re using yeast

Share your experiences of using brewing yeast.
guypettigrew
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re using yeast

Post by guypettigrew » Thu Apr 29, 2021 8:05 am

This Saturday's brew will use a Proper Job yeast. This will be the fourth time it's been used since harvesting it from some bottles a couple of months ago.

The yeast is collected by scooping out about 1/2 litre of fermenting beer from the top of the FV 24-36 hours after pitching and when there is a good strong krausen. It's stored in the 'fridge, where a thin layer of yeast settles out, until needed. It's then woken up in 1 litre of malt extract at about 1.040.

How many times do you re-use your yeast? I've always thought 3 or 4 times is enough, given my extremely basic yeast collecting technique and facilities. Getting an infection and losing a batch of beer is not worth the risk.

How often do others renew their yeast?

Guy

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vacant
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Re: re using yeast

Post by vacant » Thu Apr 29, 2021 8:46 am

I have scooped and stored PJ yeast but since a bottle is now only £1.49 I haven't bothered recently. I have a litre on a stir plate since yesterday. I keep a container of wort from each brew frozen for starters which saves a bit on DME.

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Re: re using yeast

Post by Meatymc » Thu Apr 29, 2021 10:17 am

guypettigrew wrote:
Thu Apr 29, 2021 8:05 am
The yeast is collected by scooping out about 1/2 litre of fermenting beer from the top of the FV 24-36 hours after pitching and when there is a good strong krausen. It's stored in the 'fridge, where a thin layer of yeast settles out, until needed. It's then woken up in 1 litre of malt extract at about 1.040.

Exactly same process (followed IPA's advice on process) although I use 150g DME in 1800ml which boils down to 1500ml going into the fermenter. And total of 4 brews - 1st scavenged and 3 harvested. Can't say there's any deep thought process involved - just a good excuse to buy more PJ and start again!

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Eric
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Re: re using yeast

Post by Eric » Thu Apr 29, 2021 11:56 am

There is probably some degree of dependency upon the specific strain of yeast.

I've found significant variation in performance, with some yeasts declining over time while others can thrive to become prolific reproducers.

One strain has lasted 4 years and pitched over 30 times.

I mostly top-crop and repitch without a starter.
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Re: re using yeast

Post by Jocky » Thu Apr 29, 2021 1:14 pm

I tend to make an extra large starter and then put some of it into a sterilised 120ml jar I have and then regrow it when I need it. That way I don't get too much drift in performance and don't have to keep too much yeast either.

The only time I reuse is when I'm making a big beer and then I tend to make a normal strength beer first and then scoop out yeast in the bottom of the fermenter into some larger (500ml ish) sterilised jars so I can clean up the fermenter.
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Re: re using yeast

Post by FUBAR » Thu Apr 29, 2021 3:12 pm

I have some wyeast West Yorkshire that had been top cropped and straight pitched into another brew ( a week after harvesting ) 4 times . The last use I was to late to crop and the yeast had sunk into the beer , so I harvested some slurry and stored it in the fridge for just over 3 weeks . Fed it a bit of wort on Monday afternoon and it picked up rapidly so a 1ltr starter was made the same day , it will be pitched into tomorrows Bitter brew and I intend on carrying on top cropping again from this for as long as possible .
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guypettigrew
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Re: re using yeast

Post by guypettigrew » Sun May 02, 2021 6:06 pm

Thanks all. Blindingly obvious when you think about it. As Vacant and Meatymc said, at about £1.50 a bottle for PJ just buy some more. The yeast is, in effect, 'free'!

Guy

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Re: re using yeast

Post by MashBag » Mon May 03, 2021 8:26 am

Eric wrote:
Thu Apr 29, 2021 11:56 am

I mostly top-crop and repitch without a starter.
Agree. And freeze until required!

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Re: re using yeast

Post by guypettigrew » Mon May 03, 2021 2:06 pm

MashBag wrote:
Mon May 03, 2021 8:26 am
Agree. And freeze until required!
Really not sure I believe you! If freezing liquid yeast worked then it would be common practice. Plus, even if it did work, it's very hard to believe you can get it to ferment a 25 litre batch without building a starter.

Guy

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Re: re using yeast

Post by MashBag » Mon May 03, 2021 3:14 pm

Okay.
You are never going to believe I have just removed the top off the bottle dropped it in frozen. Fermenting well in 24 hours.

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Eric
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Re: re using yeast

Post by Eric » Mon May 03, 2021 4:34 pm

For clarification, freezing yeast has not been part of the procedure I adopt.
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Re: re using yeast

Post by MashBag » Mon May 03, 2021 6:10 pm

Eric wrote:
Thu Apr 29, 2021 11:56 am
....
I mostly top-crop and repitch without a starter.
Do you feed it while under refrigeration?

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Re: re using yeast

Post by Eric » Mon May 03, 2021 6:48 pm

No.

For several years, most of my brews have used top fermenting yeasts used by British commercial breweries. For ~3 days the fermentation is roused and when activity begins to decline and the krausen compacts and thicken, the yeast is skimmed to leave a thin covering. It is then allowed to cool and is usually casked a week from pitching.

The cropping will fill a pressure cooked recycled beetroot jar of around a half a litre. In the fridge the yeast will compact down with an inch or so of solid yeast covered by green beer and topped with krausen. Any attempt to feed this will result in an unholy mess with a very short time.
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Re: re using yeast

Post by MashBag » Tue May 04, 2021 6:39 am

Thanks for the detail. How long does it stay viable?

McMullan

Re: re using yeast

Post by McMullan » Tue May 04, 2021 8:48 am

MashBag wrote:
Tue May 04, 2021 6:39 am
Thanks for the detail. How long does it stay viable?
It can remain viable for years, even at room temperature; but, if the aim is to repitch top-notch yeast without making a starter, it’s best used within a few days. If kept cool and mixed/swirled occasionally (to distribute scarce resources as evenly as possible) within several days. The benefit is you get to pitch the best yeast possible with the highest level of viability. Fermentation well under way within a few to several hours, not 24, and finish within 3 days or so. Although I don’t believe it’s possible for home brewers to over pitch healthy yeast, I suspect you might be over pitching dead yeast cells therefore risking off flavours associated with yeast autolysis. Without conditioning cells for a freeze-thaw cycle the viability of your slurry is probably <25% (vs >99% fresh unfrozen top-cropped slurry). I can only imagine you’re bottling and freezing enough yeast so that 25% scrapes fermentation through. To be honest, I don’t think your practice is bad, I think it’s terrible. Can anyone on the forum review your beers? I’m pretty confident you could make noticeable improvements by adopting a better practice.

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