Yeast starter size vs. flask size

[Hsocain]

So I finally got a stir plate and erlenmeyer (sp?) flask. So now I don't have to make starters in my growlers. Question, I usually make 2L starters, but I have a 2L flask. Will that hold a 2L starter? Thanks, Steve



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[BrewerBrad82]

It sure will work. A normal 2L flask usually will hold more than 2L, so you will have some head space when you add a full 2L to it. Normally the 2000ml graduation on the flask leaves plenty of space. You will be just fine, especially on a stir plate!

 

[WI_Wino]

You will need to be vigilant if boiling 2L of wort in a 2L flask though. I manually modulate my stove burner to keep from boiling over.

 

[Gduck]

The one thing to be careful of is if you heat it directly in the flask - you'll really have to keep a close eye on boil overs. I generally use a drop or two of formal shortly before it reaches a boil and haven't had an issue. Once it's cooled down and on the stir plate there shouldn't be any problems.

Though recently I purchased a 5l flask when it was on sale so that I had the extra space and the option to do bigger or step up a starter if I really feel the need.

 

[mliptack]

Depending on the yeast and temp of the starter, I find that with a 2L Flask, I am limited to about 1500-1600ml. If I go any higher than that at ~68-70deg F, the krausen will flow out and basically glue my flask to my stir plate. If I need a 2L starter, I will take 2 steps to get there. 1st step with about 800ml-1L of wort. Ferment for 1-2days, chill, decant off the excess. 2nd step ~1200-1400ml added approximately 12-16 hours before I brew (lighter beers I will decant - darker, or stronger beers I will pitch without decanting).

I've been eying up a 5000ml flask...

 

[Hsocain]

Thanks for the responses.


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[WI_Wino]

Here's a pic of my 2L flask with just under 2L of wort. I boiled this last night on my gas stove and pitched a hefeweizen yeast after it cooled. Solid ferment going on now but minimal krausen with the stir plate going.

View attachment 1419895482083.jpg

 

[Natdavis777]

Per a Northern Brewer PDF, they classify a 2L starter as "1300ml water and 1 cup of DME." Even after pitching the liquid yeast packet (125ml), there isnt near 2L of fluid. I attached the file. I usually stick to 1600ml starters and do a two-step for lagers I use brewers friend yeast calculator

View attachment YeastStarter.pdf