My yeast starter went crazy

I put up starter last night at around 9pm in a 2L Ehrlenmeyer flask, put it on the stir plate and turned it on and left it. At 6am I come downstairs to check on it and it is overflowing, bubbling like crazy. I turned it off to clean up the mess, and it is now off and settling.

At this point I'm thinking I'll have my brew ready by later today, so maybe just turn it back on and let it overflow into something that will contain it. I planned on pitching the entire flask into my brew so no need to let it settle out.

Any opinions?

zacster said:

Any opinions?

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Yeah, a 5 litre flask is better, as you have seen.

I turned it back on and it exploded. At least I had it contained. I've put a sanitized aluminum foil cap on it and I'm letting it sit.

zacster said:

I turned it back on and it exploded. At least I had it contained. I've put a sanitized aluminum foil cap on it and I'm letting it sit.

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Of course it exploded, the beer was full of CO2 and you disturbed it, much like shaking a bottle of soda. Stir it a little and let the CO2 out, let the bubbles subside, then stir it a little again. Repeat until you can let it stir constantly. You need to get the CO2 out of the beer so the yeast can multiply.

Something similar happened to me recently. My stir plate threw the stir bar to the side overnight and when I found and corrected it in the morning, the sudden stirring caused an eruption of foam from the flask. I calmed it down with a couple drops of Fermcap.

I turned it back on, let the gas out, and now it is OK. I lost about 10% of the liquid, so now there is also a little headspace. I'm sure it'll be fine.

I have a gallon jug that I do my starters in. When I have to make huge starters where there is possibility of overflow I use fermcap. It keeps the krausen way down and eliminates overflow.

I switched to a 5l flask. I was sick of overflows and losing a lot of healthy yeast.

Fermcap-S will prevent any problems with starter overflow.

Fermcap-S definitely works as do the larger flasks, but all-in-all, I found starter solutions to be a PITA that I just don't want to work with. I've shifted to dry yeast whenever possible. Quality is up in recent years, price is right, and no starter solution required.

Another long brew day under my belt. The starter went into the wort about two hours ago. I already see some activity.