Yeast starter has sat for over a month - still good?

Yeast & Fermentation
1

Hi. I had plans to make a saison using WLP590 yeast well over a month ago. I made the starter (in a flask on a stir plate with an airlock bubbler) on a Thursday with plans to brew that Saturday, but we unfortunately had a tragedy in the family on Friday, so obviously, the brewing didn’t happen. The yeast starter has been in the flask with the airlock in the refrigerator ever since that weekend. I saw another somewhat similar post, and a response was to make another starter batch. I just wanted to clarify if I would be able to make a starter batch out of my existing yeast in the refrigerator, or if I need to get new yeast. Thanks.

Frank

2

To be on the safe side I’d just get fresh yeast and make a new starter.

3

I’m in the “step up your starter” camp. In my mind, by doing your previous starter, you made fresh yeast. If you got a smack pack that was one month old, you’d probably be pretty pleased with the freshness.

1 Like
4

You have yeast that is only one month old. It has lost some viability. You may need to use this yeast in fresh starter wort if the amount of yeast propagated was the minimum for your brew. Put your numbers in this pitch rate/starter calculator for an estimate of viable yeast cells on hand.

Remove the airlock and cover your flask with sanitized aluminum foil. The foil cover will allow CO2 to escape and air to enter to provide oxygen for the growth of new cells.

5

Definitely use it and step it up. Absolutely no reason to waste it. The “fresh” yeast you buy from the store may be a month old.

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6

Don’t throw that away!!! Add more wort and then brew!

7

And there you have it, the wisdom of the the readers whom have done many brews, and I would say to make a weak wort and add to yer decanted yeast and spin it again. Sneezles61

8

Good evening gents. I believe the starter I created would have been more than sufficient for the gravity of beer I’m planning to brew (I ran the numbers beforehand). Given the general advice here, I’ll make another starter batch, though, decant the flask, and pitch into the starter and let it spin a day or two. Thank you all for your advice. Much appreciated.

Frank

1 Like
9

It very well may have been big enough when you finished it the first time. However you lose viability as it sits. That’s why flars suggested you run it through the calculator to see how many cells you may have lost and determine if you need to step it up again.