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the Grand Yeast Experiment

PostPosted: Sat Jul 05, 2008 10:31 pm
by Imakewort
I am conducting a yeast experiment, here is the question. Will a yeast in a fermenter do better if grown in a starter at room temp. or grown at controlled temps?
I am using a lager yeast wlp 830 starter size 4.5 liters. all grown from the same slant, same batch of starter solution, both on a stir plate, one starter was grown at room temp and the other was grown at 50 deg F. The beer is a Dortmunder export, A&B batch from the same 10 gallon batch, both aerated the same way for the same amount of time, both chilled to 45 deg F and the chilled decanted yeast added at the same time difference 20 minutes, allowed to rise to 50 deg. F in separate temp. controlled units with the same brand of temp. control units, with the temp probe used the same way in the same brand of freezer. Both batches of starter where chilled and decanted the same way for the same amount of time. This is as close for both batches as I can do. for space size I will follow up with the results after 6 days of fermentation.

PostPosted: Sat Jul 05, 2008 10:40 pm
by Imakewort
OK here is day 1 thru 6
day 1, little activity both temps went to about 49 deg F
day 2, A&B at 50 deg F, batch A starting to show signs of krausen, batch B no change, hereafter called just A&B
day 3, A forming a 1/2 inch Krausen, B very little change
day 4, A has 2 inch krausen, B 1/2 inch seems B is approx 12 hours behind A
day 5, no change
day 6, A's krausen is up to the neck of the carboy 4 + inches, B is now at 2 inches

I will follow up with a report every day from here on

PostPosted: Sun Jul 06, 2008 4:11 pm
by Imakewort
Day 7- no change, but not bubblying a lot. I need to point out that all of these observations are being done by my son Shawn as I am at work.

PostPosted: Sun Jul 06, 2008 7:24 pm
by aleguy
It seems to me that most lager yeast starters would do better if they were grown out at lager temperatures. However this is not necessarily the case. It would seem that your experiment is showing the intuitively obvious to be true for the strain you are using. It is the quality of the final product that matters though, so speed and vigorous fermentation don't always mean great beer.

PostPosted: Sun Jul 06, 2008 10:34 pm
by Imakewort
1 was grown at lager temps 50 deg f that is the fermentation temp of a lager. from what I know a yeast is at it's it peak at the 3rd generation, that is it likes the temp and environment the ones that do not are gone by then. I hope to prove that by growing your starter at the fermentation temp. you will have lots of yeast that like that temp. the number of petite mutants will be minimal. I can not say more as I do not want to give away which is which. For a in depth study See "Principles of Brewing science" 2nd edition by George fix, "Brewing lagers" by George Noonan, and The Brewers Handbook, I only know which is which. When I get home I will see how much they attenuate out at, taste for diacetyl do a rest if necessary then transfer, then lager for 6 weeks then the taste test. Mainly what I am doing is what the big boys do.

PostPosted: Wed Jul 16, 2008 10:16 am
by Imakewort
after 15 days A attenuated to 1.022, B attenuated to 1.020, raising the temp from 50 DEG F to 55 deg F

PostPosted: Sun Jul 20, 2008 1:11 pm
by Imakewort
now A&B down to 1.013 no sign of diacetyl transferring to lager tanks