Overflowing Starter

I made 1800 ml of wort at 1.040 in my 2 liter flask, pitched a vial of WLP001 and placed it on my stir plate. It was covered loosely with sanitized aluminum foil. After about 24 hours I came home to find that it was foaming over and making a mess. I make starters all the time and have never had this happen. Is this going to be a problem, and how should I avoid this in the future? I am thinking I may need a larger flask for starters of this size.

Two things:
- don't make a first step starter greater than about 1.25L in a 2L flask without fermcap. I often go to 1.8L on second step starters in a 2L flask with 4 drops fermcap. It still foams though, so it requires monitoring but is doable.
- your yeast kicks ass. Salvage what is left and make a new starter if you can.

It's happened to me with WY3068 - that thing was a monster! And yes, a larger flask will help with the mess in the future.

Fermcap, wax paper over stir plate

Thanks for the info, I'll have to get some fermcap. I usually make 1200ml starters, I made this one larger because I wanted to harvest some of the yeast before I pitched.

I make 1.5L starters and use a sanitized foam stopper.

If you don't use fermcap, just be mindful of the yeast being used and give it enough room to work. I made the mistake of making a 2.5L starter of 3787 in a 3L flask on a stir plate. NEVER DO THAT!

LOL pep talking them to not blow off DOES NOT WORK EITHER

Once was enough for me. Now I only fill my starter vessel about half way.

So I'm confused. I have not had any appreciable foam on a starter because, I assume, the stirring action keeps the bubbles knocked down. But I only have made a 1 liter starter so far; does this effect change as the flask gets more full?

Steve

yso191 said:

So I'm confused. I have not had any appreciable foam on a starter because, I assume, the stirring action keeps the bubbles knocked down. But I only have made a 1 liter starter so far; does this effect change as the flask gets more full?

Steve

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It really depends on the yeast and yes, as you get closer up the neck of the flask the risk becomes greater.

+1 on the fermcap. I do 2L starters in a 2L flask. One drop of fermcap and no foam at all. It also lets me boil in the flask without boil over.

yso191 said:

So I'm confused. I have not had any appreciable foam on a starter because, I assume, the stirring action keeps the bubbles knocked down. But I only have made a 1 liter starter so far; does this effect change as the flask gets more full?

Steve

Click to expand...

Take that 1L and step it up again, and you'll see what we mean.