What's considered a "large" starter?

[ccfoo242]

Is 2.5L considered a large starter? I ask because most instructions suggest larger starters should be cooled and the wort decanted before pitching. But I have seen anyone mention what the cutoff is before a starter is considered large.

Also, is 2.5-3L too large for a single starter or does it need to be stepped up?

[brewinhard]

It really depends on the size of the batch you are doing and the original gravity of the beer you are attempting to ferment. The age of the yeast vial/package also can influence the size of a starter. Your best bet is to check out Mr. Malty's pitching rate calculator to determine these factors and help you create a proper pitch rate for your beer.

2.5-3 Liters of starter is not necessarily too large for a single package of yeast. It really depends on the size of container you plan on using for your starter. I would say that anything above 1.25-1.5 L should be properly cold crashed for 24-48 hrs and then carefully decanted before pitching so as to avoid any off-flavors from the pre-fermented starter wort and warmer than average propagation fermentation.

[ccfoo242]

Thanks for the info. It's a 5 gallon batch (Rogue I2PA all grain clone sold by morebeer). I guessed on an OG of 1.080 for Mr Malty's site and get around 2.6 liters of starter using 1 yeast pack. I have a 1 gallon container I can use for starters.

[Tygo]

I've seen a rule of thumb mentioned before that if the starter volume is less than 10% of your batch volume than you can pitch without decanting.

But take that for what it's worth. Personally I like to pitch as little of the starter wort as possible into the batch so I almost always chill and decant no matter what the size.

[spiderwrangler]

The idea there is that the starter wort is not the wort you are trying to make the beer out of so you'd be diluting it if you add a big vol of starter.

The other thing is if your starter was continually oxygenated (stirplate, etc), the spent starter will have an oxidized character that you want to decant off before pitching. For decanted starters, you want to let it go to completion then crash as opposed to pitching at high krausen.

[ccfoo242]

I assume I need to warm it back up to pitching temp after that?

[spiderwrangler]

I decant at the beginning of brew day and let the flask sit out while I brew, then swirl it and pitch it when everything's chilled.

[ccfoo242]

Great, thanks for the info!