So I'm a pretty big fan of white labs California ale yeast, and I've been using the same yeast for the past 5 months or so, and over that time span, it's probably been through 7 batches. I've been keeping pitching from the bottom of the bottle into starters every time, being pretty sterile, but not necessarily over the top. I'm seeing that a lot of people are saying not to reuse yeast past 4-5 batches and I'm wondering what the reasoning is behind this. Is it a contamination issue or a mutation issue? I'm guessing the latter. I'm starting to keg, so I'm going to be maintaining a mother culture until I start culturing it on agar. If my beer keeps on tasting good I see no reason to waste money (I'm poor). Anyways, if there's something I'm not getting feel free to shoot me down.
Limit to repitching yeast?
- Thread starter chimind
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tally350z
Well-Known Member
Genetic Drift or Contamination can be a factor. Sometimes it can be a noticable difference or not so much. As long as you are using proper sanitation you can probably get away with using that same yeast strain for a while.
Gab1788
Well-Known Member
I always do this for as long as I can. After a few generations (4 maybe 5) sometimes I get contamination. This is always a white coloured mould around the top of the karasen (sp?) I don't know what it is, I've posted pics of it on here in a thread I've started. If you're interested.
The one thing that I've noticed is that my beers finish a little higher FG but are super clear with later generations. It would be interesting to see what others think about this, but I think it might have to do with harvesting the cake and getting most of the yeast that floc early??
I'm not sure, but I pretty much make the same
Recipie every time, mash low for dryness (60 to 64) and when I'm using third or forth gen yeast (typically US05 but often others) I get super clear beer. I don't use any finning or clearing agents so it's not that.
Just something I've been thing about, have you noticed anything similar?
By the way, I just put the contamination issue down to running the gauntlet of exposing the yeast to the air too many times, you can only be lucky so many times. The beer still tastes fine though, so I don't know what it is. I just think its best to stop using it when it happens.
The one thing that I've noticed is that my beers finish a little higher FG but are super clear with later generations. It would be interesting to see what others think about this, but I think it might have to do with harvesting the cake and getting most of the yeast that floc early??
I'm not sure, but I pretty much make the same
Recipie every time, mash low for dryness (60 to 64) and when I'm using third or forth gen yeast (typically US05 but often others) I get super clear beer. I don't use any finning or clearing agents so it's not that.
Just something I've been thing about, have you noticed anything similar?
By the way, I just put the contamination issue down to running the gauntlet of exposing the yeast to the air too many times, you can only be lucky so many times. The beer still tastes fine though, so I don't know what it is. I just think its best to stop using it when it happens.
It depends upon many factors. The health of the yeast upon pitching, the part of the fermentation process when harvested, the health of the yeast upon harvesting, and how it was harvested. I have washed the same packet of US-05 around six times, I don't think I will bother with counting generations. I can understand the concerns of a commercial brewery with batch consistency, but for me it doesn't matter.
jwalker1140
Well-Known Member
I listened to an episode of The Sunday Session recently and they were talking about this (I don't remember which episode or who the guest was - seems like it was a "best of...." and the guest was someone from Anchor or Stone). Anyway, the guest said they set a limit of 10 generations, only because after that fermentation becomes less vigorous. Mutation and contamination, at least with a 10 gen. limit, aren't major concerns for them. The reason he doesn't look at mutation as a concern is because the occasional cell that does mutate gets overwhelmed by the sheer number of cells that don't.
I'll try to cite the source if/when I find it.
I'll try to cite the source if/when I find it.
tre9er
Well-Known Member
I've used the same chico for probably at least 6 or 7 batches. It was all I used for a while. I've split it up, used the whole cake, etc. So far no ill effects. I keep swearing I'm going to buy a $4 pack of US-05 and get rid of my harvested cakes, but.....
