Yeast is at the centre of the beer making process and an essential home brew supplies ingredient. Without it you could not ferment your beer wort ie malt blends and convert it into modern day beer. Beer yeast are available as both dry and liquid yeasts. Many brewers prefer dry yeasts over liquid yeasts. Dry yeasts if stored correctly can have up to four years life from manufacture. They are often described as active yeasts. Yeast are classified as Ale yeast or Lager yeast. Ale yeast ferment on the top of your wort while Lager Yeast typically ferment at the bottom of your wort.
The main characteristics of yeasts are:
- Flocculation - The rate at which the spent yeasts clump together near the end of fermentation. It may give an insight to beer clearing techniques.
- Attenuation - The degree or percentage estimate of how much malts can be fermented by a particular yeast strain. Rated as High, Medium, and Low.
- Optimal fermentation temperature- the fermentation temperature which produces the desired beer characteristics. Too cool and fermentation will not reach its peak while too hot can produce undesired taste and cloudiness.
- Yeast Flavour Profile - Refers to what the yeast may contribute to the overall beer flavour. Yeast can have a neutral profile or accentuate the characteristics of your beer such as malt taste, hop profiles, dryness, fruitiness, aromas etc.