Just got back from Munich, Germany. We toured 2 breweries, Spaten and Hofbrau.
The folks at Hofbrau harvest their yeast no less than 3 times after the primary fermentation.
I always harvested my yeast after the ferment, going as many as 7 generations. Each successive generation would improve in quality. And there was absolutely zero lag time after pitching!
What is the thinking here on the subject of harvesting yeast for use in future brews?
The most I have gone was 25 generations of a lager yeast. I gave up just to try something different. I think it was something like 2 years of using the one lager yeast on all of my lagers - I would have to check my notes, but I think it was WLP830 or 838.
I went over 15 generations with WY 1056 and WY 2206 a couple of years ago. Now I typically use a particular yeast around 5 generations because just like ynotbrusum, I like trying different strains.
I think I read on Ron Pattinson’s blog about a brewery who reused the same yeast for decades.
The Norwegian brewery Kinn are at something between 100 and 200 generations of top harvesting their English ale yeast. In my opinion they make stellar beer. They are using Wyeast 1318. They also do open fermentation. I don’t brew often enough to do much reuse, but I did it a few times with Bry-97, and the beer came out just as good as with a fresh pitch. I did not wash it or anything. Just scooped up what could have been a quarter of the slurry. Took off fast as I recall.
But don’t fall into the trap of thinking what commercial breweries do is what homebrewers should also do.
It can be a trap, but I’m not going to say it’s always a trap. What commercial brewers do, homebrewers can do. With limitations. Sometimes the scale means it’s not possible, or that it needs to be heavily modified. Often it’s no longer worth it. But there are good ideas that you can learn from. You can reuse yeast for a while and you’ll probably get better results than from first generation yeast that was grown in lab wort. When you get to the point that you have to start acid washing it, it’s really not worth it when you can start over for $8.
There is a possibility of genetic drift, also, but I didn’t encounter that in the lager serially re-pitching (that I could tell from taste or aroma). Perhaps I just got lucky. Also, I was usually racking from primary, harvesting and re-pitching on the same day, so I brewed many similar styles in succession with large, healthy re-pitches. Again, keeping yeast in a short dormancy helps things out. This is just one person’s experience and YMMV, as always.
I would typically harvest up thru the 8th generation. We always did a single primary ferment, then would collect the yeast from the bottom of the fermenter and store it in a glass jug under sterile wort, typically at 35-36 degrees F. Time in storage was 2 to 4 weeks.
With each new brew, the yeast would literally explode from the flask after being “woke up”, sometimes climbing outside of the container and going onto the countertop.
It not only worked great with zero lag time, it also tasted better and saved us some $$$.
Harvey’s. The same yeast has been in use for about 50 years. Top Cropping is used.
Yeah, youu need to look at particular techniques and assess the applicability to how you Brew. Some are worth imitating, others arent
Nearly all brewers use the same yeast strain for decades, or centuries. But not many big commercial brewers who actually harvest the yeast from a previous ferment to use in a succeeding brew.