Original subtitles

I love Dublin.

In fact, I'm here every two years

for the Ireland-England rugby international.

And this city's hospitality is second to none!

And for me, it's the music - I just love it.

And where do they combine the two?

In one of the city's many pubs, of course!

There are over 750 pubs in Dublin,

and, along with a vibrant atmosphere,

they're famous for serving stout -

a dark, heavy-bodied beer with a dry-roasted flavour.

There's one Irish stout you can't fail to recognise.

So, we've come to the factory in the heart of Dublin

that's been making it since 1759.

That's massive!

I'm Gregg Wallace - and tonight, I'll be using my senses...

That is like smelling ten pints of beer at the same time.

..making discoveries...

So, the yeast is eating the sugar

and producing alcohol?

Exactly.

..and exploring this huge site...

It's up here that you truly get an idea of the mammoth scale

of this production.

..to find out how brewing tradition meets cutting-edge technology

to produce the perfect pint.

HE LAUGHS

I'm quite excited!

I'm Cherry Healey...

..and I'm helping out at this year's hop harvest!

And learning how water is treated so it's fit for a fine stout.

It's like a huge sieve,

but the holes are teeny, teeny, teeny tiny.

And historian Ruth Goodman...

Oh, wow!

..is drinking in the fascinating origins of the Irish pub.

This little enclosed space -

it's not just like a respectable space,

but it's for secret drinking!

This factory makes 2 million litres of stout every single day.

And we're going to reveal just how they do it.

Welcome to Inside The Factory.

This is the St James's Gate Brewery in Dublin.

Founded over 200 years ago,

this historic factory stretches across 56 acres.

That's as big as 112 football pitches!

It's a city within a city.

Here, they produce draught beers to be sold in pubs and bars,

from lagers to Indian Pale Ale.

But there's no denying it's the "black stuff" they're famous for.

So, you've guessed it -

today, I'll be helping to produce 20,000 50-litre kegs

of their Stout, Guinness!

Like most beers, one of the key ingredients is malted barley.

The factory receives up to 110 30-tonne deliveries

a week at intake -

where I'm meeting Bulk Raw Materials Manager,

Richard Sturgess.

Richard, hello!

Oh, how are you doing, Gregg?

Pleased to meet you. Mate, this place is enormous!

This might be the biggest factory I've ever seen.

This is one of the biggest breweries in Europe.

And this is where we get all our malted barley and barley delivered.

HE LAUGHS

I'm quite excited!

That's great, PJ, thank you.

Now, Gregg, there's a sample of the malted barley.

Take it up there and have a smell of it.

You get the sweet smell of it? You do. Yeah.

It smells like a breakfast cereal.

What we have here is a load of malted barley,

that comes from Irish fields.

That barley then goes through the malting process.

To "malt" raw barley, it's steeped in germination tanks

to encourage it to grow.

As the grain sprouts, it starts to convert its proteins

and carbohydrates into sugar-rich starch.

So, it's sweeter. Sweeter.

And the sugar and starch is essential in our brewing process.

What happens to it now?

We put it in our silos here behind us.

So, with the simple spin of a handle...

..the production of our Irish stout begins.

That's great, PJ. Thanks very much.

And the 30 tonne-load of barley

is transported to one of 12 huge storage silos.

Now, I've got my malted barley,

but the raw material that makes up most of your pint down the pub

is actually water!

Cherry's heading straight to the source.

I've travelled 20 miles southwest of the factory

to County Wicklow...

..home to Ireland's largest man-made lake.

When it rains here, which I'm told is quite often,

it falls up there over the Wicklow mountains,

and then it runs down and collects here at

this beautiful Poulaphouca Reservoir -

which provides much of the water needed for the city of Dublin,

and also our stout brewery.

Poulaphouca Reservoir was created by the damming of

the River Liffey over 80 years ago.

It's huge, covering 5,000 acres

with 50 miles of shoreline.

This water looks good enough to drink -

but actually, it has to go through an immense process before

it's fit for human consumption - or stout-making.

Purification takes place at

the Ballymore Eustace Water Treatment Plant.

Every day, up to 316 million litres are fed along three

1.6-metre diameter pipes, to the inlet building...

..where I'm meeting engineer Eoin Walsh.

Hi, Eoin, lovely to meet you! Hi, Cherry. Nice to meet you.

I've just come from the stunning reservoir.

I would like to know how you make the water clean

and safe for us to drink.

First, it's screened to stop any plants or fish,

or larger objects coming through.

You definitely don't want any random swimmers in your

cup of tea, do you? No, no.

But it looks really clean - what would happen if I drank that?

There's discolour and suspended particles in it -

that could indicate micro-organisms and bacteria, parasites that could

make you very sick, so first, we need to treat the water.

All outdoor water sources can contain dangerous levels

of micro-organisms.

To begin the cleaning process, the Liffey water travels through

a complex network of pipes to one of 20 sedimentation tanks,

each one holding 1.45 million litres of water.

This is like the biggest,

most beautiful water feature I've ever seen.

It's very calming, but it is making me need the loo.

This is the first real step in process here.

The sedimentation tanks take a lot of the colour and the particles out.

