The highest attenuation yeast, or the yeast that can ferment the most sugars, is generally found among lager yeasts. Lager yeasts are known for their ability to ferment at cooler temperatures and produce clean, crisp flavors in beer. While most ale yeasts typically have an attenuation range of around 70-80%, some lager yeasts can reach attenuation levels upwards of 84%.
Among the lager yeasts, there are a few strains that are particularly known for their high attenuation capabilities. The Fermentis strains S-23, W-34/70, and S-189 are often mentioned as the top contenders in this regard. These strains have been specifically selected and cultivated to perform well under lager fermentation conditions.
Attenuation refers to the percentage of sugars that the yeast is able to ferment during the fermentation process. Yeast consumes sugars and converts them into alcohol and carbon dioxide through a process called fermentation. The higher the attenuation, the more sugars the yeast is able to consume and convert.
In my experience as a brewer, I have worked with these high attenuation lager yeasts and have seen their impressive fermentation capabilities firsthand. I have used the S-23 strain, for example, in a pilsner recipe where I was aiming for a very dry and crisp finish. The S-23 yeast performed exceptionally well, attenuating the beer to a level that provided the desired dryness without any residual sweetness.
It's important to note that attenuation is just one factor to consider when selecting a yeast strain for brewing. Other factors such as flavor profile, temperature range, and flocculation characteristics should also be taken into account. The choice of yeast strain will ultimately depend on the desired style and flavor profile of the beer being brewed.
To summarize, the highest attenuation yeast strains are typically found among lager yeasts, with Fermentis strains S-23, W-34/70, and S-189 being known for their ability to reach attenuation levels upwards of 84%. These strains have been selected and cultivated specifically for their high fermentation capabilities, making them popular choices for brewers looking to achieve a dry and clean finish in their lagers. However, it's important to consider other factors beyond attenuation when selecting a yeast strain for brewing.