Hybrid Yeast?

[MattK]

I've noticed that JZ's pitching rate calculator (and several others) reference hybrid yeast strains as a separate type of yeast. I haven't had much luck determining exactly what this is.

Does this refer to specific strains of yeast, or perhaps when doing a lager yeast at ale temps? I was thinking that it might be for strains one would use in a kolsch or altbier, but I can't seem to find anything concrete. If this is specific strains, can anyone point me to a good list so I can ensure I use the right data for starter growth?

Can anyone clear this up for me?

Cheers!

[peas_and_corn]

Basically it's yeast that exhibits behaviours that are associated with both ale and lager yeasts. Cal Common yeast is considered to be a hybrid yeast because it's very clean ester-wise like a lager but its optimum fermentation temperature ranger is more like that of an ale yeast.

[PorkSlapper]

Yes, Cal common, Kolsch and Altbier yeast strains are in the catagory of hybrid Mr. Malty's pitching rate calculator.

[brewinhard]

what if you are fermenting with a hefe strain at low temps (60-62)? would that be considered at a hybrid pitching rate or is it referring to ester production control?

[dstar26t]

I would generalize hybrid as anything you plan to ferment around 60F. You are pitching more yeast because it won't grow as fast at that temp. Scotch ales, Alt, Kolsch, etc.

Hefeweizen yeast can be very dynamic depending on many factors. I like to pitch like an ale (.75 Million/mL/ºP), oxygenate like a hybrid and start at 60F for 24 hrs and then run it at 62F. For Scotch Ales I like to underpitch (.5 Million cells/mL/ºP) and start them at 58ºF, then warm to 60ºF. Some good esters are made with that combo.