Just wondering how many of the Brewpub Brewers aerate their
yeast before pitching. If the Pub Brewer transferes yeast from one FV to
the new wort, are you getting the yeast out of anaerobic into aerobic stage or not.
We aerate the yeast on a new pitch. ie we reconstitute our dry yeast and let it grow for 2 days in a 6 degree Plato wort that is oxygenated, but we also inject O2 into our transfer hose through a small carb stone setup as we move the wort to the Fermenter. If we re-pitch then we pull the yeast off into sanitary 5 Gallon tanks and inject it into the Fermenter through the racking port with no aeration but again we injected O2 into the wort at transfer, normal time to start seeing active fermentation 2-3 hours in both cases.
Laughing Dog Brewing
I believe this may've been mentioned in a thread earlier, but in Germany some brewers are experimenting with aerating their yeast only in order to protect the antioxidants present in the wort. It's not in wide use, though.
We start every batch of yeats fresh from a petri dish and then transfer it to flasks. It is fully aerated by the time it hits the aerated wort. This is a labor intensive but a great way to do things. Perfect quality control on your yeast, no worries about infections and because of the lively state of the yeast we have a very low pitching rate.
Last edited by BelgianBrewer; 04-05-2008 at 12:36 AM.
That sounds great. Unfortunately it's not very common. Ignoring the needs of the yeast is a problem all over the brewing world. They are little organisms, and if they're happy, they do what they do best. I think that's the area of brewing that needs the most improvement in general.
I agree with the last comment, but would also add that some yeasts seem to work best a few generations after the culture, and result in more consistent beer. It is just possible that you would do better to repitch, but I agree only if you have good kit, and control things well. I would also feel happier having a little fat in the system. What happens if the worst does happen, and it fails to grow or you get an infection ? Unfortunately, it does happen even in the best run brewery.
Yes, unfortunately living with low level infections and fighting to keep them as low as possible is not uncommon in the brewing world.
I think ale yeast can pretty much be repitched for an eternity, if they're carefully managed. But that's not the case with lager yeast, since the most desirable ones don't get repitched (they end up in the lager tank).
I'm not sure about ale yeast but with lager yeast, it has been found that a mix of propogation yeast and repitched yeast is best.