So I have an IPA fermenting now with 1056 and I plan on attempting my first go at top cropping. Seems like a pretty straightforward process (skim the protein layer off first 12-24 hours into primary, wait another 12-24 hours and harvest the yeasty kreusen into a sanitized jar). My main question is how do I know how much yeast I am harvesting? Is there any way to determine some kind of cell count without using a microscope to know how large of a starter I need to make from this top cropped yeast? Or is it generally a home brewer's rule of thumb that as long as you top crop as much viable yeast as possible and make a starter with it between 1-2 liters before repitching it, everything will be just fine?
I'm sure Jamil Z and Chris White could give you a pretty clear idea of how much yeast you need. How do they break it down in their book, by mL? They say that one of the old WL tubes holds 10mL? They give you about the size of a large marble in there and that's supposed to be 100b cells. I've just taken multiple spoonfuls of yeast off the top and pulled most of the krausen ring off the top of my bucket before. You can be pretty aggressive with this process and the yeast will perform flawlessly in the next session ale--assuming that your first batch is healthy yeast.
yeah there is a rule of thumb pro-brewers use, but off the top of my head, can't think of it now. If I'm waiting more than a week, then i'll make a starter, if I'm going basically direct into a new brew, I wouldn't make a starter. Since I brew at most frequent, 2-week intervals, all my top crop has been from a starter.
I'm new to top-cropping, too. Interested to hear your results when you have them. As for guidelines, I started here: http://www.wyeastlab.com/com-yeast-harvest.cfm Has some pretty good info and even some visual aids. Good luck.
I've reviewed this link a couple of times and while a little helpful it's ambiguous. Maybe that's the nature of counting yeast cells, but you have to make a lot of density assumptions to reach a conclusion . . . then they say it will vary by strains. Not dissing the tech advice, just looking for more details. I've measured the volume of the yeast solids in a WL vial, it's about 18ml. Assuming 100B per vial this yields 5.5B cells/ml. Of course this is new and fresh yeast. I recently top-cropped (actually collected blow-off in a sanitized jar) and ended up with just over 100ml of yeast solids. Pretty sure I don't have 550B cells of yeast. I believe in a 5 gallon batch the theoretical limit is around 600B. For the OP: my technique is to estimate 2B cells per ml of yeast slurry that has been top-cropped, or grew in a starter. I can give no scientific basis for this number, but for starters it seems to follow the predictions found by running a yeast calculator. This has produced pretty consistent results for me and if any brewer has more complete data I'm all ears. I would not make the assumption you stated in your last sentence . . . rather try and work with an estimate of yeast count (realizing this may take some trail and error).
1056 is not the best top crop yeast. You like to have thick creamy layer of bobbling active yeast, it's not the case of 1056. The desire mechanical property if the yeast to be harvest is not there like this video. Good toppers : 3068, wlp029, wlp300, 3711, 3944 and many more will give you long time window to skim active healthy yeast. 1056 is a natural easy bottom crop. 3944 3944 3944 3944 3944 crop crop crop
