frankvw
Well-Known Member
Hi, everyone,
I'm trying to propagate yeast. I made a medium-gravity wort (1045) from liquid malt extract, added 500ml (= two cups in Church of England measurements) of it to a lab flask, aerated it, pitched my yeast sample, and waited for things to happen. (Needless to say I have been anal about keeping everything as sterile as possible.)
The yeast pretty much started fermenting the wort immediately (judged by bubbles coming out of the airlock) and has now settled again. The volume of yeast at the bottom of the flask is exactly the same as I started with. The yeast looks healthy and there are no funny smells, but the volume of yeast has not increased.
I poured off the beer, added a fresh quantity of well-aerated wort, and exactly the same thing happened.
What could cause this? The only thing I can think of is lack of nutrients for the yeast to work with, but in theory the wort should contain enough nutrients. Could it be a lack of nitrogen in the LME-based wort? Any other possible reason?
All thoughts appreciated. Cheers!
// FvW
I'm trying to propagate yeast. I made a medium-gravity wort (1045) from liquid malt extract, added 500ml (= two cups in Church of England measurements) of it to a lab flask, aerated it, pitched my yeast sample, and waited for things to happen. (Needless to say I have been anal about keeping everything as sterile as possible.)
The yeast pretty much started fermenting the wort immediately (judged by bubbles coming out of the airlock) and has now settled again. The volume of yeast at the bottom of the flask is exactly the same as I started with. The yeast looks healthy and there are no funny smells, but the volume of yeast has not increased.
I poured off the beer, added a fresh quantity of well-aerated wort, and exactly the same thing happened.
What could cause this? The only thing I can think of is lack of nutrients for the yeast to work with, but in theory the wort should contain enough nutrients. Could it be a lack of nitrogen in the LME-based wort? Any other possible reason?
All thoughts appreciated. Cheers!
// FvW