Author Topic: Viability of WLP830  (Read 343 times)

Offline waltsmalt

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Viability of WLP830
« on: August 03, 2020, 10:18:34 PM »
Back in March, I picked up two packs of WLP830 - German Lager Yeast to brew a lager.  Well, one thing led to another and I didn't get around to it.  Was hoping to finally brew it this weekend.  Plan was to do a starter and probably step it up to grow the yeast needed for a 1.050-ish lager.  When I went to a few calculators it said 0% viability based on a manufacturer date of 1/15/2020. 

Thoughts on whether or not I should just scrap this yeast, or just go buy fresh yeast.  I don't want to spend the effort with the starters and brewing, if I don't have enough viable yeast in the end. 

Offline denny

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Re: Viability of WLP830
« Reply #1 on: August 03, 2020, 10:26:26 PM »
I made a tripel once after making a starter with a 3 1/2 year old smackpack of WY3787.  The beer turned out fine.
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Offline hopfenundmalz

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Re: Viability of WLP830
« Reply #2 on: August 03, 2020, 10:54:50 PM »
Make a small starter, use both packs, bump it up again before brew day.
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Offline GrumpyWally

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Re: Viability of WLP830
« Reply #3 on: August 04, 2020, 06:35:10 PM »
I once chewed out a White Labs employee for selling me expired yeast. He claimed that the 0% viability number used by many calculators is out-dated. I've been using the table at the bottom of this page in my calculations: https://www.whitelabs.com/news/purepitch-shelf-life

Offline Saccharomyces

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Re: Viability of WLP830
« Reply #4 on: August 04, 2020, 10:26:37 PM »
I have started cultures off of slants that were several years old.  The trick when starting an old culture is to start with a reduced amount of medium (wort) at a reduced gravity.  In this case, I would pitch one package into 250ml of 1.020 wort.  If one uses the metric system, making 1.020 wort is child's play because a 1.020 starter is a 5% w/v solution.   We can make a 250ml 5% w/v solution by mixing 12.5 grams of spray malt into 250ml of water.  At 5%, the sugar will not do much in the way to increase the volume of the solution because it breaks down into molecules that take up much less space.  You can do a 250ml SNS starter in a 1L bottle or even a 1L Erlenmeyer flask if you use a sanitized solid stopper during the shake (you need to hold on to the stopper or it and the wort will go flying).  I would wait for 12 and 18 hours before stepping it up it up to quart using 750ml of 1.040 wort (1.040 is a 10% w/v solution; therefore, you will 750 * 0.1 = 75 grams of spray malt to make the step up starter wort), what you want to do because the first-level starter is bound to have lot of dead cells is to only decant the supernatant (the liquid that is above the solids on the bottom of the container) into the next step wort. Whatever you do, do not allow the first level starter to ferment out because it will be much more difficult to separate the viable cells from the non-viable cells and you only want to pitch viable cells into the starter you plan to pitch when there are that many dead cells.  I would use SNS for both steps.  Remember, a huge part of SNS is pitching everything at high krausen; however, in the case of the first-level starter, you only want the cells that are in suspension.  If you do it right, the only thing that will be on the bottom of your second-level starter well be break.

By the way, throw your yeast calculator away.  Yeast cultures are like nuclear weapons because close is good enough.  Yeast cells grow exponentially, not linearly, as many home brewers believe.  The yeast biomass cell doubles every 90 minutes; therefore, the difference between 1L starter and a 2L starter is one replication period the starter is pitched.  What is more important is pitching healthy cells at the right time.  Another thing is that a lot of home brewers are afraid to do is to pitch starter wort believing that it will make their beer taste bad.  That only occurs when one uses a stir plate due to the stress a stir plate places on the cells.  If one smells an SNS starter at high krausen, it smells a lot like bread.  That is because the cells have not experienced the stress that they experience on a stir plate.  Stressed cells are not healthy cells.
« Last Edit: August 04, 2020, 10:30:08 PM by Saccharomyces »

Offline denny

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Re: Viability of WLP830
« Reply #5 on: August 05, 2020, 02:24:32 PM »

By the way, throw your yeast calculator away.  Yeast cultures are like nuclear weapons because close is good enough.  Yeast cells grow exponentially, not linearly, as many home brewers believe.  The yeast biomass cell doubles every 90 minutes; therefore, the difference between 1L starter and a 2L starter is one replication period the starter is pitched.  What is more important is pitching healthy cells at the right time.  Another thing is that a lot of home brewers are afraid to do is to pitch starter wort believing that it will make their beer taste bad.  That only occurs when one uses a stir plate due to the stress a stir plate places on the cells.  If one smells an SNS starter at high krausen, it smells a lot like bread.  That is because the cells have not experienced the stress that they experience on a stir plate.  Stressed cells are not healthy cells.

Thisnism exactly what I discovered through experience with the method.  The yeast seems to be much healthier without a stir plate.
Life begins at 60.....1.060, that is!

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Offline tommymorris

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Re: Viability of WLP830
« Reply #6 on: August 05, 2020, 04:18:53 PM »
I once chewed out a White Labs employee for selling me expired yeast. He claimed that the 0% viability number used by many calculators is out-dated. I've been using the table at the bottom of this page in my calculations: https://www.whitelabs.com/news/purepitch-shelf-life
That’s good information. 71% viable after 6 months is pretty good.

Offline joeinma

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Re: Viability of WLP830
« Reply #7 on: August 20, 2020, 04:59:48 PM »
Kind of late to the discussion, but on the White Labs website they state that their PurePitch packages have a much longer viability then what yeast calculators say, based on various internal tests.  They state that they only have a 3.2% loss in viability per month.  So if their data is factual, then your yeast would have been somewhere in the 60% viability range.
https://www.whitelabs.com/news/purepitch-shelf-life

Offline dmtaylor

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Re: Viability of WLP830
« Reply #8 on: August 20, 2020, 05:08:32 PM »
I have used a lot of old yeast over the years.  Based on experience, my own cutoff for minimizing risk of contamination due to low health yeast is about 8-9 months from manufacture.  So if something was made in January, I think it's still worth trying to make a starter with it until at least September, maybe October.  Beyond that point, I shall not even attempt to resurrect a liquid yeast any older than that.  Sometimes it has turned out fine.  Other times I have experienced some wild fermentations.  While I have little doubt that another brewer with impeccable cleaning and sanitization techniques would be able to make effective use of liquid yeasts older than that... that brewer is not me.  Not worth the hassle of trying to resurrect yeast that is totally dead, or to have a wild ferment because the yeast was dead and some other random organism gets in there and you don't even know it.  YMMV

Dry yeast, on the other hand..... dried yeasts keep for many years, maybe even decades, in refrigeration.  This is one of the huge reasons I use dried yeast almost exclusively these days.
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