Sedimentation is the process of removing materials

like soil and algae, which contain harmful micro-organisms.

19 tonnes of aluminium sulphate -

a salt that acts as a coagulation agent -

is added to the water every day,

binding together the unwanted particles.

So, that's the water from the reservoir as it arrives here.

After the aluminium sulphate is added, you can see here that

the larger flakes are formed and fall to the bottom.

The sediment forms a sludge,

which is dried out and used as a filler in the cement industry.

After two hours in the sedimentation tanks,

the next stage of the big clean is the filtration station.

Eoin, water, water everywhere!

Is any of this drinkable? I'm so thirsty now.

No, this water's not drinkable yet.

They filter it first, to remove any small micro-organisms

that are still not being removed. How do you filter it?

We have a big bed of sand.

So, this sand here, the water comes up through the top, slowly

moves its way down through the tiny spaces left by the sand.

I see. So it's like a huge sieve,

but the holes are teeny, teeny, teeny tiny?

Exactly, yeah.

There are 36 of these 2.5-metre-deep filtration tanks.

They remove particles containing micro-organisms as small as

2 micrometres in diameter -

that's around 30 times smaller than the width of a human hair.

The water then passes through a filter to remove any residual sand,

and on to the final stage of the process.

Oh, wow! Talk about saving the best till last.

It's a bit like a leisure centre.

It smells even a little bit like there's chlorine.

Yeah, we do add some chlorine to disinfect the water.

After the process of taking all the particles out,

there's nowhere for the micro-organisms to hide,

and the chlorine can find them and finally disinfect

and make the water safe.

The chlorine is well within safe drinking levels,

and is vital to kill off any remaining harmful bacteria.

We also add fluoride here, in the pipes down below.

The fluoride's to help against tooth decay, strengthen people's teeth.

Really? It's like an added service you provide.

It's an extra public health measure we do here, yeah.

Water does contain small amounts of natural fluoride -

but in Ireland, drinking water must be between 0.6

and 0.8 milligrams per litre,

to help prevent tooth decay.

It's taken six hours for the raw reservoir water to become

clear, clean drinking water.

And after some final tests, it's ready to be pumped to the

good people of Dublin and the surrounding area.

Plus, of course, to our stout factory!

Back in Dublin,

16 tonnes of my malted barley travels from the storage silos...

..to the brewhouse.

First, a stainless steel mill

grinds it down to a fine powder called "grist".

Then, it's pumped along with 72,000 litres of water into

one of two huge brewing vessels...

Wow.

..where I'm meeting Quality and Production Manager Eamonn Power.

Eamonn, hello. Gregg. Gregg, nice to meet you.

This is very, very impressive. Thank you.

Out there, it's all 200-years-old.

In here, it is like space age, right?

The brewhouse we're standing in now is about ten-years-old.

And it's still one of the most modern brewhouses in the world.

Explain to me, please, what the brewhouse does.

OK, so the first vessel we're standing beside,

it's called the mash conversion vessel.

That takes the milled malted barley and water.

And if you look inside now, you'll see it's being circulated -

or agitated, as we call it -

to ensure that everything is being adequately mixed

throughout the vessel.

What sort of volumes are we talking about here?

Each holds about 100,000 litres,

which equates to about 175,000 pints per brew.

Like a colossal iceberg,

most of this 100,000-litre vessel is hidden from view,

stretching four storeys below the floor we're standing on.

Inside the giant structure, the malted barley and water -

now called "mash" - is heated to around 60 degrees Celsius.

And tell me why you're heating them up?

To convert the starch within the malt to sugars.

And it's THAT sugar that we then ferment into alcohol.

Inside the conversion vessel,

the milled malted barley contains enzymes and grains of starch.

The combination of water and heat causes the starch to swell,

then rupture...

..releasing long chains of sugar molecules.

The enzymes then attach to the long sugar chains,

breaking them down into shorter chains,

which ferment more easily into alcohol.

How long is it going to take? About two hours.

Our next stage is to separate the grain from the liquid -

and that happens over here in our separation vessel

called the "lauter tun".

97,000 litres of mash is pumped into one of these 14-metre-diameter

stainless steel beauties.

That's massive!

You've got big arms in there that aren't just stirring, are they?

They're dragging through the mix. What's that?

The purpose of that is to allow the liquid within the grains

to actually flow down through it. So, where is the liquid?

So, the liquid is actually beneath our feet at the base of this vessel.

If you follow me over here, I'll be able to show you

a little bit more simply what's going on in this vessel.

So, in this jar, we have a liquid that resembles what's in

our mash conversion vessel.

What's happening behind us is like a giant sieve.

On a much bigger scale, obviously.

But what we want to do is be left with a liquid that we call "wort".

I've heard that term before.

How would you describe wort?

So, wort is a really sweet-smelling, sugary liquid.

So, at this stage, we've converted the starch in the grains to sugars.

And we want to extract as many of those as possible into the liquid.

And the liquid is then called "wort"? Correct.

The leftover grains are used for animal feed,

while the all-important wort is continuously filtered

until it becomes a clear liquid.

This is what it looks like, actually, when it's all collected.

