In part three of our entertaining and informative series about making beer we look at the most interesting, misunderstood and volatile of all the beer ingredients. No, not the pissed idiot in the pub. Yeast. Perhaps no other step of the brewing process is as simple, yet easy to stuff up than the pitching and working of the yeast. This is the step which involves working in harmony with a living organism - one which, treated nicely, will reward you with rivers of golden beery enjoyment and, if mistreated, will curse you with 23 litres of cats’ piss. Yeast
Yeast is, put simply, a single cell micro-creature of the fungus family. It has millions of different sub-groups and are to be found floating free and roaming wide and wild everywhere. Some are good at making bread and some are good at making people sick and some are good at making beer. Some of which makes people sick. But here is why you need to respect yeast.
Yeast is ancient, prehistoric. Maybe a caveman - let’s call him Grog -discovered the natural effect that this airborne miracle had in the right circumstances. Perhaps he left a bowl of half finished grain outside the cave one night. In the morning he awoke to find his porridge in a state of froth and the overnight rain had turned it into a drink of sorts. A taste told Grog that some kind of magic was afoot.
Some anthropologists even believe that mankind’s change from nomadic hunter-gatherer to community group can be attributed to the discovery of the effect that wild yeast had when it infected this source of grain in the right temperature range which then got rained on and magically produced a foamy beverage which, after a few bowls, made Mrs Grog start to look pretty good. For the staying put and planting of crops to make beer - and perhaps some obscure food products, like bread - is thought to be the turning point of civilisation.
Yeast has, since then, been a miracle and a menace to generations of brewers. In the right conditions - temperature, food source and protection from bacteria - it will begin it’s beer making by multiplying rapidly, then feeding on the fermentable sugars and, finally, producing alcohol and CO2 before dropping to the bottom to become a rich source of vitamin B - the very vitamin that beer consumes. Magic! It is also responsible for many of the flavour notes found in different beers.
So there it is. A little miracle. It happens, but nobody can really explain how. Like Jason Gillespie’s 201 not out or the apparent popularity of dickheads who go on Big Brother , yeast is sometimes difficult to figure out - but impossible to ignore.
Next Time - Water
Brewing world heads to Wellington
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