'll get 18 pallets, total.

- And how often does a truck leave here?

- We go through around about three trucks a day, every day.

- Really? - So that's just over ten million sweets per truck.

That's over 32 million sweets per day.

- Your numbers are really impressive.

- It's a lot of sweets.

- Andrew passes with flying colours,

and that mind-boggling amount of marvellous mints

are on their way to freshen the breath

of people right across the UK,

with Londoners loving them the most.

And they're also destined for shops across the world,

with Turkey as the biggest fan.

I've been amazed how hard they work here

to make every tiny mint just right.

From the micro-management of moisture in the sugar...

You make it wet, and then work really hard to make it dry again,

to make it wet again, after. - Something like that.

- ..to the colossal cost of making them minty.

- Each barrel costs about £6,000.

- And I finally found out how they put the holes in the middle.

- We mould it. - Yay!

Result.

But you know what I really love? That wonderful minty smell.

It's everywhere.