Been home brewing for a few years now, but I am going to attempt to harvest and recycle my yeast for the first time. I have made starters before, but can someone give me a basic step by step to harvest the yeast? Is it as simple as: harvest some of the yeast cake from a previous batch, throw in an erlynmeyer with some yeast nutrient and create a starter? If so, how much of the yeast cake, and how many times do you need to repeat the process to get it done? TIA.
You will want to google "Yeast Washing Illustrated." There is a very detailed write up on another forum with pictures at each step of the process. After you have washed your yeast, you should end up with a pretty clean slurry. If you have the ability to measure the slurry in mL, you can use Mr. Malty's online yeast calculator to prepare a proper starter for your next batch of beer.
A lot of people seem to be opting for overbuilding their starters these days, rather than harvesting yeast from the fermenter. I like the sound of that idea a bit better, myself, since you have a much better idea of your cell count and it's simpler from a sanitation perspective. You have to think of it before brewing, though, so that won't help you if you're already fermenting your batch.
Here's another slightly different technique on yeast washing with a good video. Either method should give good results. Not Mentioned: How much "yeast" do you have when finished? I estimate 2B cells per ml of washed yeast. I.E, if you recover 80ml from a gallon of wash I use 160B as the starting point, then adjust for time in storage. I can give no reference for this figure other than personal experience . . . but you have to start somewhere. As mentioned, building an oversized starter is another good technique. If you need 200B, then make 250 - 300B in the starter and pour off the excess for the future. Advantages: easier (IMO), more sanitary, and yeast do not suffer the stress of fermentation. In theory, the yeast can be perpetrated forever. Also recommend use of a yeast calculator to determine how to reach your goal. Be advised, yeast growth may not be linear . . . 1L + 1L ≠ 2L. A couple of good online ones (and free) are Brewcipher, yeastcalculator.com, and Brewers Friend. I find the Mr Malty calculator to be lacking due to no step-menu.
Yeast washing does no harm (if done correctly) but the fact is that if your overall brewing practices are good, yeast washing is a totally unnecessary activity. I've experimented quite a bit with repitiching both unwashed and washed yeast, and there wee no differences in the end results. For the last 35+ years, I've been harvesting the slurry from my primary and simply saving it (in some of it's own beer) in a foil covered flask or jar in the fridge. I've also gone as far as repitching the slurry from successive batches through well over a dozen generations, with no ill effects or off flavors whatsoever. Again, washing the yeast is fine if it gives you peace of mind.... but the bottom line is that you really don't need to do it.
Thanks for the video....And all this time I've been pronouncing it "trub" like rhymes with bathtub.... not "troob" lol. Still, looks like a pretty involved process but I guess it makes sense if one is doing a substantial amount of brewing.
Trub has an umlaut, I post from my phone and I don't know to bring up crazy symbols other than emoji. But yeah I've seen a lot of home brewing videos with Americans pronouncing it "trub" like "sub", always makes me cringe.
On another note, I've noticed many posts on this forum referring to kettle break material as trub. I think the original Deutsch term trub meant the yeast cake, or lees? Or maybe it refers to the break material, also? Paging @herrburgess...
Trüb in general just means cloudy (adj) or cloudy material (n). So it is used to refer to kettle break as well as the other preciptates that settle out with the yeast when fermentation is done.
