Minor starter issue.

[Ike]

SO... I made my first-ever starter with a vial of WLP002 and split the result, using half in a 5gal batch of brown ale and saving the other half in two Ball jars in my fridge.

Issue: I've noticed that I apparently harvested the starter before fermentation was complete. Now, even though refrigerated, there is a small amount of fermentation going on, enough to make it hard to "pop-pop" the lid on the jars each day or so. A slight turn of the ring, a very quiet hiss, and we're good again.

The main reason I want to take the best care of this yeast that I can: I hope to continue harvesting starters from this batch, so I don't want it to get infected and want to keep it very healthy. Options I'm considering:

1.) Unify the two jars into one, then leave in the fridge as-is with the ring on the jar JUST loose enough to allow the continuing fermentation gasses to escape;

or

2.) Pull the jars out, drop them in a larger jar, let the fermentation finish up, THEN drop it back in the fridge.

SO, which is the way to go? My greatest concern is the first option's greater chance for infection due to the loose top vs. the second option's greater chance for stressed yeast due to the start-stop-start-stop of bouncing it in and out of the fridge.

Thanks for weighing in!

 

[TheMadKing]

That's pretty normal in my experience. I wouldn't do anything, it sounds like you've got it under control!

Side note: when making a starter you never want fermentation to finish. The goal of a starter is for yeast to make babies, not alcohol so you want to put them in the fridge after 24-48 hours of growth so that the population is at its peak and you have minimal die off from alcohol and age.

It's totally normal for some yeast to still be active, even if they are extremely sluggish. I usually just off-gas mine by loosening the lid until it hisses a couple times during the first week they are in the fridge and then leave them be until I use them. Keeping jar transfers to a minimum is also better because it reduces the chances of infection.

Hope that helps!

 

[wardens355]

I generally just keep the starter on for 48 hours, as long as it shows signs of activity within 12 hours, and then pour in sanitized mason jars and store in the fridge. Some will build a small amount of pressure, but I don't ever open them once I put them in the fridge. Haven't had a cracked mason jar yet (knock on wood).

Side note: when making a starter you never want fermentation to finish. The goal of a starter is for yeast to make babies, not alcohol so you want to put them in the fridge after 24-48 hours of growth so that the population is at its peak and you have minimal die off from alcohol and age.

Do you take the gravity of your starter wort to confirm that you actually harvested before significant alcohol production? I always assume that all my starters are around 2-4% alcohol but have never bothered decanting and adding sterilized water for storage. I'm curious if it is really possible to grow the starter without significant alcohol production. If the starter is being used within a week I don't think the alcohol level is really that big of a deal, but I would be interested in seeing the effect of alcohol on yeast viability over time with refrigeration (Woodland Brewing ABV Effects on Yeast, shows effect at room temp, but not fridge). Some cultures sit in my fridge for 4-6 months and I still grow them up fine based on calculations for yeast pack viability.

 

[ricshayne]

i just leave the lids on very loosely for the first couple of days so the yeast can off gas and push out any oxygen. the co2 pushing out will prevent any bad from getting in.

 

[TheMadKing]

Do you take the gravity of your starter wort to confirm that you actually harvested before significant alcohol production? I always assume that all my starters are around 2-4% alcohol but have never bothered decanting and adding sterilized water for storage. I'm curious if it is really possible to grow the starter without significant alcohol production. If the starter is being used within a week I don't think the alcohol level is really that big of a deal, but I would be interested in seeing the effect of alcohol on yeast viability over time with refrigeration (Woodland Brewing ABV Effects on Yeast, shows effect at room temp, but not fridge). Some cultures sit in my fridge for 4-6 months and I still grow them up fine based on calculations for yeast pack viability.

Good question, no I haven't ever measured mine actually! I'll try that with the next one and get back to you, now I'm curious!

Some alcohol will be produced, but my goal is to keep it to a minimum just to be on the safe side.