The magic of beer yeast
In ancient times, beer brewing sticks were passed on as family heirlooms, because it was believed that brewing with the family stick would preserve the quality of the beer over generations. Much later it was discovered that the stick retained the family yeast culture which did the magic brewing.
Yeast (Saccharomyces cerevisiae) is a microorganism belonging to the category of fungus, and it has a unique ability to survive with or without oxygen. Yeast consumes sugars like maltose and releases carbon dioxide and alcohol as by-products. This process is known as fermentation and it is the fundamental science behind beer making.
Along with carbon dioxide and alcohol, fermentation also results in the production of esters, phenols, ketones and fatty acids.
Esters impart the fruity tones and phenols give the spicy touch to the
Diacetyl ketones often result in butter or butterscotch like flavours and can be
of preference sometimes, but diacetyl can also result in stale or raunchy tones as the beer ages.
Ale and lager yeasts
Two main types of yeast used in beer making are Ale and Lager yeasts.
Ale yeasts require warmer temperature for fermentation. Ale is also known as top-fermenting yeast as it acts at the top layer inside a fermenter.
Conversely, lager yeast can withstand lower temperatures and mostly work at the bottom of the fermenter.
Choice of a yeast strain largely determines the flavour and aroma of a beer.
It mostly depends upon the brewer what kind of beer they prefer to develop in their brewery.
For example, Belgian strains impart fruity flavours, while some German strains are
known for strong and spicy tones. Malt barley is the most common sugar source for beer making, however, brewers also use wheat for fermentation.
Some intricacies to understand for beer making
Before you decide to buy your brewer’s yeast, it is crucial to understand the following terms related to yeast fermentation:
Attenuation- It is the percentage of sugar (malt or wheat) that a particular strain can convert to ethanol and carbon dioxide. Most yeast strains can attain an attenuation of 65 to 80%.
Flocculation- Yeast can clump and settle at the bottom of the fermenter after the
fermentation is complete. Different strains have different flocculation rates and highly flocculant yeasts will settle faster at bottom requiring more culture to added before the fermentation is complete.
Lag time- Time from pitching the yeast into the fermenter to the beginning of primary
fermentation is known as lag time. Long lag time suggests poor fermentation
Therefore, it is recommended that fermentation intricacies are carefully analysed
before you select a yeast strain for brewing.
Yeasts for your home brewing
At Hobby Hydro we sell great quality yeast cultures for both ale and lager beer making.
We recommend American ale yeast for brewing a top-quality and foamy ale with low diacetyl. Wheat beer yeast is wonderful for brewers looking for ester and phenol flavour notes in their beer.
Further, we recommend German lager yeast for producing fruity lagers with good retention on the palate. Apart from the recommended yeast cultures, we have a large variety of yeasts to choose from and we would be more than happy to assist our customers with their selection of a perfect beer brewing kit.
Contact us at Hobby Hydro to know more about beer yeasts.