OnTap Magazine

here was a time when brewers didn’t know that yeast was important in making beer. In fact, there was a time when nobody, including brewers, even knew that yeast existed. At all. In times of yore, before clever folks discovered what would later become modern microbiology, brewers had all sorts of weird and wonderful explanations as to how malty tea became beer. Some believed in the magic stick, which they used to stir the brew (which was of course was coated in invisible yeast particles), while others were convinced that fermentation was due to divine intervention. But now that we’re all modernised and wash behind our ears and stuff, we know that yeast, and especially the Saccharomyces cerevisiae and Saccharomyces pastorianus species, is responsible for doing the heavy lifting in fermentation. It’s yeast, which is a fungus, that converts the sugars in wort into ethanol and CO2 (and more besides). And these by-products are kinda important in creating the suds that we love. That’s why I find it a bit surprising when I encounter homebrewers who still act as if that whole science and microbiology thing never happened. Teaching homebrewing classes, I’ve discovered that the yeast pitching part is often seen as an also-ran phase of a course. Students are like, “Just add that packet to the wort? Cool. Check that box.” Perhaps it is because the other parts of brewing are just so much more exciting. I mean we’re steeping and recirculating and boiling up a storm in the hot side of brewing while in the cold, fermentation cycle, it’s mostly just waiting and praying that the beer turns out okay. But don’t let this seeming passivity fool you. What happens to wort once yeast is introduced is just about one of the most important parts of brewing good beer. It is often said by experienced beer-makers that brewers don’t make the beer - the yeast does. And they’re not wrong. In fact, many beers (especially those lovely Belgians) are ridiculously simple from a grain and hop-bill perspective. Yet, they have amazingly complex flavour profiles. Consider the Belgian Tripel. The beer usually has, at most, two malts and some very subtle hop additions. Add to that a whole bunch of sugar (take that Reinheitsgebot !) and that’s it. Yet, Tripels have complex flavours that range from banana to white pepper and more. The star of the show? You guessed it: yeast. T Brewers don’t make the beer - the yeast does. HOMEBRU ontapmag.co.za | Winter 2018 | 53