Have you taken that to the doctor?

If you want to smell it, you'll see that it's not what you think it is.

Oh! It's like a really strong herbal tea.

In a way, yeah.

So, that's your really sugary, sweet-smelling liquid.

Wow! That is really syrupy.

That's delicious! That'll cure what ails you.

No alcohol in there yet?

Correct, so fermentation hasn't started.

So, no alcohol yet.

It's sweet, but it is nothing like a pint, is it?

Not yet.

After filtering for around two hours,

97,000 litres of our clear, sweet wort

travels from the lauter tun vessel into another huge cauldron

called a kettle.

Inside, it's boiled for two hours,

killing any bacteria and evaporating around 6% of the water

to concentrate the sugary liquid.

But there's another key ingredient that many of us associate

with the beer-making process.

So, into the kettle, we'll add hops.

I have some examples here.

This is the hops in their natural form.

They will get concentrated either into liquid form or pellet form.

May I? Of course.

Wow, that is really strong.

That is like smelling ten pints of beer at the same time.

It is, isn't it? That's the smell of a beer.

Yeah. There's a very, very strong flavour contribution

from the hops.

This, I'm guessing, is the process to make any beer.

Am I right?

Very close, yes.

Around 20kg of the concentrated extract is added into the kettle.

And it's boiled for two hours,

until the distinctive hop flavour

infuses into the wort.

Hops are essential for giving us

that bitter taste that we've come to expect with beer and stout.

And Cherry's been helping with the annual harvest.

Britain's blessed with not one,

but two regions perfect for growing hops -

the south-east of England,

and here, in the West Midlands...

..where clay and sandstone store more moisture than

other types of soil -

perfect for the thirsty hop plants.

And I've come to a farm that grows enough of them to make

46 million pints of beer a year.

And it's not at all what I was expecting.

The 200-acre Stocks Farm in Worcestershire

is in the throes of this year's pick.

Alongside her husband, it's farmed by Ali Capper,

who's also a Director of the British Hop Association.

Hi, Ali, lovely to meet you. Hi, lovely to meet you, Cherry.

What an extraordinary place! I've never seen anything like it.

It's like a jungle and a vineyard.

Welcome to our hop yard.

So, are these vines?

They are bines, with a B.

These bines - with a B - grow up trellises in the hop yard.

While vines use tendrils and runners to grow up a structure,

bines use stiff hairs to wrap around their supports.

They are about 18-foot tall.

So, all the crop is at the top where the sunlight is.

Yeah. This is the hop.

Wow. It's the flower of the plant.

It's this that the brewer wants.

So, that's a hop? And the magic is inside.

If you open it up, see that lovely yellow?

Looks like pollen.

So, there are about 400 hop oils in there...

Wow! ..in the lupulin gland.

It's a bit like a tiny little sack that contains the hop oils. OK.

There are more than 250 varieties of hop grown across the world,

producing a cornucopia of flavours to suit all types of beer.

Today, they're harvesting a variety called Target.

It's full of oils that produce a rich, slightly bitter flavour -

perfect for stout.

So, you can feel it... Yeah, it's really oily.

..and you can smell it.

It's absolutely delicious.

It would take around 130kg of these oily hop cones to produce

the amount of oil needed for a batch of stout at the factory.

And the man tasked with harvesting this ten-acre field

is farm hand Sam.

Sam, I'm coming up!

Well, this is cosy!

As the tractor pulls us along,

Sam cuts down the bines with a simple hook.

So, you need to cut them with quite a lot of force?

Yeah, you're right.

It's action stations, as there's a short window

to pick the ripe hops -

usually from the end of August to early October.

Do you want to try? Yeah - ready, go!

Got it!

We carefully hold the blade to cut through the 1cm-thick

string holding the bines in place.

They kind of ping off, don't they?

And they go everywhere - OK, this is a big one.

At the peak of the harvest, they cut 3 acres a day,

producing 3 tonnes of dried hops.

As soon as the trailer is full,

it heads across the farm to the processing area.

It smells so intensely green in here.

By the end of the day in here, you can literally taste

the beer in the back of your throat.

Everyone seems in a real hurry.

Well, we are feeding a factory.

We're trying to get 19 bines a minute through the machine.

So, speed is really, really important? Yes.

With time at a premium,

this picking machine is designed to make the job easier -

at least, that's the idea.

The bines are tied by hand onto hooks hanging from

a fast-moving conveyor belt...

Oh, I see! Right.

..which is easier said than done.

I can't - my brain's gone weird.

That way? And then, that one.

OK. She's got it!

Oh, my goodness.

It's a bit of an arm workout, isn't it?

I think you've finished. Well done! I think we fin...

Hang on, what the...? What?! No, I quit!

I quit!

THEY LAUGH

After they're tied on, the bines are carried along a conveyor

to the picking machine's plucker bank.

A series of metal fingers gently remove the hop flowers...

..which are then spread onto huge metal trays,

and sent inside a kiln -

just 20 minutes after they were harvested.

Hoo-hoo! So, it's really hot in here!

It is like a sauna! Ooh, what temperature is it?

It's about 60 degrees C.

