What Yeast Strain Varieties are Used in Beer Brewing?

Beer brewing is an intricate and fascinating process that combines various ingredients to create the beloved beverage enjoyed worldwide. One crucial ingredient in this process is yeast, a microorganism responsible for converting sugars into alcohol and carbon dioxide. However, not all yeast strains are created equal when it comes to brewing beer. Brewers carefully select specific yeast varieties that play a significant role in determining the flavor, aroma, and overall characteristics of the final brew. In this exploration, we will delve into the world of yeast strain varieties used in beer brewing, uncovering the unique qualities and contributions they bring to the art of crafting exceptional beers.

Understanding the Role of Yeast in Beer Brewing

In the world of beer brewing, yeast plays a critical role in the fermentation process. It is responsible for converting sugars into alcohol and carbon dioxide, giving beer its distinct flavors, aromas, and carbonation. Without yeast, beer would simply be a sweet, unfermented liquid.

Yeast is a microorganism that belongs to the fungi kingdom. In the context of beer brewing, there are two primary types of yeast: ale yeast and lager yeast. These two yeast strains have different characteristics, and their selection greatly influences the style and profile of the beer being produced.

Ale Yeast: The Versatile Fermenter

Ale yeast, scientifically known as Saccharomyces cerevisiae, is the most commonly used yeast strain in beer brewing. It is a top-fermenting yeast, meaning it rises to the top of the fermentation vessel during the fermentation process. Ale yeast is known for its ability to ferment at higher temperatures compared to lager yeast, typically between 15°C and 24°C (59°F and 75°F).

The versatility of ale yeast allows for a wide range of beer styles to be brewed. It produces a variety of flavors and aromas, including fruity esters and spicy phenols. These characteristics contribute to the complexity and diversity found in ales, such as pale ales, IPAs, stouts, and porters.

Lager Yeast: The Cool Fermenter

Lager yeast, scientifically known as Saccharomyces pastorianus, is a bottom-fermenting yeast that operates at cooler temperatures, typically between 7°C and 13°C (45°F and 55°F). Unlike ale yeast, lager yeast ferments slowly and settles at the bottom of the fermentation vessel.

Lager yeast is responsible for the creation of crisp, clean, and refreshing beers. It produces fewer fruity esters and phenols compared to ale yeast, resulting in a more subdued flavor profile. This makes lagers a popular choice for those who prefer a lighter, less assertive beer, such as pilsners, bocks, and Märzens.

Varieties of Yeast Strains Used in Beer Brewing

Now that we have a basic understanding of the two primary types of yeast used in beer brewing, let’s explore some specific yeast strains and their unique characteristics.

Ale Yeast Strains

1. Saccharomyces cerevisiae (American Ale): This yeast strain is known for its clean fermentation profile, producing mild fruity esters and a balanced flavor. It is commonly used in American-style ales, such as American pale ales and IPAs.

2. Saccharomyces cerevisiae (English Ale): English ale yeast strains contribute to the classic flavors and aromas found in traditional English ales. They produce fruity esters, often described as stone fruit or apple-like, and can add a subtle maltiness to the beer.

3. Saccharomyces cerevisiae (Belgian Ale): Belgian ale yeast strains are famous for their unique and complex flavors. They produce a wide range of fruity esters, spicy phenols, and occasionally a touch of tartness. These strains are commonly used in Belgian-style ales, such as Saisons, Dubbels, and Tripels.

Lager Yeast Strains

1. Saccharomyces pastorianus (German Lager): German lager yeast strains are known for their clean and crisp fermentation characteristics. They produce a well-rounded, malty flavor profile with minimal fruity esters. These strains are commonly used in German-style lagers, including Oktoberfest and Munich Helles.

2. Saccharomyces pastorianus (Czech Lager): Czech lager yeast strains contribute to the distinctive flavors found in Czech-style lagers, such as Pilsners. They produce a delicate balance of maltiness and hop bitterness, resulting in a refreshing and flavorful beer.

