The unique taste, texture and colour of Guinness are the result not only of its four ingredients – barley, hops, yeast and water – but also of what is done to them and the way they are handled once they pass through the gates of the brewery. Tender loving care doesn’t come close to describing it.
One thing that sets Guinness apart from other brewers is the fact that it roasts its own barley. While it’s fairly well known that barley is an essential ingredient of most beers, less well known is the fact that it is effectively divided into two separate and distinct ingredients for Guinness: malted barley and roasted barley.
Malted barley is barley which is allowed to germinate to a certain point, explains Gearóid Cahill, Guinness master brewer at the St James’s Gate brewery.
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“We wet it and let it germinate under very controlled conditions. Then we halt the germination process and dry it and use it as it is needed. We dry it in a kiln, and it matters how quickly you dry it for its flavour and other characteristics.”
The quality of the barley is also vital. “Not every farmer can grow malting barley, and not every farmer wants to,” Cahill says. “Not only is it important for the flavour of the beer; it also produces the sugars and nutrients for the yeast. And if the yeast is not happy, you won’t get a good beer.”
This care for the wellbeing of the yeast extends to all of the ingredients and is shared by all the brewing staff.
"I've just come from a meeting where we were looking at the new supply of barley which has just come in," he says. "Each year's crop differs from the last. This time of year there is always great excitement about what the crop will be like – what it will feel like and taste like. We don't know what Mother Nature is going to present us with."
This is where the skill and collective knowledge built up over generations come in, particularly when it comes to the roasting barley.
“Roasted barley is an incredibly important building block of the flavour of Guinness,” Cahill says. “It has a very distinctive flavour and colour. There is a whole flavour symphony going on in our roasted barley. There are so many flavour components in it we haven’t measured them all. There are toffees, chocolate, coffee, toasted components, roasted components and many more.”
But it is not as simple as just taking part of the barley supply and putting it in a roaster.
“There is a natural variation in the crop each year, depending on the weather conditions and the region it is grown in and so on. Planting conditions, growing conditions, head formation, harvesting conditions all affect it. This year’s crop looks really good. But if there has been a drought or a cold spring the crop can present challenges, and we have to look at different workarounds to deal with them.”
Only barley with very specific characteristics is chosen for roasting. “One of the things that’s very important in roasting is that you need a consistent size of grain. We are roasting them to the point of flame. We look to have big bold grains of barley in there. Certain barleys are suitable for malting and certain barleys are more suitable for roasting.”
Guinness has three barley roasters, which are actually coffee roasters; each roasts 3.5 tonnes at a time, and they are among the biggest roasters in the world.The roasting process effectively begins the moment the grain arrives at the brewery. The roasting team examine the barley. They touch it, smell it, taste it and get a feel for the best way to roast it. What worked for last year’s crop will not necessarily work this year.
"They want to find out if it smells and tastes right, if it is friable," Cahill says. "We call it brewing with the five senses. You have to have everything right. We are constantly smelling and tasting, right the way through the process. The analytic process can only tell us so much. That's why the brewers are there 24 hours a day. It's a crossover between a science, a craft and an art. It's a combination of skill, technology and Mother Nature. It's very much the same as when Arthur Guinness was a young fella."
The roasting process remains almost completely under human control despite all the technological advances over the centuries.
“The roasting process is not 100 percent automatable,” Cahill says. “And the last 10 minutes are the most important. Some brewers may shy away from it, but we go all the way to where it is about to reach burning point – that’s 232 degrees Celsius. At that point it will all go up in flames if you don’t time it properly.
“The end part of it is determined by the human eye. During those last 10 minutes you see the roasters taking it out, splitting the grains, saying they will give it one more minute or another three minutes, or whatever. Human intuition is still the best way to do it; it’s the only way to do it.
“To get the barley roasted properly, so that it has the right flavour, texture, and colour, and takes steely nerves on the part of the roaster. If you think you know about roasting, go talk to the guys who actually do it, and then you’ll realise how little you know.“Nobody roasts barley on the scale we do,” he adds. “We prefer to do it ourselves because we know we will get it right.”
Cahill speaks with pride about the skill involved. “It is not brewing by PlayStation. It is about absorbing the knowledge built up over years and generations. The knowledge and craft is handed on from generation to generation. I am just a temporary custodian of the Guinness legacy, and I will pass on that knowledge to the next generation. I came here with a degree and a master’s in biotechnology, but I then had to do brewing exams in Guinness. I subsequently did a PhD in stout brewing. It’s the only place in the world where you could do that.
“We almost have our own university of knowledge here within these walls, and it’s going to stay within them. It is this knowledge which allows us to create great new products like Dublin Porter or West Indies Porter.”
Discover the stories and culture behind the Guinness brewery at St. James's Gate: www.pursuitofmore.com.