I previously mentioned in my last post that I’m working my way through Yeast: The Practical Guide to Beer Fermentation by Chris White & Jamil Zainasheff. It is a great reference and is helping me in understanding how important those tiny wee guys are when it comes to brewing.
As I work my way through the book I am taking notes… and low and behold, here they are:
Choosing Yeast
Before you choose a yeast strain for your fermentation, it is importance that you know what you are brewing – this may seem like an obvious statement, but it is extremely important. Try answering some of the following questions to help you pin point what you need from your yeast:
- Is your beer going to be dry and hoppy?
- Is your beer going to be sweet and malty?
- Is your beer going to be clean or cloudy?
- Is your beer going to be high or low in alcohol?
By knowing the answer to these questions you can start to explore the strains available and find one that will provide you with the correct outcome.
When selecting yeast consider what each strain offers in terms of:
- Attenuation
- Flavour profile
- Flocculation (aggregation of yeast into larger clumps)
- Temperature range productivity
Different Yeast Strains
Saccharomyces Cerevisiae – Ale Yeast to you and me. This is a large group that contains yeast that works for bread, distilling and labs.
Ale yeasts typically ferment quickly, consuming the correct profile of sugar and tolerate levels. It is normally a top fermenting yeast – the foaming head produced in fermentation is perfect for top cropping.
The temperature range in which Ale Yeasts generally produce their best flavours when fermenting is 18-21C
Clean Ale Strains
Popular in the USA. Produces low fruit flavours and fusel alcohol. This strain is good for brewers looking to showcase the flavours of their hops and malt.
The strain is known to produce a trace amount of sulphur when exposed to stressful conditions.
Fruity Ale Strains
Traditionally used in English brewing, but it gaining steady traction in the USA. Produces more interesting flavours and aromas than Clean Ale Yeast strains. The fermentation process is generally quicker as well.
As a general rule, Fruity Ale Strains produce clearer beer, but has been known to leave behind more by-products. The strain is often described as leaving behind hints of honey and citrus.
Hybrid Ale Strains
Typically, this is a strain that ferments at a cooler than average temperature. Produces a clear, almost lager like beer.
Phenolic Ale Strains
Historically used in Belgian ale and German wheat beer. The main characteristic is an increase in phenol – an aromatic compound. This is from the same class of compounds as used in antiseptics and some drinkers describe the flavour (plus aroma) of beers brewed using this yeast strain as medicinal.
Most phenolic beer strains do not flocculate well, leaving behind a cloudiness to the beer – this is something which is often aimed for when brewing a German wheat beer.
Eccentric Ale Strains
This strain is typically any Ale yeast that has not been pigeonholed into any of the previous categories. Again, this strain is most commonly used in Belgian-esque ales. This is due to the fact that it produces some unusual flavour compounds. For example:
- Earthy
- Barnyard
- Sourness
Deals well with extremely high gravity wort.
And… that’s that for this post. Apologies – I sometimes struggle to conclude a post concisely. So yeah. Done.
