Introduction
A single-celled microbe that is a member of the fungus family, known as Yeast. These tiny living organisms play a vital role in many processes, most notably in the kitchen for baking and brewing. While they might all look the same to the naked eye, there’s a diverse range of yeast type, each with its own specific characteristics and uses. We can broadly categorize them into baking yest, brewing yeast, and wild yeast.
Types of Yeast
1. Baking Yeast
This kind of yeast is primarily used in the culinary world for making bread, cakes, pastries, and other baked goods. It’s main job is to cause dough to rise. It achieves this by consuming the sugars present in the dough and releasing carbon dioxide gas as a byproduct. These gas bubbles get trapped in the gluten network of the dough, making it light, airy, and fluffy after baking. Here are the main types of baking yeast you will encounter:
- Active Dry Yeast: This is a very common type of baking yeast that comes in the form of small, dry granules. Before using active dry yeast, it needs to be “proofed” or “activated.” This involves dissolving it in lukewarm water with a little sugar and letting it sit for about 5-10 minutes until it becomes foamy. This step ensures the yeast is alive and ready to work its magic in your dough. Active dry yeast has a longer shelf life compared to fresh yeast, making it a convenient option for home bakers.
2. Instant Dry Yeast (or Rapid- Rise Yeast): Instant yeast is also a dry, granular form of yeast, but unlike active dry yeast, it doesn’t require proofing. You can add it directly to your dry ingredients. Instant yeast is generally more finely ground than active dry yeast and tends to work a bit faster, leading to quicker rising times. It’s a popular choice for its convenience and reliable results.
3. Fresh Yeast (or Cake Yeast): This type of yeast is sold as a compressed block or cake. It has a moist, clay-like texture and a shorter shelf life, typically requiring refrigeration. Fresh yeast is often preferred by professional bakers for its consistent and powerful leavening action, which can contribute to a more nuanced flavor in the final baked product. It needs to be crumbled and dissolved in lukewarm liquid before being added to the other ingredients.
2. Brewing Yeast
Brewing yeast is specifically cultivated for the fermentation of alcoholic beverages, primarily beer and wine. These yeasts consume sugars in the wort (for beer) or grape juice (for wine) and converted them into ethanol (i.e. alcohol) and carbon dioxide. The specific strain of brewing yeast used significantly impacts the final flavor, aroma, and body of the beer or wine. There is a vast array of brewing yeast strains, but they are often categorized into two main types based on their fermentation characteristics. These are:
- Ale Yeast (Saccharomyces Cerevisiae): Ale yeast are top-fermented yeast who tend to rise to the top of the fermentation vessel during the brewing process. They typically prefer warmer fermentation temperatures (around 15-25℃) and produce a wide range of flavors, including fruity, spicy and estery notes. Different ale yeast strains are used to create diverse beer styles.
- Lager Yeast (Saccharomyces Carlsbergensis): Lager yeast are bottom-fermented yeast meaning they settle at the bottom of the fermentation vessel. They prefer cooler fermentation temperature (around 5-9℃) and generally produce cleaner, crisper flavor with less fruity character compared to ales. Lager yeasts are used to brew popular beer styles like Pilsners, Lagers and Bocks.
3. Wild Yeast
Wild yeast are strain of yeast that occur naturally in the environment – on fruits, grains, in the air, and even in our own kitchens. Unlike commercially cultivated baking and brewing yeasts, wild yeasts are not specifically selected or controlled. While they can contributed unique and complex flavors to fermented foods and beverages, their behavior can also be unpredictable.
Sourdough Starter: The most common culinary application of wild yeast is in sourdough bread making. A sourdough starter is a living culture of wild yeasts and lactic acid bacteria that ferments a mixture of flour and water. This fermentation process produces the characteristic tangy flavor and chewy texture of sourdough bread. Maintaining a sourdough starter involves regular feeding with fresh flour and water to keep the wild yeast and bacteria active.
2. Wild Brewer’s Yeast: Also known as Saccharomyces Ellipsoidus Some brewers and winemakers intentionally utilize wild yeasts for a unique and often complex flavor profile in their products. This can involve spontaneous fermentation, where the wort or grape juice is simply exposed to the ambient air and allowed to ferment with whatever wild yeasts are present. Beers like lambics are a prime example of this type of fermentation. However, this method requires careful monitoring to ensure desirable fermentation and prevent spoilage.
Conclusion
In summary, the world of yeast is surprisingly diverse. From the reliable leavening power of baker’s yeast to the intricate flavor contributions of brewing yeast and the unpredictable charm of wild yeast, each type plays a distinct role in creating the foods and beverages we enjoy. Understanding these different types of yeast can empower bakers and brewers to make more informed choices and explore the fascinating possibilities that these tiny organisms offer.