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Reviving Year Old Yeast

Posted: Tue Mar 28, 2023 9:15 am
by Jimmy Orkin
I am planning to brew a Pilsner. I had a package of Omega German Lager I that was packaged a year ago. I am going to brew 10 gallons so I need a lot of yeast.

I am doing a 3 step starter: 0.5 liter, 2 liter and 4 liter starters.

I am in the first step now. It has taken 26 hours to see signs of fermentation. I was getting worried during the first 24 hours by not seeing fermentation activity. I had a yeast pitch a couple of years ago that was inside of 6 months of packaging do the same thing.

I assume that there are so few live cells that it just takes 36 hours to make enough new yeast cells to get to the fermentation stage. So I wonder how many cells were really alive after a year.

Here is a picture of the 0.5 liter starter on my stir plate. The reason for the cards on the sides of the flask is the magnets are so strong, the friction will not let the stir bar move if that 1 liter flask sits directly on the cigar box.
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IMG_701702157.JPG (46.08 KiB) Viewed 600 times

Re: Reviving Year Old Yeast

Posted: Tue Mar 28, 2023 12:00 pm
by James Smith
I do it all the time. Unless it is black, I consider some portion of it still viable. Just factor in grow up time. Have had some that take a couple days, but have never not had activity eventually. Then it's just a matter of growing it up. Do you have any estimate of your starting cell count? I have everything to do a yeast count if needed.

Re: Reviving Year Old Yeast

Posted: Tue Mar 28, 2023 7:51 pm
by Jimmy Orkin
I thought about getting Dean to do a cell count. Good to know Smitty, that you can do counts.

The yeast was dark until this afternoon. Now it looks like what I normally see. That cream colored yeast look. The half liter is going into the fridge tonight. I'll start the second step on Thursday.

Re: Reviving Year Old Yeast

Posted: Thu Mar 30, 2023 10:07 am
by Terry Olinger
I did a starter last year on a pack that was 9 months past manufacture date. The first 24 hours saw 0 activity, then went about normal.

Re: Reviving Year Old Yeast

Posted: Thu Mar 30, 2023 10:20 am
by Jimmy Orkin
Terry Olinger wrote: Thu Mar 30, 2023 10:07 am I did a starter last year on a pack that was 9 months past manufacture date. The first 24 hours saw 0 activity, then went about normal.
That is exactly what I saw.