And we're trying to dry the hops as fast as possible,

but also as gently as possible.

Damp hops are at risk of rotting,

so drying them evaporates excess water while leaving behind

the crops' precious oil.

It takes seven hours in the kiln to reduce the moisture content

from 80 to 10%.

What's going on at the moment?

So, when the hops come out of the kiln and they're dried,

they then need to be conditioned, and we tip them...

Woohoo! ..into these large hoppers,

and here, they condition for 24 to 36 hours.

And that enables the hop cone

and the leaf of the hop cone

to regain some moisture.

Because we want to ensure that what the brewer buys

is a cone, not dust.

Oh, I see. And if they haven't been conditioned,

they just go to dust.

Retaining the moisture means the valuable oils aren't lost.

So, with the hops in tiptop condition,

they're packed into 60kg bales

and travel to processing centres for the oil to be extracted,

ready to be delivered to breweries,

where the small-but-mighty hops will deliver a flavourful kick.

Across the Irish Sea, in Dublin,

20kg of liquid hop extract has been boiling with our wort

made from malted barley, in the supersized "kettle".

So far, the brewing process has been much the same as making any beer.

But all that's about to change...

..at the roasthouse.

Inside this 120-year-old building,

they're preparing an ingredient vital to transform

our brew into rich, dark stout - roasted barley.

Whoa, it's getting warmer.

Richard!

How you doing, Gregg? Good to see you again.

Great smell!

Oh, this is the place where all the magic happens.

We're roasting the barley.

3,500 tonnes of barley is fed into a hopper above the ovens.

It then drops into a rotating steel drum,

where it's roasted at 232 degrees Celsius.

Are you roasting the malted barley?

No, we're roasting pure barley.

This is raw barley from the fields.

You pick up a handful of that and smell it.

It's a pure grass smell.

Very clean, crisp, grass smell.

That's what we use for roasting.

What is it that the roasting of the barley gives you?

It gives us the colour and also the flavour -

that roasted flavour is what we're looking for.

So, the roasting the barley is what makes the difference

between a pint of beer and a pint of Irish stout?

It's the roasting?

No doubt about it, Gregg.

Hundreds of tonnes of barley are roasted every week.

The intense heat inside the rotating ovens causes sugars

and amino acids within the barley to undergo chemical reactions,

causing the grain to brown and flavour.

These browning processes are known as the Maillard reaction.

After two-and-a-half hours of roasting,

the barley is ready.

We have a sample here in the drum.

Just pour it into there, Gregg.

You smell that roasted?

That is the smell of ground coffee.

That's a ground coffee, there's a bitterness to that.

It's almost like the bitter, almost-burnt bit you get at

the end of a joint of meat that you can't resist.

It's a good description, Gregg.

Before my roasted barley can move to the next stage,

it must pass an important test.

Using a dinky hand cutter,

Richard checks that the barley has the desired black colour.

Each grain is cut in half.

And you can see the samples of grain are darker on the outside,

and a little lighter on the inside.

As a result, we can see that this roast is completed

and ready to go.

If that wasn't roasted all the way through,

we might not have stout - we might have a very pale ale.

We wouldn't complete the roast.

We'd leave the roast on for another two or three minutes,

because the roast really happens in the last few minutes.

We need one of these for joints of beef.

You need to be able to cut through the middle and see that

it's cooked all the way through.

We'll adapt it, make a fortune. You would do, yeah!

If you do it, I'll go shares with you.

So, no roasted barley, no black stout.

I couldn't have said it better meself, Gregg.

The roasted barley's got Richard's seal of approval -

so 370 litres of cold water is pumped into the drums,

bringing the temperature down to 110 degrees,

stopping it from cooking.

Then it's driven a mile across the huge site to the brewhouse

to be turned into wort, just like my malted barley.

So, I'm going back to the brewhouse now?

Yes, Gregg, that's where you're heading now.

My step count is going to be through the roof.

Good for you, Gregg!

HE LAUGHS

Cheers! God bless you.

Fascinating place, but it's massive!

The roasted barley may be getting a lift,

but I've got to find my way on foot.

The factory's grown over the years,

so there's a public road running right through the middle of it.

But that doesn't bother me - oh, no -

there's a handy 112-metre-long tunnel

linking one side to the other.

How many factories have a tunnel in the middle of them?

It was constructed in 1895 by James Henry Greathead -

the architect responsible for some of London's Tube stations.

Having resurfaced back at the brewhouse,

I head down four flights of stairs and finally get a chance to see

the massive brewing vessels from below.

Inside, there's a batch of roasted barley wort,

made using the same method as my malted barley.

Eh, Eamonn!

Mate, it is tropical-hot down here, innit?

One of the warmer parts of Ireland.

So, what we've got there is another wort, but a black wort.

Correct, and it's very, very hot.

It's round about 80-90 degrees at the moment.

That's got a smell like caramel.

Almost a burnt sugar.

You do get that caramel note in certain cases,

I've got a cooled-down sample from earlier.

You can taste it, if you like, but it is obviously a very,

very strong-tasting liquid.

Is it going to be sweet like the other wort? Not as sweet.

That's got a real bitter finish, but that is toasty.

