What Are the Main Types of Yeast Used in Brewing?

When it comes to brewing, as the saying goes, "It takes yeast to tango." Understanding the main types of yeast used in brewing can significantly impact the flavor and profile of your beer. From the classic ale yeast with its expressive fruity esters to the clean and crisp lager yeast, each type brings its own unique characteristics to the brew. But what about the lesser-known Belgian yeast strains, the specialized wheat beer yeasts, and the intriguing hybrid varieties? Let's explore how these different yeast types can shape the outcome of your next brewing experiment.

Ale Yeast

Ale yeast, also known as Saccharomyces cerevisiae, showcases remarkable versatility in its fermentation capabilities, making it a cornerstone in the brewing industry. This type of yeast is particularly favored in ale production due to its ability to ferment under anaerobic conditions efficiently. Ale yeast strains play a crucial role in determining the flavors and aromas of the final beer product. Each strain of ale yeast brings its own unique characteristics to the fermentation process, influencing the taste profile of the beer.

One notable technique associated with ale yeast is top cropping. Certain ale yeast strains are well-suited for top cropping, a method where the yeast is skimmed off the top of the fermenting beer. This technique is employed to collect yeast for future use while allowing the beer to clarify. Understanding the ideal pitching rate for ale yeasts is essential for achieving optimal fermentation. Generally, pitching rates ranging from 5 to 10 million cells per milliliter are recommended to ensure a healthy fermentation process and desirable beer outcomes.

Lager Yeast

Saccharomyces pastorianus, commonly known as lager yeast, distinguishes itself in the brewing process through its unique characteristics and fermentation requirements. Lager yeast is a type of bottom-fermenting yeast that works best at low to medium temperatures, typically between 50–55°F (10–13°C). This cold fermentation process is in stark contrast to the warmer fermentation temperatures used by ale yeast strains.

First isolated in 1881 by Emil Christian Hansen, lager yeast played a pivotal role in revolutionizing beer production. One of the distinguishing features of lager yeast is its tendency to settle at the bottom of the fermentation tank, unlike ale yeast which rises to the top.

When it comes to flavor profile, lager yeast produces beers with fewer esters and fusel alcohols compared to ale yeast strains. This results in a cleaner and crisper taste in the final product. To ensure efficient fermentation, it is crucial to pitch lager yeast at an optimal rate, typically between 15–20 million cells per milliliter.

Lager brewing, characterized by the use of lager yeast, is a meticulous process that demands precision and attention to detail. By understanding the unique characteristics and requirements of lager yeast, brewers can craft a wide range of flavorful and refreshing beers.

Belgian Yeast Strains

Belgian yeast strains showcase a complex array of flavors and aromas in the beers they ferment, distinguished by their characteristic phenol, clove, esters, fusel alcohols, and earthy notes. These strains, often used in Trappist beers, contribute unique characteristics to the brew. Esters and phenolics are prominent in Belgian strains, offering fruity and spicy notes that are highly desirable in a variety of beer styles.

When working with Belgian yeast strains such as WLP500 (Trappist Ale) and WLP530 (Abbey Ale), it is crucial to consider the fermentation temperature. Controlling the fermentation temperature is essential to manage the production of fusel alcohols, which can lead to off-flavors if not kept in check.

Unlike lager yeasts or ale yeast strains, Belgian strains typically have poor flocculation characteristics, requiring a higher pitching rate to ensure complete fermentation. This higher pitching rate helps to achieve the desired attenuation levels and avoid stuck fermentations.

To craft exceptional Belgian-style beers, brewers must find the right balance of esters, phenolics, and other compounds that Belgian yeast strains offer. Embracing the creativity that these strains allow can lead to the development of beers with unparalleled complexity and depth of flavor.

Wheat Beer Yeast

Wheat beer yeast strains play a crucial role in shaping the distinctive flavors and characteristics of wheat beer styles, offering complexity and unique profiles to the final brew. These strains are known for producing a range of flavors such as wild yeast, phenolic, and clove notes, which are particularly prominent in styles like Hefeweizen. With approximately half a dozen different wheat beer yeast strains available for brewers to choose from, each strain contributes its own nuances to the flavor profile of the beer.

One key characteristic of wheat beer yeast strains is their tendency not to flocculate well. This means that they do not settle out of the beer easily, leading to the characteristic cloudiness often associated with wheat beers. Popular strains like White Labs' WLP300 (Hefeweizen) and WLP380 (Hefeweizen IV) are sought after for their ability to impart these unique flavor profiles to the beer.

Furthermore, wheat beer yeast strains typically produce minimal amounts of alpha-acetolactate, which is responsible for the butterscotch-like flavors sometimes found in beer. This results in a cleaner flavor profile in wheat beers, allowing the other characteristics like clove and phenolic notes to shine through without being overshadowed.

Hybrid Yeasts

Hybrid yeasts, blending ale and lager yeast strains, offer brewers the opportunity to craft beers with distinctive and innovative flavor profiles while enhancing brewing efficiency and product quality. By combining the best traits of ale yeasts and lager strains, hybrid yeasts provide brewers with a versatile tool to create beers with unique flavor profiles that cannot be achieved with traditional yeast strains alone.

One of the key advantages of hybrid yeasts is their ability to ferment at both ale and lager temperatures, showcasing cold tolerance that allows for greater flexibility in the brewing process. This cold tolerance not only aids in the fermentation process but also contributes to the development of flavors that are typically associated with lager beers, such as crispness and clean fermentation character.

Moreover, hybrid yeasts are engineered to improve fermentation efficiency, resulting in a more consistent and predictable brewing performance. This genetic manipulation of yeast strains enables brewers to fine-tune their processes and achieve desired flavor outcomes with precision. In the realm of modern brewing practices, hybrid yeasts have become indispensable for pushing the boundaries of beer styles and delivering products of exceptional quality.