Yeast-Lovers' Guide To Beers: Best Brews For Flavorful Yeast

Yeast is an essential ingredient in beer, and choosing the right strain can make a big difference in the final product. The two main types of yeast used in brewing are Saccharomyces cerevisiae (ale yeast) and Saccharomyces pastorianus (lager yeast). Ale yeast works best at room temperature, producing slightly fruity notes, while lager yeast works at lower temperatures, giving that crisp, clean taste. Ale yeast also has a higher alcohol tolerance and tends to be top-fermenting, rising to the top of the fermenter during fermentation. On the other hand, lager yeast is usually bottom-fermenting, floating towards the bottom of the wort.

Yeast allergies and intolerance

Yeast is a type of fungus that is commonly used in the brewing process. While yeast is an important ingredient in beer, some people may experience allergies or intolerance to it. Here are some details about yeast allergies and intolerance:

Yeast Allergy:

Yeast allergy is a rare condition where the body's immune system reacts to the presence of yeast, a type of fungus. According to the American College of Allergy, Asthma, and Immunology, yeast allergy makes up only a tiny fraction of food allergies. Sources of yeast allergy include bread, alcohol (especially beer and wine), premade stocks, vinegar, fermented foods, certain fruits, and dairy products.

Symptoms of a yeast allergy can vary but may include breathing difficulties, skin reactions, changes in mood, widespread body pain, and anaphylaxis in severe cases. It is important to note that a yeast allergy is different from the more common red, blotchy skin reaction some people experience after drinking alcoholic beverages, which is usually due to sulfur dioxide rather than yeast.

If you suspect a yeast allergy, it is recommended to consult a doctor or allergist for proper diagnosis and treatment. The main treatment for a yeast allergy is avoiding foods containing yeast, and in severe cases, carrying an epinephrine injector to prevent anaphylaxis.

Yeast Intolerance:

Yeast intolerance, or yeast sensitivity, is more common than a yeast allergy. It is caused by the body's inability to properly digest or tolerate yeast in the diet. Symptoms of yeast intolerance may include gastrointestinal issues, discomfort, and unpleasant sensations. Unlike a yeast allergy, yeast intolerance symptoms may take several days to appear.

To diagnose yeast intolerance, it is recommended to consult a healthcare professional and consider an elimination diet, gradually reintroducing yeast-containing foods to identify triggers. A yeast-free diet typically involves avoiding fermented, processed, and aged foods, as well as reducing sugar intake to limit the growth of natural yeasts in the body.

In summary, while yeast plays a crucial role in brewing beer and contributes to its unique characteristics, some individuals may experience yeast allergies or intolerance. These conditions can range from mild gastrointestinal issues to severe anaphylactic reactions. If you suspect any sensitivity to yeast, it is important to seek medical advice and make informed choices about your diet and beverage consumption.

Lager yeast

One popular lager yeast is the German Lager Yeast, which is one of the most widely used lager strains in the world. It can be used in almost any lager style and tends to produce clean and crisp beers. Another well-known lager yeast is the Saflager W-34/70, which is a robust yeast that can be forgiving for new brewers. It ferments clean and remains stable even with temperature fluctuations, making it a good choice for steam beers and pseudo-lagers.

When choosing a lager yeast, it is important to consider the desired flavour profile and the specific characteristics of the yeast. For example, some lager yeasts may produce more esters or phenolic flavours, while others may be better suited for warm or cold fermentation. The choice of yeast will depend on the style of beer being brewed and the desired flavour profile.

Ale yeast

There are a huge variety of ale yeast strains, each with its own unique characteristics. For example, some strains are classified as "clean" fermenters, producing lager-like beers using ale techniques and fermentation times. These strains include WLP001 (California Ale), WLP029 (German Ale/Kölsch), and WLP051 (California V Ale).

Other strains, such as WLP002 (English Ale), WLP004 (Irish Ale), and WLP005 (British Ale), are known as fruity, group 2 yeasts, adding a lot of character to the beer. These yeasts create more compounds that are excreted from the yeast cells, resulting in more complex flavours.

When choosing an ale yeast, it's important to consider the desired flavour profile and the specific requirements of the beer style being brewed. Additionally, proper aeration of the wort prior to pitching and controlling the fermentation temperature are crucial for achieving the desired flavour and minimising off-flavours.

