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How long can a yeast starter last?

I have two yeast starters that will be going on four weeks and I have not had time to brew at all. Next week I’m going to Las Vegas for a week and I will not be able to brew beer until March 26th. Will the yeast starters be okay? I mean they’re in the refrigerator but I’m wondering if some of the yeast will start to die. Should I make some more wort and maybe revitalise them? I decanted the old wort last week.



Leave them under the beer cap, refrigerated… sealed… I’ve been using the foam stoppers for a while now and am happy with my results… No vacuum created that either pulls from an airlock, or pulling Saran Wrap into the beer cap… Sneezles61

Can always make some starter wort before u use it…just decant and pitch into that :slightly_smiling_face:

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I have already decanted all but about a quarter inch of wort. I have both jars sealed with tinfoil.

I was thinking about making more starter wort the day before I brew but right now I am just concerned with the viability of the yeast. Now I wish I would have kept the Wort on top of the yeast

If you haven’t left yet, pour some finished beer on it, heck give yourself at least an inch cap… Cheap insurance… Yes, then when you are about to brew, a few days ahead, make a starter, decant the beer cap and wake it up. I’ve been doing this with yeast for a long time now as well as others on here do. My way has changed up a bit… I now am pulling yeast, skimming at high krausen from the fermenter, then saving just as we are talking… Sneezles61

Well that makes sense. If I pour finished beer on it then there’s nothing to react with. Is that what you are saying? Wonder if I could just dispense a little beer out of a tap and let it come out of saturation and then pour that on top of the yeast?

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Personally, I’d be fine with 1/4" wort cap. The real issue is viability over time. A four week old starter loses viability at the same rate as slurry or package yeast. The difference is that with a good clean starter you can produce a higher density slurry with maybe 2-3B cells per ml.

I use a yeast calculator like brewersfriend, plug in the dates for a package yeast to get % viability then apply that percentage to my slurry or aged starter.

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I rarely brew often enough or similar enough styles to reuse saved yeast straight up. If its more than a month old the viability has dropped off significantly. The majority of the time I find myself doing the shaken not stirred yeast starter overnight as a “vitality” starter. By seeing a nice vigorous response, and pitching at high krauesen you can be sure to have a decent fermentation.
@brentconn when you say yeast starter do you mean saved slurry?

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I’m on an 8 generation yeast… Perhaps, not quite the same as when I skim from a high krausen yeast… Still the same vial I started quite some time ago… Sneezles61

The beauty of it is that the yeast will tend to stabilize. Not exactly the same as the vial you bought, but it’ll adapt to your system and environment, and should stop changing. There’s a brewery in the mitten state that’s on about their 900th pitch of their house yeast. I’m sure they’re acid washing and doing all the other steps, but I think us homebrewers don’t push the limits of our yeast enough…

I’ve never been able to make it past about 4 generations because of lengthy power outages… I did do a SNSYS tonight with a 3rd generation slurry of Belgian Saison(Wyeast 3724).
I like the convenience of a yeast bank, if not the cost savings, which over time can be considerable.

I don’t follow… Being a home brewer, a yeast bank? Are we talking about buying yeast at your LHBS or are you more advanced than that? :neutral_face: Sneezles61

Hah, no, not advanced at all. I just meant a collection of yeast slurries in the fridge…my “yeast bank”.


My bank is back up to about 12 qt jars of slurry. The oldest of which may be close to a year by now. I’ve been planning to brew a marzen since early Feb with bavarian lager yeast slurry from a dec 10 last pitch. If I’d brewed early to mid february I could’ve split that slurry and brewed 11 gallons. Now I think I’m looking at using it all for 5.5 gals so trying to decide if I should do the marzen or maybe something else to step up for 11 gals of marzen…decisions decisions…

So I wound up just pouring some beer from a tap and letting it settle then I poured on top of the yeast. When I get ready to brew a week from this coming Monday, I will just make some more DME and let it Revitalize or propagate

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