Yeah. It almost tastes like the smell of a wood barbecue.

What's in your hand now is effectively the special ingredient

that converts our pale wort into stout.

Without this little thing here,

we've got a pint of ale.

With this, we've got a pint of stout. Correct.

The roasted barley wort is sent to the huge kettle

holding the malted barley wort I saw earlier.

It's blended at a ratio of one part roasted barley wort to

nine parts malted barley wort.

So, this is where we combine our roasted barley-wort

with our pale wort.

I took a sample earlier.

That's looking like a glass of stout without the head.

Ooh, that, I like. It's getting there. Ohh!

That starts off treacly-sweet.

But it finishes with that Irish stout bitterness.

So you should be able to see everything starting to come

together in this one.

Nice to meet you, Gregg. You're a fine man.

Ireland's known around the world for its pubs!

But when did this tradition start?

Ruth's pulling up a bar stool to find out.

RUTH: Ireland is home to more than 6,000 pubs.

And over 750 of them are in the busy capital of Dublin.

So what better place to start my crawl through their history?

And to help me, I've enlisted pub historian Eamonn Casey.

Throughout the centuries in Ireland,

there were always a hodgepodge of unregulated taverns,

coaching inns, ale houses,

many of which sold questionable brews.

SHE LAUGHS

But from 1635, these early public houses had to obtain a licence -

and there were some very strange and surprising ways to get one.

Why are we meeting here on the edge of Dublin?

That pub you see over there commenced life as a family home

with absolutely nothing to do with the licence trade.

The house received its licence to sell alcohol at a time

of national tragedy.

In the 1840s, the Irish potato crop failed,

and it's estimated that the subsequent famines resulted in

the death of more than a million people -

commemorated by this memorial.

In 1847, as the bodies piled up,

John and Catherine Howe developed a community morgue.

And, as a consequence of that, they also received a licence.

So, that people can have a wake, presumably?

Yes. Its history totally evolved from of a community morgue

to a prosperous licensed premises.

So, it's a home, a morgue, and a pub

as a result of this tragic episode in history? Absolutely.

By 1870, 800 premises which had become morgues

also obtained licences to act as pubs

at the heart of their communities.

Shall we go and look at some other pubs? Yes.

SHE LAUGHS

Whilst the number of licensed pubs was growing,

Victorian Dublin was still the centre of religious

and moral values...

..which frowned upon the consumption of alcohol.

Oh, wow!

So, where have you brought me, then?

We're outside the Palace Bar,

one of the iconic Victorian pubs of Dublin -

and one of my own favourites.

The battle for more licensed premises took place at a time

when both church and state were supporting a Temperance movement -

to stop drinking.

This campaign in Ireland, the Irish Temperance Campaign,

was to convert souls to sobriety.

To a life of total abstinence.

Yes, but people found ways to have a little tipple,

and drinking continued in the pubs,

and also in the grocery shops.

The grocers' shops? Yes.

Flying in the face of Temperance,

enterprising grocers saw an opportunity

to increase their business.

They were only supposed to sell alcohol to customers to take home,

but quickly found a way round the licensing laws.

What they were doing was actually erecting screens within

their premises and allowing the public to drink alcohol illegally

behind that screen.

I can see the publicans wouldn't have liked that.

I mean, if you were running a pub, and then the bloke down the road

selling the groceries is suddenly in competition... Absolutely.

Well, there was a bitter feud between the licensed publicans

and the grocers, which lasted for 25 years.

By the 1860s, the Temperance campaign had lost momentum.

And in 1862, the publicans and grocers put aside their differences

to form a trade association.

At that time, pubs like the Palace Bar could commence

to sell groceries.

And the grocers were able to adapt their premises

to become licensed premises.

That is a really creative way of solving an argument, isn't it?

So, if you're going to nick my business, I'm going to nick

your business. We'll both share both businesses.

So, as well as morgues, grocery shops became pubs, too.

And the 1870s saw a boom in the number of licensed premises.

And with it, a whole new clientele was born.

It became respectable for women to visit and sit in a snug like this...

Cosy, isn't it?

..while collecting their shopping.

The first purpose of the Victorian snug in Dublin was for

the Victorian ladies who came in here in order to buy tea.

Back in the 1880s, tea was a far more desirable

and expensive item than coffee.

Oh, we mean loose tea? Loose tea, yes.

This new brand of pub customer - the middle-class housewife -

found there was another advantage to doing their shopping in a pub.

She would just press that bell.

The publican would appear, and she might say,

"Could I have a half-pound of your beautiful tea, please"?

And he would say, "Would you like a little beverage

"while you're waiting"? Oh, no, I couldn't possibly!

But on second asking, she would consent and say,

"Oh, maybe a gin". "Oh, well!"

So, you've got this little enclosed space -

it's not just a respectable space, but it's for secret drinking!

FIDDLES PLAY Ooh, hang on, listen, listen!

That's music! Shall we go and have a listen?

By the turn of the 20th century,

Dublin was home to more than 1,500 pubs.

And nowadays, you can find so-called Irish bars around the world -

trying to emulate the warmth and welcome of a place like this.

But you can't beat the real thing.