Yeast characteristics

Ale Yeast

Ale yeast, or Saccharomyces cerevisiae, is distinguished by its unique flavour production. Ale yeast ferments quickly, consumes the correct profile of sugars, tolerates moderate alcohol levels, and can survive the anaerobic conditions of fermentation. Ale yeast is also known for its ability to top ferment, rising to the top of the fermenter during the first 12 hours of fermentation. This allows brewers to collect the yeast from the top through a practice called top cropping.

Ale yeast strains can be further categorised into "clean" fermenters and "fruity" fermenters. Clean fermenters, such as the WLP001 (California Ale) and WLP029 (German Ale/Kölsch) strains, produce a small quantity of flavour compounds and are popular for producing lager-like beers using ale techniques and fermentation times. Fruity fermenters, such as the WLP002 (English Ale) and WLP004 (Irish Ale) strains, produce more flavour compounds and can add a lot of character to the beer.

Lager Yeast

Lager yeast, or Saccharomyces pastorianus, ferments at the bottom of the fermenter and works at much lower temperatures than ale yeast. Lager yeast utilises the sugars found in wort more fully, giving lager beers their characteristic clean, crisp taste. Lager yeast does not usually collect at the top of the fermenting beer and is known as a bottom fermenter.

When choosing a yeast strain, it is important to consider the desired flavour contribution, as different strains will produce varying levels of esters, phenolics, diacetyl, and acetaldehyde. Esters impart flower and fruit-like flavours and aromas to the beer, while phenolics can be responsible for off-flavours such as clove and banana. Diacetyl gives a "butterscotch" flavour, and acetaldehyde imparts a grassy or green apple flavour to the beer.

In addition to flavour contributions, other yeast characteristics to consider include attenuation, flocculation, and optimal fermentation temperature. Attenuation refers to the degree to which the yeast ferments the fermentable sugars in the wort, and it can be measured through hydrometer readings. Flocculation refers to the clumping of yeast cells into clusters, which usually happens at the end of fermentation, and it determines how quickly the beer will clear. Optimal fermentation temperature refers to the ideal temperature range for the yeast to ferment the beer, and it is crucial for producing the desired flavours and avoiding off-flavours.

Yeast and beer styles

Yeast is what makes beer so fascinating, delicious, and nutritious. Humans brewed for thousands of years before understanding the role of yeast in the process.

Ale Yeast

Ale yeast, or Saccharomyces cerevisiae, includes bread yeast, distillers yeast, and many laboratory yeast strains. Ale yeast is distinguished by its unique flavor production. Ale yeast ferments quickly, consumes the correct profile of sugars, tolerates moderate alcohol levels, and can survive the anaerobic conditions of fermentation.

Ale yeasts are top-fermenting, rising to the top of the fermenter during fermentation. They have a temperature range of 10-25°C, with an ideal range of 18-22°C, which is easy to maintain. They are used to brew ales, stouts, porters, wheat beers, Altbier, and Kölsch.

Ale yeast strains differ in performance, flocculation, attenuation, and flavor profiles. They can produce fruity esters or clean profiles with very little character added.

Lager Yeast

Lager yeast, or Saccharomyces pastorianus, works at much lower temperatures (8-15°C) and is usually bottom-fermenting. Lager yeasts utilize the sugars in the wort more fully, giving that clean, crisp taste associated with the style.

Lager yeasts do not reproduce as quickly as ale yeasts and tend to settle at the bottom of the fermenter. The colder temperatures inhibit the production of chemical products or off-flavors, resulting in a "cleaner" taste than ales. Lager yeasts are used to brew lagers, pilsners, bocks, Märzens, and Dortmunders.

Other Yeast Strains

There are also yeast strains that are not ale or lager, such as Brettanomyces bruxellensis, which is used to create "brett" style or sour beers. Bacteria-positive yeasts, which contain a bacterial strain, are also used for creating sour beers.

Yeast Characteristics

When choosing a yeast strain, it's important to consider the desired flavor contribution, such as esters, phenolics, diacetyl, and acetaldehyde. Proper aeration of the wort prior to pitching and controlling the fermentation temperature are key to producing the desired flavors.

Other factors to consider when choosing a yeast strain include attenuation, alcohol tolerance, flocculation, and optimal fermentation temperature. Each yeast strain has its own characteristics, and understanding these will help you make the right selection for the style of beer you want to produce.

Frequently asked questions