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Yeast: It can finally affect the flavor of whiskey "fairly"!

Barley, grapes, and grains can make mellow wines, flour can make fragrant bread and pastries, fruits and milk can also make attractive jams and cheeses, and even tea leaves can become fragrant and refreshing. tasty.

All this can be attributed to the existence of a "sacred object"-yeast!

Whisky fans who are familiar with the whiskey brewing process know that yeast has always been an important raw material for whiskey brewing. But as one of the three elements of whiskey production (water, barley, yeast), we seem to seldom hear the industry's research on the influence of yeast on the flavor of Scotch whisky. Why does this happen? Are people neglecting the existence of yeast? Or does yeast have no effect on the flavor of whiskey at all? With these questions, let's talk about yeast-an important raw material for whiskey production!

What is sacred yeast?

Yeast generally refers to various single-celled fungi that can ferment sugars and is a natural starter. The history of people using yeast can be traced back to Egypt 4000 years ago. There are many types of yeast, about 56 genera, and more than 1,500 kinds. Among them, Saccharomyces cerevisiae (also known as baker’s yeast or budding yeast) used in wine production is one of the genus, and there are many different strains under the genus. ).

The survival of yeast requires certain conditions, such as temperature, osmotic pressure, sugar concentration, and pH. In whiskey production, in order to ensure the activity of yeast, generally speaking, the temperature when adding yeast is not too high, because high temperature will kill the yeast, so the temperature will be lowered to about 20 ℃ in advance. The fermentation time will also be controlled, not too short, so as to avoid insufficient fermentation. The entire fermentation process is about 40-50 hours, and some wineries may be higher.

Does yeast affect the flavor of whiskey?

Although it is rarely mentioned, the answer is certain: Yeast does add a different flavor to whiskey! In the fermentation process of whiskey, in addition to releasing heat and carbon dioxide, yeast also produces some flavor substances such as acids, aldehydes, esters and non-ethanol alcohols; and the length of fermentation time will also affect the flavor of whiskey. Generally speaking, Long-term fermentation will bring more floral and fruity aromas, while short-term fermentation will add more grain-like aromas.

For example, many craft beers have different flavors because of the use of different yeasts. The Japanese whiskey distillery also mentioned that they have used different types of strains to add more flavor to the liquor. Whether it is theory or example, it is obvious that yeast can affect the flavor formation of whiskey. So the question is: Why in the industry, especially in the field of Scotch whisky, few distilleries "make a fuss" on yeast?

Then I have to mention the "popularity" of commercial yeast!

"Conquer" the commercial yeast of Solvay Winery

Before World War II, whisky distilleries in Scotland basically cultivated their own yeast until DCL launched the new M-Strain yeast. With higher alcohol yield, stronger viability and alcohol tolerance, M-Strain has eliminated the yeast and brewer's yeast cultivated by the winery itself, sweeping the entire Scotch whisky distillery. It wasn't until the 1990s that the better MX-Strain broke this situation.

Purified commercial yeast has higher fermentation efficiency and a more stable fermentation process, not only contracting the needs of most Scotch whisky distilleries, but also being exported overseas. The wineries all use the same amount of yeast, and everyone puts emphasis on the oak barrels and the distillation process that affect the flavor of whiskey. Except for a few forward-looking masters, there are no people who will try their best to innovate on yeast. Woolen cloth!