Whisky Magazine Issue 84
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The number of distilleries using brewer's yeast has declined significantly since the 1990s. Ian Wisniewski asks why.
Brewer's yeast used to enjoy a monopoly in malt whisky production,until distiller's yeast became more established in the early 20th Century, and using a combination of both types of yeast became standard practice.
Being recovered at the end of fermentation, brewer's yeast is termed a secondary strain, and has a different genetic profile to distiller's yeast, which is a primary strain (being cultured).
The method of harvesting brewer's yeast depends on the design of the fermenters. This could mean raking yeast from the top of the fermenter, then pressing the yeast into a cake.
Alternatively, fermenters with cone shaped bottoms provided an area in which the yeast could settle,and be drawn off for filtration, then pressed into a cake.
Sourcing brewer's yeast traditionally meant either dealing direct with large breweries,who employed dedicated sales staff, or more usually,merchants acting as middlemen between brewers and distillers.
“Yeast was originally delivered in barrels by train in liquid form,in warm weather the bung would almost be popping out. Then some breweries moved to centrifugal filtration and making a pressed yeast,”says Derek Sinclair of Inver House.
Dennis Watson of Chivas Brothers adds:“In the 1970s there were still some breweries shipping brewer's yeast in small pressurised tanks, which could go on the back of a lorry, and once unloaded at the distillery these tanks were linked up to pipe work from where the yeast could be sent to the washbacks.” M...