With free beer courtesy of BrewDog, it was perhaps not surprising that the Give in to Fermentation event was a sell-out at the recent Edinburgh Science Festival.

Add in the generous platefuls of bread, salami, pickles and sauerkraut, and the speakers were almost an added extra.

My favourite was Graeme Walker, a Professor of Zymology from planet zog - well, actually Abertay University, while the 'z' word involves the study of yeast. His passion for the stuff was infectious, and he clearly relished the chance to swap his laboratory for a stage at the Summerhall arts venue to tell us all about it.

"What has yeast ever done for us?" he cried before extolling the virtues of this "very sophisticated unicellular fungi". He then recited its achievements under the letter B: "It's given us brilliant Nobel prize winners, bread, beer and all alcoholic beverages, biofuels, biopharmaceuticals and billions of pounds! Is there another organism in the world that makes more money?" To which someone shouted: "Simon Cowell"

That may be true, but there's no contest when it comes to sophistication and generosity of spirit. We are surrounded by billions of yeast cells in the air, on our skin and in our gut, and the selfless dedication of the ones involved in fermentation is truly remarkable. They feast on fermentable sugars converting them to ethanol and CO2, until eventually the alcoholic strength kills them.

Even in death yeast cells add flavour to bottle-conditioned beers and all those wines kept on their lees like Champagne. The professor explained that their mission in life was to reproduce and that ethanol was a byproduct. However, given that their sugar-fest invariably leads to suicide, maybe they are not quite as smart as he claims.

Another byproduct, this time from Ireland's dairy industry, is Bailey's Irish Cream, which is basically fermented cheese whey - not a description you'll find on the back label. Yet for all the ingenuity of the drinks industry, a modern zymologist is more interested in alcohol as fuel. Alcohol typically accounts for 5% of unleaded petrol and was apparently meant to power the original Model T Ford.

Next weekend, with the scientists safely back in their labs, Summerhall will host its annual beer festival with cider and home grown Pickering's gin on the side (tickets at: www.summerhall.co.uk). Meanwhile Glasgow's Drygate Brewery is gearing up for its giant Craft Beer Rising event in September.