The Irish pub - we have to think of it as a grocers,

it's a place for music,

it's a place for the community.

And yet, despite everything,

this is the place you come for the craic.

MUSIC ENDS

GREGG: Back at the factory,

we're nine hours and 50 minutes into production.

My dark, bittersweet liquid - or wort -

is packing an increasingly rich flavour.

But it's not stout yet.

For that, we need yeast.

So, I'm heading to the microbiology lab...

..where I'm meeting group microbiologist Dan Kerruish.

Hey!

Dan, I've got these, as well.

Come on, high five.

All right. I didn't expect the next stage to be a lab.

Not only a lab, but a library.

Let me show you.

In here...

..we have hundreds and hundreds of yeast.

What? And we use these yeast...

..to make beer.

The yeast we're using today dates back from 1903.

Wow! That's incredible.

Yeast is a single-celled living micro-organism

from the fungus family.

There are around 1,500 species,

and some are better than others for creating stout.

This one, dating back to 1903, is unique in that it ferments

quickly without imparting its own "yeasty" flavour.

Is that liquid nitrogen? Liquid nitrogen.

Why do you store them in that?

So, we keep it at -196 degrees Celsius,

because we know that the yeast will keep. Right, OK.

Stick that back, cos that's scaring me a little bit.

We normally only get that in a MasterChef final.

At -196 degrees Celsius,

the yeast can be stored indefinitely and used to create

"daughter" cells that are young and active.

Bit like me.

Could you explain to me, please, the job that the yeast

is doing inside the stout?

So, the yeast is there. It's producing the alcohol.

It's producing carbon dioxide, as well,

and it's also producing some of the flavours.

How is it doing that?

It does that by feeding on the sugar.

So, it takes that sweet wort, and it converts it to alcohol

and carbon dioxide.

So, the yeast is eating the sugar

and producing alcohol?

Exactly. Clever little thing.

So, what do you do?

You just tip that into a vat of wort, do you?

Oh, no, no, no.

We take the sample of yeast, and then, we grow it up

into different stages.

So, we put it into this conical flask,

which has sweet wort in it.

We leave it for 24 hours, and it starts to grow.

We then transfer it to a larger flask.

So, we've gone from a million cells here to roughly

50-60 million there.

And then, we put it into what we call a Carlsberg flask.

We need roughly between 10-15 million cells per mil.

This thing's extraordinary! It is indeed.

It takes about a week for the yeast to grow enough to be

ready for my sweet wort.

This is one we prepared for you to take down to the brewery.

Not far away? Not too far.

Mate, everything around here is far away.

Thank you, Dan. You are a clever man.

DAN LAUGHS

I'll look after your yeast.

The factory gets through one Carlsberg flask every three weeks.

And this one will eventually help to ferment

28 million litres of stout.

So, if I drop it, that's 50 million pints down the drain.

Thankfully, I've got it safely to the fermentation plant -

and Brewing Production Manager Neale Young.

Neale? Ah! Gregg.

Delivery of yeast for you, my friend. Great stuff.

Thanks very much. Very precious, this.

My yeast is added to yet more wort

held inside a 9,000-litre tank called a propagator vessel,

where it multiplies even further.

Then the 9,000 litres is pumped into one of the factory's

290,000-litre fermentation tanks...

..which is full to the brim with sugary wort.

The factory has 52 of these colossal 28-metre-high containers

spread across the site -

all dedicated to transforming wort into stout!

Are we going up there? All the way to the top, yeah.

Ooh-ho-ho!

Lucky I'm OK with heights!

Whoa! Right, Gregg, here we are.

Whoa-ho-ho!

It's up here that you truly get an idea of the mammoth

scale of this production. Yeah, absolutely.

As impressive as they look, they're doing a job, right?

What's happening in here? These fermenters, right,

they're taking the wort over from the brewhouse, OK?

And that wort's...it's laden with sugar. And, once the yeast goes

inside, it's going to start the important job

of creating the alcohol.

Inside the tanks, my sugary wort finally becomes stout.

But it's not a quick process.

Over the course of two-and-a-half days,

the yeast feasts upon the sugars,

expelling alcohol and carbon dioxide.

The yeast is removed and re-used to help ferment other vessels...

..while the carbon dioxide rises

and is captured at the top to be extracted.

All the carbon dioxide that comes off the fermentation,

we recover that, and we use it within the plant itself.

We also collect it and purify it, and we use it in our packaging

plants and in the keg plant to carbonate some of the beers.

So, it's fully utilised.

So, inside one of these, you've got how many pints?

There's enough stout in here to make 950,000 pints.

And how many of these have we got up here? 52.

I can't fathom it. It's an incredible scale.

Well, we normally have about 35 million pints at

any one point in time.

As stunning as the view of Dublin is,

I want to know what the fermentation process has done to my stout.

So, we're heading down 28 metres,

to the base of the colossal containers.

Gregg, this is one of our fermentation tanks.

It's actually the one that we were on top of just earlier on.

So, if you like, I'll pour you a sample.

Yeah, can I? Yeah, go on!

Taking longer than a pint takes in the pub, Neale.

Well, you've got to wait for it, Gregg.

