Why are there so many different yeast options?

[Elysium82]

I am not complaining...I am just genuinely curious.

My understanding was that it is only lager and ales that one can make (which is the generic truth). Then when I go to a website to shop for yeast, I find at least 10 different types of yeast in the ale and lager categories. How is that possible? What makes a yeast different within these 2 main categories?

 

[EnglishAndy]

Yeasts (particularly with ales) are arguably the most important contributors to beer flavour. After all, all you do is make wort. The yeast makes beer.

 

[VikeMan]

The short answer is that they make beers that feel, smell, taste, and sometimes look different.

Longer answer... Think about, say, a Saison, maybe Saison Dupont. That spicy/fruity "saison" character is coming from the yeast. Saison strains are ale strains. So are strains like US-05, which is known for its "clean" characteristics. Or think about the clove/banana of a hefeweizen. That's coming from the yeast, also an ale strain.

There are many characteristics of yeast strains which affect their performance and the final beer. Here are some of them:

- Relative degree of attenuation
- Flocculation tendency
- Ester production tendencies
- Ability (or not) to produce Phenols
- Degree of biotransformation of hop compounds
- Alcohol tolerance

 

[BrewMan13]

Think of yeast options like dog breeds. All ale yeast is saccharomyces cerevisiae, just like all dogs are canis lupus familiaris. Yet, not all dog breeds are the same, and not all yeasts are the same. The ones we use are the ones with beneficial brewing attributes, be it flavor, brewing performance etc.