What’s the shelf life of trub yeast?

Share your experiences of using brewing yeast.
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Top Cat
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What’s the shelf life of trub yeast?

Post by Top Cat » Thu Sep 27, 2018 2:38 pm

Good afternoon guys.
A few weeks ago I had a go at brewing a beer that I’ve been drinking for a few years now down in Somerset from Cheddar ales called Potholer. I’ve visited the brewery a few times in the past to collect a small keg of draft for weekend drinking, imo it’s a beautiful well balanced golden ale. The bottle version contains live yeast, so seeking the advice of the head brewer who confirmed it was primary yeast, I purchased a few bottles to cultivate the yeast. Up to date now! The fermentation of the brew went very well, stared at 18c dropped from 1044 to 1011 in five days, rested it for another 5 days, then refrigerated to 1c for 2 more days before racking. When transferring to bottles and cornie, I noticed the beer was clearer than normal, and a small sample tasted confirmed the beer when matured should be a good ‘un’. The yeast had fallen to the bottom of the fermentation vessel like lead, it was very compact. I don’t normally take yeast from here and usually use it from a bottle a do a starter, but I was so impressed with the performance I collected about 100ml in a mustard jar and put it in the fridge, hopefully to use without the need for a starter.
How long will the yeast keep before it is not viable to use?
Thanks in anticipation.

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gr_baker
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Re: What’s the shelf life of trub yeast?

Post by gr_baker » Thu Sep 27, 2018 3:12 pm

I've kept this kind of yeast for a couple of months in the fridge before using. I suspect that if you left it a long time you might have to make up a starter to get enough viable yeast. I've certainly made starters from yeast samples kept in the fridge for couple of years

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Kev888
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Re: What’s the shelf life of trub yeast?

Post by Kev888 » Thu Sep 27, 2018 9:49 pm

There isn't really a fixed shelf life as such, there are just fewer viable cells as time goes on. When this number falls below the rate you want to pitch, a starter is required to build them up again - within reason, anyway. So it depends on how many you collected and how many you need, as well as the time (and of course on how well you avoided contamination/infection etc).

There are ways you can guess how many cells you started with and also estimate the likely drop in viability over time; calculators such as the Mr. Malty one can help (free online from a desktop computer, I believe the app is charged for). They're all quite rough estimates without lab facilities to really look at the yeast, but will give you an idea.
Kev

Top Cat
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Re: What’s the shelf life of trub yeast?

Post by Top Cat » Sat Sep 29, 2018 4:29 pm

Thanks for your help guys.
I generally brew 23/25 ltrs once a month, with fermentation and rest being about 2 weeks, so effectively the yeast is stored for approx 2 weeks before pitching if I choose to go that way. I took Kevs advice after going on Mr Malty’s website and down loaded the app. For the price of a pint the calculator will be very useful, it’s surprising how the viability decreases within a relatively short period of time. I now have an idea of how much to collect and when to use a starter.

greenwood
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Re: What’s the shelf life of trub yeast?

Post by greenwood » Sat Nov 17, 2018 7:51 pm

Top Cat wrote:Good afternoon guys.
A few weeks ago I had a go at brewing a beer that I’ve been drinking for a few years now down in Somerset from Cheddar ales called Potholer. I’ve visited the brewery a few times in the past to collect a small keg of draft for weekend drinking, imo it’s a beautiful well balanced golden ale. The bottle version contains live yeast, so seeking the advice of the head brewer who confirmed it was primary yeast, I purchased a few bottles to cultivate the yeast. Up to date now! The fermentation of the brew went very well, stared at 18c dropped from 1044 to 1011 in five days, rested it for another 5 days, then refrigerated to 1c for 2 more days before racking. When transferring to bottles and cornie, I noticed the beer was clearer than normal, and a small sample tasted confirmed the beer when matured should be a good ‘un’. The yeast had fallen to the bottom of the fermentation vessel like lead, it was very compact. I don’t normally take yeast from here and usually use it from a bottle a do a starter, but I was so impressed with the performance I collected about 100ml in a mustard jar and put it in the fridge, hopefully to use without the need for a starter.
How long will the yeast keep before it is not viable to use?
Thanks in anticipation.
I don’t think they use their own yeast as there’s no mention in website . I wouldn’t be surprised if it’s SO4. Crystal clear and little to add to flavour. Very interesting as I live close by .


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Rhodesy
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Re: What’s the shelf life of trub yeast?

Post by Rhodesy » Sun Nov 18, 2018 11:28 am

I am going to make use of collected yeast from my fermentasaurus with a straigh repitch using the slurry. I have it in the fridge in a 1L sodastream bottle it was collected directly in. I will be making use of the MrMalty guidance for amounts which hopefully works to plan.

greenwood
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Re: What’s the shelf life of trub yeast?

Post by greenwood » Sun Nov 18, 2018 4:23 pm

Topcat .. just walked in my man cave and there is a bottle of potholer on top shelf staring at me! Only one think for it ! Down the neck and conical flask out !! ( is that 2 things??)You inspired me !


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