Now, before you try this, Gregg, I've got to warn you,

it's 7.2% alcohol.

That's nearly double the strength of the beer

that I would drink at home.

Absolutely, it's very strong.

Whoa, that is strong, innit?

That is seriously strong!

It's got the nice kind of toasty flavour,

and it finishes with a lovely bitter finish,

but that is seriously strong.

That's a little bit like someone's put a whiskey in my stout.

It is, yeah. Why do you make it so strong?

Well, you see, we've got to make different stout products

for different countries.

So, you start with the strongest, and then, you...

Start off strong and then we can adjust it down depending on

what we want to do with it.

Neale, thanks for that. Thanks, Gregg.

I can't have too much of that. I really can't.

After two-and-a-half days fermenting, the stout is transferred

to a maturation vessel where it spends another two days

and seven hours to allow the flavour of the stout to mature.

Once you've got your pint,

the perfect accompaniment is often a good pub game.

Ruth's been investigating their surprising role

during the Second World War.

RUTH: From darts...

..to board games, and even playing cards,

we seem to love getting competitive alongside our favourite tipple.

But apparently, there was also a secret role that these played

during the Second World War.

In search of facts, I've arranged to meet a contact -

historian Dr Helen Fry,

an expert in the history of spy craft.

Helen, hello!

Hi, how lovely to see you!

I want to know what espionage and pub games have got

to do with each other.

Well, there was a top-secret section of military intelligence

that was doing all kinds of interesting things with pub games,

and it was as top-secret as MI5 and MI6.

This was a branch of military intelligence called MI9.

During the Second World War, more than 170,000 British service

people were captured and kept as prisoners by German

and Italian forces.

Under the leadership of Brigadier Norman Crockett,

it was MI9's job to help them escape.

And there was one group of highly skilled people on whom their efforts

were particularly focused.

SHE LAUGHS Now, that's a plane-and-a-half.

What sort is it? Oh, it's a Mosquito bomber.

So this would have been used by Bomber Command in missions

over Nazi Germany and other enemy-occupied territories.

Pilots were in high demand, so it was vital that any shot

down and captured were returned to the skies as quickly as possible.

The problem was how to get help to those who were caught.

How did Crockett come up with the plan?

Well, he enlisted a former pilot, Christopher Clayton Hutton.

He was interested in illusionism, in escapology.

During the war, Christopher Clayton Hutton worked mostly

as an intelligence officer for MI9,

but his interest in magic tricks inspired him to devise

an ingenious plan

involving pub games, of all things.

Ah, well, you couldn't get a much more traditional pub game

than a dartboard, could you? No, exactly.

Well, this is a modern version,

but, of course, what we've done

to show you is that this comes out here and between there, this comes

apart and there's a hidden compartment.

So this would have been, as in the picture here,

Clayton Hutton's original design.

Equipment to aid escape, like hacksaws, screwdrivers

and compasses could easily be hidden inside the dartboard.

But the most amazing trick of all was pulled off with a humble

deck of cards.

Surely, nothing can be hidden in a pack of cards?

Well, you'd be surprised.

These are incredibly rare,

actually, there aren't many of these that survive.

If you slice this open,

look, you've got part of a map.

This is Westphalia,

part of what was then Nazi Germany.

Chessboards were also adapted, hiding everything from magnifying

glasses to silk maps.

How did MI9 manage to get this sort of equipment to people

who were stuck in prisoner-of-war camps?

Well, the Geneva Convention allowed for parcels to be sent to

prisoners-of-war by their families,

and MI9 came up with fictitious charities, and they would send

this into prisoner-of-war camps.

What we've got here is a letter from 1941

from the Licensed Victuallers

Sports Association... So this is completely fictitious... Yes.

..there was no Licensed Victuallers Sports Association?

No, this doesn't exist. OK.

And it says, "Owing to the difficulties in the present

"situation of obtaining new supplies of sporting goods using our various

"public houses and inns, your name has been published as a

"prisoner-of- war, and our committee

"feel that no better purpose can be found

"for the use of our present stock of goods than to distribute them

"to those unfortunate members of the services who are at present

"in prisoner-of-war camps."

And here it says, I really like this, "Parcel number 14361,

"containing five records, one dartboard, one chess set, one

"shove ha'penny board."

So the Germans would see this and think

it was just a charitable act, sending surplus pub games

to blokes in prison?

Under this cunning guise, pub games were sent across enemy lines

into Germany and Italy, giving their recipients

a very pleasant surprise.

I've got an example for you of a naval prisoner,

Sub Lt John Pryor.

And look what he's written, "A parcel

"from the Licensed Victuallers Association."

But look what it says, it actually says what's inside.

Can you see what...?

"When we opened it, it contained a chessboard..." Yes.

"..and a beautiful set of chessmen in a polished wooden box.

"When we split open the chessboard, it contained

"Reichsmark, hacksaw blades." Yeah.

SHE LAUGHS

So here we have proof that somebody has received one

of these from the made-up Licensed Victuallers... Yes.

..and has found it useful.

Lt John Pryor, along with 35,000 other prisoners-of-war,

used these cleverly concealed tools to plan their escape.

