In the past, I have been pretty critical about what I felt were dumbed down instructions issued by some of the yeast manufacturers. The idea that a single pack/vial is ideal for 5 gallons of wort, regardless of whether it's a 1.030 or a 1.060 wort, and regardless of the age of the yeast (from fresh right on up to 4 months (or 6 months), but not beyond) seemed dubious. But recently I conducted a study of viable yeast cell counts, using the Chico strain. I drew a small sample each day and counted viable cells using the methylene blue/hemocytometer method, and frankly I was somewhat surprised by the results. Here is a graph of the daily counts from day one through day 190... According to my data, the viable yeast count seems to be fairly steady at approximately 125B through day 180. At day 181 there's a slight drop off. It's minor, but I think I now understand how the expiration dates on yeast packages were derived. Of course, I would be remiss if I didn't point out that the blue/hemocytometer method isn't perfect, and therefore the data is inconclusive. Over the course of my study, I was fortunate to get access to a very powerful microscope at a local college. I'm not sure of its specs, but the model had a large number with an "X" at the end. Here's is what I saw when I zoomed in on individual yeast cells on selected days... Day 1: Day 180: Day 181: I'm not sure what to make of these observations, but I have a hunch that I may be retiring my stir plate and calculators soon. It really just may be as simple as reading the directions on a yeast package, which will free up some time for some base malt diastatic power deterioration calculations I've been meaning to get around to.
Interesting data points. I've been running my own data collection trails as well trying to minimize initial explosive blowoff (I'm referring to it as "eruptile distinction"). I've been playing around with dosages of ambian and/or valium to calm down the initial surge of fermentation. So far the data has been inconclusive as well but the actual beer has been amazing, from what I can remember. Thanks for the hustle.
I'm personally offended by the term "fixin' ". This is a colloquial term, primarily used in the Southern states. Yeast from CA (Chico) observed in PA (Vikeman) would never utter such nonsense. Also not buying any lame excuse like the fine-focus knob had stripped gears. Hoping your diastatic analysis can be performed in a manner less regionally-biased . . . and you call yourself a Meyvn, smh . . . MOD alert ^ ^ ^
Since getting into brewing even more and going from a 5 gallon batch or two a year to one a month, last summer, I have been using 1 packed of liquid yeast for 5 gallons regardless of what Brewcipher says. Never had a problem making FG or better according to brewcipher. Only time I used more packages was when I had a brew with and SG of over 1.11. I never understood why a package would be sold if it wasn't OK for one batch, other then money of course.
