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The Importance of Yeast in Beer Making: A Connoisseur's Perspective from McAllister Brewing Co.

By Seth Montz, March 27, 2023


As a beer connoisseur, I cannot stress enough the importance of yeast in the beer-making process. Yeast is responsible for the fermentation of beer, which ultimately gives it the unique taste and nuance of flavors that we all know and love. As most of us know, yeast’s primary job is to convert sugars from the wort into alcohol, but what some may not know, is what goes into that process to make it happen.


We at McAllister Brewing Co. understand the crucial role yeast plays in our beer-making process. We use a variety of yeast strains to create our flavorful and distinctive brews.


Yeast strains are broken into 2 main types; ale yeast, and lager yeast. There is also a third type which is grouped together as wild yeast. The main difference between the ale and lager yeast is top fermenting vs bottom fermenting. What this means is ale yeast, which is top fermenting, ferments at a higher temperature producing more flavorful and complex esters. Each style of ale has its own individual yeast strain. A great example would be our Belgian Style Peach Wit which uses Belgian ale yeast to produce fruity esters which gives the beer its depth and complexity.


Lager yeasts, which are bottom fermenting, ferment at colder temperatures. These yeast strains produce clean, dry profile beers with very little off flavor or ester profiles. Most of these yeast strains originated from southern Germany, or the surrounding areas, where lager production was capable due to its climate, and the ability for brewers to ferment beers at colder temperatures before the advent of refrigeration. Pilsner yeast, the most common lager brewing yeast originated from Plzeň Czech Republic which was the birthplace to Pilsner Urquell, the benchmark for all pilsner beers.


Wild Yeast is a catch all for all other yeasts found in the wild that haven’t been cultivated and standardized for brewing, distilling, or baking. Wild yeast is in the air we breathe, the surfaces we touch and even in and on our bodies. These strains can be harvested from anywhere. Like their name suggests, these yeast strains are unpredictable and can range from making excellent, unique, tasting beers to absolutely, putrid, undrinkable concoctions. Wild yeast strains aren’t as common in brewing and are mainly used for experimental beers like our Never Nude series, where they have been harvested anywhere from old wood to gravestones! A lot of times wild yeast is paired with different bacteria strains like brettanomyces, lactobacillus, and pediococcus to produce sour beers like our Gerardus Mercarter Flanders Style Red Sour Ale. These yeast and bacteria require special handling since they tend to be more aggressive and unpredictable then standard brewing yeast; most brewers will use completely different equipment and systems to produce these beers as to not introduce the strains to their main production area. These yeasts tend to need time to develop their unique flavor profile. Unlike brewing yeast which can finish a beer in the matter of days to weeks, true sour beer and wild fermented beers tend to be aged for years developing their flavors over time.


Yeast, no matter what strain or type all require the same thing. Constant temperature, adequate oxygen, and the right amounts of yeast to fully attenuate the wort to finish the beer. Controlling those aspects, as well as impeccable sanitary practices, allows the brewer to make the type of beer they are trying to create. Just a couple of degrees difference can change the environment for the yeast affecting how they consume the sugars in the wort which will produce different flavors. German Hefeweizens are a great example of this. A Hefeweizen fermented at lower temperatures will have clove like and spicy notes to it. If the same Hefeweizen is fermented at a higher temperature it will have notes of banana and fruit.

One of the ways that McAllister Brewing Co. stands out is by experimenting with different yeast strains and fermentation methods to create unique and flavorful beers. They use traditional brewing techniques combined with modern technology to ensure that their beers are of the highest quality.


Yeast is an essential ingredient in the beer-making process producing the flavor and alcohol content of the beer. Brewers must carefully choose and handle the yeast to create the desired taste profile.McAllister Brewing Co. is a prime example of a brewery that understands the importance of yeast and uses it to create outstanding and flavorful beers. So next time you enjoy a cold brew, take a moment to appreciate the tiny yeast cells that made it all possible. Cheers!


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