By HanNing Tung (Brewing Researcher)
If you wish to brew your own craft cider at home, you gonna know this creature: YEAST. The term “yeast” indeed includes many different species and they are all single cell “fungi”, not “bacteria.” Yeast and bacteria are different in two ways: First, yeast has nuclear that bacteria don’t, and the size of yeast cell is significantly bigger than bacteria’s. Second, although they both have cell wall, the composition of yeast cell wall is chitin, while bacterial cell wall is made of peptidoglycan consisting of sugars and amino acids. Therefore, it is not appropriate to use “bacteria” to describe yeast.
In our history, people have been selecting certain yeast species to make bread, beer, cider ,and wine. The most popular yeast species is Saccharomyces cerevisiae which is believed to have been originally isolated from the skin of grapes. A yeast species can have many strains for different usages. Why don’t we just use bread yeast for brewing alcohol? Well, their difference is like golden retriever and poodle: they’re both dogs, but with different traits. Baking yeast strains tend to produce gas rather than wine aroma, while brewing strains can produce significant fruity aroma, and some strains are good at producing a lot of alcohol. Moreover, certain yeast strains have significantly strong alcohol resistance that allows yeast to survive in higher alcohol concentration, while the alcohol concentration limit of yeast fermentation is nearly 20% ABV (Alcohol by volume). Shaoxing wine, which is a traditional Chinese rice wine, has the highest ABV in all kinds of non-distilling alcoholic beverages in the world. The Shaoxing wine makers provide a low temperature environment and a long fermentation period for yeast to reach 20% ABV.
While yeast can naturally be found on fruit skins, today’s commercially used yeasts are usually selected by yeast companies for different purposes, such as baking, brewing, and winemaking. The reason why more and more breweries and wineries tend to use commercial yeast strains rather than natural yeast is that commercial yeast exhibit a more stable performance than natural yeast. A brewer usually applies different yeast strains to brew beer or cider in order to produce rich aroma and alcohol at the same time. ALCHEMA has selected the most suitable yeast strains for you to make cider and mead at home. Therefore, you can make a professional cider for your family and friends by applying special yeast from ALCHEMA. Wanna try it? Stay tuned on our Kickstarter campaign!