What Is Ale Yeast?

While sitting in your favorite hole in the wall or local brewery, you may find yourself wondering how your favorite beers come to be. What is ale yeast? It is a single celled organism, a living creature, that metabolizes, reproduces and lives in beer. Ale yeast converts sugar into alcohol and carbon dioxide during the fermentation stage of the brewing process.

Ale yeast is one of two types of yeast used to make beer. It is known as top-fermenting yeast, and less commonly referred to saccharomyces cerevisiae. Top-fermenting yeast is used to make ales and stouts and is similar to yeast used to make bread. Top-fermenting yeast is where deeper, more heavy brews get their flavor. Strains of ale yeast that are not cultivated will basically ruin your brew, as they disrupt brewing and can add too much carbonation and an off taste at the least.

Top-fermenting yeast is named for its desire to group at the surface of the brew for the first few days of the fermenting process. Top fermenting, or ale, yeast is most effective in a temperature range of 55-75 degrees Fahrenheit, so be diligent about keeping it so. Ale yeast that is too cold will cease to work. Being meticulous about the intricate needs of ale yeast will ensure a most tasty and enjoyable beer.

The next time you are taking a sip, or gulp, of your favorite beer, think about all of the miraculous work these tiny creatures have done for you. The process of beer making is a scientific and natural wonder where yeast takes center stage.

Sources:

Beer Advocate

Genome Database - Yeast