Using Multiple Yeast Strains
Can you use more than one type of yeast to ferment your wort? Yes! Brewer’s yeast live harmonious lives. They won’t compete with other yeast and destroy them, so feel free to combine more than one type of yeast in the same vessel if you’re looking for a “secret sauce.”
Using multiple yeasts can provide a unique, signature flavor to your beers that no one else can replicate with a single yeast strain (and they probably won’t be able to identify the correct combination of yeasts unless you tell them what you used). You can create more complex and interesting yeast profiles using multiple yeast strains than one.
There are a few things you’ll want to remember before using multiple yeasts:
First, make sure all of the yeast strains you plan to use will ferment at the temperature you’ll be keeping your wort at. Any good packaged yeast will note its optimum fermentation temperature range. Using an ale yeast along with a lager yeast might work, but you might also find that one or the other did nothing at all.
You’ll also want to be careful not to overpitch (yes, it’s possible to use too much yeast). If you use too much yeast, the beer will have a yeast character, sometimes referred to as yeast bite. In a 5 gallon batch, you’re safe to use twice as much yeast as you normally would. But, if you use three or more types of yeast, you’ll probably want to cut back on each strain by a bit.
Finally, pitch the yeast early rather than in drawn-out steps. The bulk of the flavor profile from yeast will be developed within the first 12 to 36 hours of fermentation, so you don’t want to wait too long to add your second (or third) yeast to the wort. There’s also less risk of infection if you pitch them all at once instead of exposing your wort shortly after fermentation begins.