Mixed yeasts

[bez]

Knowing very little about brewing could you use mixed yeasts or are they competitive. Reading on here apparently yeasts are very important in imparting flavour. Just wondering what effect a mixed bag would have.

 

[Argentum]

They could be competitive, in which case the aggressive yeast will stand in the end and the other yeast will be eradicated.

The best way to mix yeasts is to add the yeast from which you want to derive primary flavor characteristics (generally esters) up front, and add the second yeast at or immediately post peak fermentation for the first yeast. This works (for example) with Windsor up front and Nottingham following behind, wherein the flavor esters from the Windsor are departed into the forming beer, and then the comparatively esterless Nottingham (added second) eventually kicks in and takes the FG down well below where Windsor would have taken it, but the Nottingham can not take away the already produced Windsor esters. Windsor can reach peak fermentation within 24-36 hours, so once you see it start bubbling, add Nottingham 24 to no more than 36 hours later.

I once pitched Windsor and S-04 together right up front, and I'm somewhat convinced that the S-04 quickly wiped out the Windsor.

 

[Sadfield]

Pitching two yeasts is fine, and something some breweries do, Adnams being one of them. Usually one more flavoursome, the other more flocculant. One yeast may become dominant if the yeast is harvested and repitched into further brews.

 

[strange-steve]

There's a little trick Chris Colby discusses on Beer & Wine Journal (clicky) where he pitches a pack of neutral yeast (something like US-05) along with a more flavourful yeast strain to boost the pitch rate without altering the yeast character.