Using yeast slurry

[bobtheUKbrewer2]

How many times is "safe" - I re-use twice then start over. At present I am using yeast grown from St Austell Proper job so my first use is really second use. By the way, I have confirmed that this is the yeast used for fermentation. I do not have kit to check the yeast. I put aside 10 bottles from my first use, and plan to harvest the yeast from one of them each time I brew. Great forum by the way.

 

[soccerdad]

I have always heard that slurry can be used 5 times. I have no idea how accurate that is or is it is just an "old brewers tale." For me that would be 10 uses in 5 generations and I just don't brew enough for that. I keep about 2 pints of slurry if and when I save. So each generation would give me 2 uses. I have also taken to shaking those starters rather than stirring them. Seems to work well.

 

[CascadesBrewer]

I don't think there is any hard limit and it will depend a bit on your process. I got many batches over about 1.5 years out of a single pack of WLP001 (probably 15 batches, a mix of 5 gal, 2.5 gal and 1 gal batches). I have gotten maybe 5 generations a couple times from other yeast. I never hit a point where I noticed issues with the yeast, I either just moved on to trying out a different strain or used up my last slurry into something like a high gravity beer or a heavily dry hopped beer that I did not want to harvest from.

If you have a stir plate, making over-built starters might be the safest way to keep a strain going longer term.

 

[bobtheUKbrewer2]

I assume that even new dried yeast has "some" bacteria in it, and there will be more (but not enough to cause problems) after the first fermentation. Plus there will be some yeast mutations. Commercially, I understand "perfect" yeast cells are selected and multiplied up. I think 3 uses will be my limit. Thanks all.

 

[odie]

unlimited uses until it goes south...sniff test is usually all you need.

the key is cleanliness and sanitation of your yeast harvesting process.