And the pilots who found their way back home bravely took

to the skies again,

helping to secure victory.

GREGG: Back at the factory,

I'm uncovering some secrets of my own.

My stout's been fermented with yeast, giving it an alcohol

content of 7.2%.

From the maturation vessel,

it's pumped through a series of pipes where it's pasteurised

by blasting it with steam to prolong shelf life,

before finally reaching the kegging plant.

Here, it's blended with water, bringing down the alcohol content

to a more palatable 4.2% for the Irish market.

Guiding me through this muddling maze of pipes is packing

manager, Patricia Gormley.

So here, Gregg, we are the first step of the process here

in the keg plant.

What happens to it here? I thought you just put it in barrels.

Yeah. Here's where we add the nitrogen to the stout.

Nitrogen? Yeah.

Nitrogen's all around us.

It makes up 78% of the world's atmosphere.

So we're breathing nitrogen anyway? We're breathing nitrogen anyway.

Right, right, two things I need to know.

The first one is, why are you putting nitrogen into the stout?

Nitrogen gives the stout that smooth, creamy head height.

So it's the small bubbles that are naturally forming

in the nitrogen.

They give it a subtle fizz that makes the beer a creamy

and a heavy taste.

So the bubbles aren't big enough to make it like bubbly

like a lager? No.

The nitrogen gives it that creamy, distinguishable head.

Compared to carbon dioxide,

nitrogen has a much smaller molecular size, so the bubbles

it forms are packed closer together.

So how are you putting it in?

We're actually injecting it in at 9 bar pressure.

That's a lot of pressure.

That's four times the pressure that's in your car tyre.

The pressurised nitrogen gas is fed directly into the stout,

where it dissolves into the liquid.

So, all right, let me say

I put nitrogen at pressure into a coffee,

would it make the coffee thick and creamy?

Yeah, it would, yeah.

And without that, what would it be?

Just...? You'd have a flat head.

Excuse me? You'd have a flat...

Oh, not me... No, not you.

My nitrogen-rich stout is finally ready to be put into kegs.

MACHINES HISS AND CLANK

It's loud, innit? It's very loud, yeah.

Crashing heavy metal!

It's no wonder it's noisy.

An average of 15,000 metal kegs come through here every day!

I don't know why,

I just thought they might still be, like, wooden barrels.

Oh, the last wooden barrels were used in the 1960s.

HE CHUCKLES

Right.

Metal kegs are more durable and easier to sterilise,

and that's important because they're part of a continuous cycle.

Each week, more than 100,000 kegs are collected from pubs

across Ireland and the world, and brought back here where

they're washed, ready to be filled with stout all over again.

This is a big old operation.

Yeah, it is.

So you'll see that the kegs are being fed on into the filler, one

by one, and as they turn around the carousel,

they're slowly being filled.

Grippers grab the kegs 25 at a time.

The stout is pumped inside and held under pressure of 4 bar

to maintain the level of nitrogen in the liquid.

How long does it take you to fill a keg?

We can fill a keg in about 30 seconds.

And what volume of liquid's in there? 50L.

How many pints is that?

88 pints. 88 pints? 88 pints.

We have the capacity a day to do 48,000 50L kegs.

So that's 2.4 million pints a day, which is about

25 million pints a week.

It's a lot of pints. It's staggering!

It's staggering volumes.

I find this stuff sort of quite hypnotic.

You know the steel balls on the streets? Yeah.

This is like watching one of them.

The full barrels exit the filler and travel along computer-controlled

conveyors where a shrinker melts caps onto the tops to keep

the connectors clean.

Then they're transported 30 kegs at a time to the dispatch yard...

..where I'm meeting logistics manager, Ciara McGowan.

Ciara, hello. Hi there, Gregg.

Good to meet you. Nice to meet you, Gregg.

From this depot, do you distribute all over the world?

Yes. This area you're in here,

this is for distribution within Ireland only.

So in Ireland itself,

how many trucks are you sending out every day?

From this site, we're sending out 40 vehicles on average every day.

So how many kegs of stout are going out of here every day?

On average, about 6,500 kegs of stout.

How many pints is that, do you know? Over half a million pints, Gregg.

These two trucks you just loaded, where are they going?

They're going to make deliveries in Dublin City Centre.

So not far? Not far at all.

Would you like to get in one? Could I?

Yes, absolutely. What, make a delivery?

Let's get you safely onboard.

Hello, sir.

This is Pat.

Wahey, come on!

Cheerio.

Seven days and five hours after the start of production,

we're delivering Irish stout to a pub in the heart of Dublin.

The equivalent of 7,500,000 pints

are delivered every week throughout Ireland and the UK,

and they're supped as far afield as South Africa, the USA and Japan.

It's amazing to think that something that looks so simple has gone

through so many processes before it's pulled into a pint

for us to enjoy.

From space-age brewing

and sci-fi yeast,

to phenomenal fermentation,

and a cacophony of kegs.

One final test.

Cheers!

The factory has come a long way since its first

early assembly lines.

But how did we get from there to where we are today?

Explore the history and future of the factory

in an interactive timeline.

Go to...

..and follow links to The Open University.