Just got myself an antique microscope and haemocytometer so I can count yeast cells and then stop blaming the yeast for messing up my brews from time to time
I've had WLP300 on a stir plate for a while and have counted the cells and reckon on 59M/ml @ 850ml = 50.15 Billion cells - that maths look ok?Chris White in 'Yeast' says a pitching rate of 0.5 to 0.75 Million cells/ml for Ales or Weiss per degree P is a good rate.
So at the lower end of that scale: 0.5 x 19,000 (19L of wort) x 12 (roughly 1.048)= 114 Billion cells needed.
He then goes on to say that yeast grown from slants with good aeration could use 50% less than the above figure, which was based on repitching anyway?
If so, then the ideal pitching rate could be 114 / 2 = 57 Billion cells, which is a little more than my 50 Billion - but close.
Can anyone please confirm or rubbish my calculations?
Or anyone who has experience of optimum pitching rates for Weiss, as the range of 0.5 to 0.75 leaves an enormous difference in yeast numbers.
Grateful for any knowledge I could acquire.