How to Improve Beer Quality and Consistency with Inactivated Specific Yeasts

Brewing basics

Brewing beer is easy. Four simple ingredients, and a process so straightforward that the earliest beers were brewed by accident when wet grains started to germinate and ferment. Yet, brewing consistently high-quality beer is a different challenge, and the modern brewing process extends far beyond the simple equation of beer = water + malt hops + yeast.

Modern malts are consistently high quality, and we have never had more diversity of flavor from different hop varieties. It is common now for brewers to adjust their water profile to achieve specific sensory impacts. A wide range of unique yeast strains are available to suit any beer style, and brewers are controlling fermentation parameters to achieve specific flavor profiles and encourage biotransformation.

Many brewers also use nutrients, enzymes, and process aids to improve yields, increase efficiency, and achieve better product quality and consistency. Inactivated specific yeast products are an emerging category that has the potential to further enhance and improve beer flavors.

What are ISY products?

When yeast is inactivated, it can be divided into different fractions with specific characteristics (whole yeast autolysate, cell wall fractions, protein fractions, etc.). Inactivated Specific Yeasts (ISY) are blends of specific yeast fractions that can be used to change or preserve the flavor and sensory characteristics of the beer. While nutrients may be yeast derived, ISY products are not nutrients.

Boost body and drinkability with ISY Enhance™

In 2023, Lallemand Brewing released ISY Enhance™, which is rich in mannoproteins that contribute to body and mouthfeel. ISY Enhance™ has become popular in low and no-alcohol beers to increase body and complexity in styles that are often lacking character. In IPA styles, ISY Enhance™ helps improve balance and reduce hop burn and astringency. As a whirlpool addition, ISY Enhance™ is easier to use than maltodextrin and generally preferred for sensory impact. In any beer style, ISY Enhance™ can improve drinkability and side-by-side tastings show a general preference for beers brewed with this product.

Get rid of off-flavors with ISY S-Reduce

In June 2025, Lallemand Brewing launched ISY S-Reduce, which contains a cell-wall fraction enriched in biologically bound copper. Copper reacts with sulfur compounds allowing ISY S-Reduce to efficiently reduce sulfur off-flavors from hydrogen sulfide (H₂S, rotten egg smell), dimethyl sulfide (DMS, cooked vegetable smell), or mercaptans (sewer drain odors). While higher copper levels in finished beer can reduce product stability, the biologically bound copper in ISY S-Reduce can be easily removed from the beer after treatment resulting in clean, crisp, sulfur-free beers.