3. Saccharomyces pastorianus (American Lager): American lager yeast strains are often selected for their ability to produce clean, light-bodied beers with minimal flavors and aromas. They are commonly used in American-style lagers, such as Budweiser and Coors.

The Impact of Yeast Selection on Beer Styles

The choice of yeast strain is crucial in determining the style and characteristics of the beer being brewed. Brewers carefully select yeast strains based on the desired flavor profile, aroma, and fermentation characteristics.

For example, if a brewer is aiming to create a hop-forward IPA with citrusy and tropical fruit flavors, they may choose an American ale yeast strain known for producing clean fermentation profiles and enhancing hop aromas. On the other hand, if they are brewing a traditional Belgian Dubbel with complex fruity and spicy notes, a Belgian ale yeast strain would be a more suitable choice.

Furthermore, some breweries develop their own proprietary yeast strains, which they guard as closely as their secret recipes. These unique yeast strains help differentiate their beers from others in the market, offering consumers a truly distinctive drinking experience.

FAQs

What yeast strain varieties are commonly used in beer brewing?

In beer brewing, several yeast strain varieties are used to create different styles and flavors. Some of the most commonly used ones include:

1. Saccharomyces cerevisiae: This yeast strain is widely used in brewing and produces a range of beer styles, including ales. It ferments at warmer temperatures, typically between 68-75°F (20-24°C). Different strains within this species can produce varying aromas and flavors, contributing to the diversity of beer profiles.

2. Saccharomyces pastorianus: This yeast strain is essential for brewing lagers, which are fermented at cooler temperatures, usually around 45-55°F (7-13°C). It is a bottom-fermenting yeast, and it provides the characteristic clean and crisp flavors commonly associated with lagers.

3. Brettanomyces (Brett): Brettanomyces is a wild yeast strain often used intentionally to produce unique and complex flavors in certain beer styles, such as Belgian-style or sour beers. It can create funky, fruity, and sometimes barnyard-like aromas and tastes, adding depth and complexity to the final product.

4. Pichia pastoris: While not as widely used as the previous strains, Pichia pastoris is gaining popularity in the craft brewing industry. It is primarily used in the production of specialty and experimental beers due to its ability to ferment at colder temperatures and its unique flavor contribution.

5. Other strains: Besides the aforementioned strains, there is a vast number of yeast laboratories that offer specialized strains for specific beer styles or experimental brewing. These include ale strains for different ale styles like IPAs and stouts, as well as hybrid strains that possess characteristics between ale and lager yeast.

How do brewers choose which yeast strain to use?

The choice of yeast strain depends on several factors, including the desired beer style, flavor profile, fermentation temperature, and the brewing process. Brewers typically consider the flavors and characteristics associated with specific yeast strains, aiming to compliment or enhance the desired beer style. They also consider practical considerations such as the time needed for fermentation and the yeast’s tolerance to alcohol and temperature. Additionally, brewers may experiment with different yeast strains to create unique and innovative flavors or to recreate historical styles.

Can brewers use different yeast strains in combination?

Yes, brewers often experiment with using multiple yeast strains in combination to create unique flavors and characteristics in their beers. This technique is known as co-fermentation and allows brewers to explore new possibilities by blending the attributes of different yeast strains. By carefully selecting and blending compatible yeast strains, brewers can create complex and layered flavors that may not be achievable with a single strain alone. This technique requires careful monitoring and attention to fermentation conditions to ensure the desired flavors are achieved.

Are there any considerations for yeast strain selection during homebrewing?

Homebrewers have access to a wide range of yeast strains, and the selection process can be based on personal preferences and desired beer styles. When choosing yeast strains, homebrewers should consider factors like fermentation temperature control, yeast viability, and the ability to handle the specific strain’s fermentation requirements. It is also recommended to research and gather information on specific yeast strains to gain insights into their flavor profiles and optimal fermentation conditions. Homebrewers can experiment with different yeast strains and techniques to develop their own unique beers.