Yeast varieties: what makes them different?
These days there are a wide range of yeasts for homebrewers to use, it can even be a bit daunting. We are a far cry from when homebrewers had to use baker’s yeast because there was simply no market for small quantities of brewer’s yeast. But what exactly are the differences between these yeasts?
First you have to understand what yeast is, a single celled organism which is classed as a fungus. It is useful for various cooking processes as it breaks down sugars creating new substances. This of course includes alcohol, but also esters which are a big part of why we have such a large range of smells and flavours. You may also get some yeast producing secondary compounds, which may be broken down as the fermentation goes on or add a unique quality to the beer.
So what are the differences between the yeasts? Well that is a never ending question. It is very easy to breed new strains of yeast so you will find a near endless variety. We certainly can put things in general boxes but there will always be those who break the rules. We’ll give you a few examples so you know where to generally stand.
English Ale yeast seems like a good place to start, in many ways is your bog standard yeast but that is not to say it is boring. On the contrary, it does a little bit of everything which is why starting here makes sense. Ale yeasts prefer warm temperatures, usually not over 30C but enough to make sure they get some energy to cause reactions. They’ll generally produce a moderate amount of alcohol, we call the percentage of sugars turned into alcohol attenuation. Some strains can be very attenuative, but in general a decent amount of sugar is left so the beers are still somewhat sugary and less dry. You also find they produce a huge range of flavours, this is because English ale yeasts produce a lot of esters. They also tend to create clearer beers, some may still float in suspension but you generally won’t get strong yeasty flavours.
Lager yeast is a bit more specialised. While ale yeasts will ferment on the top of our brew, lager yeasts will ferment on the bottom. It goes with another important trait, in that they also work at much cooler temperatures. This is partly due to the yeast’s origins, as the original strains were produced from beers brewed in the winter. The yeasts that could survive lower temperatures and not die off at the top would be scooped up and used next time. This isn’t the only interesting trait of lager yeast though. Many will produce secondary compounds such as sulphur, which in this case can create a weird off egg smell. The brew itself is fine though, generally these compounds will be broken down again as your fermentation continues. You will also find that lager yeasts produce less esters, which is why they have a more clean and crisp taste.
Belgian yeast is a more unusual strain, they often stand out far more that other varieties which is not always to people’s taste. In some ways it is similar to English Ale yeast being top fermenting yeast which prefers warm temperatures. They also tend to be high in esters and phenols. But it does have some interesting features. The yeasts are nearly all less attenuative than you’ll see from English Ale yeasts, so more often you will get cloudy beers. This works with what Belgian Ales try to aim for making it an acquired taste. They also tend to be highly attenuative, this will lead to very alcoholic drinks and also very dry. Belgian yeasts can produce some of the more unique ales, dry, alcoholic beers with a lot of flavours. It opens up a lot of possibilities if you get into them.
What yeast you use can have a huge effect on the beer you make, so it is great to take advantage of the large range available. Our kits offer lots of different yeasts including lager and Belgian yeasts, so why not give something different a try.