Volume Loss During Primary Fermentation

I was wondering if any of you brewing have experienced this situation. I’ve been brewing with starters for quite a long time, as I tend to brew bigger beers like barleywines and imperial stouts. For the really big beers like the imperial stout I brewed on Friday (OG was 1.115 on that one), I made a starter of about 3 cups DME to 3 cups water and pitched one package of Wyeast 1028 London Ale into the starter wort (and yes, I smacked the package to release the nutrients). That usually results in a starter of about 1.040 or so and seems to really get the yeast going. I pitched the entire starter into the wort (collected just under 5 gallons and this resulted in being just over 5 gallons after the starter addition) and fermentation began in less than three hours in my 6.5 gallon carboy. By 5 hours after I pitched I needed to install a blow-off tube and as a result of the vigorous fermentation, I have lost at least a quart of wort/foam through the blow-off tube. Seems like the beer is settling down now, but do any of you experience this same problem -- that is, losing beer volume through the blow-off tube? One friend suggested that I might be overpitching in these big beers, so I am trying to find a happy medium between quick fermentation and not losing beer volume to the vigorous fermentation. Thanks for any thoughts you have!

There are a few additives that seem to help keep blowoff down. I had been having trouble with certain "top cropping" strains, even with 2-4 gal of headspace in a 15 gal carboy, but "Fermcap" seemed to really help with those problems. I have not noticed any off flavors, etc.

Yep, Fermcap works wonders.

Sounds great! Thanks for the responses. I was having a bit of trouble with foaming while aerating with pure oxygen, so my guess is that this will help with that foaming as well....

That’s normal, its easy to overdo O2. It shouldn’t cause problems with over foaming though.

Over aerating can cause yeast health problems down the road if you harvest yeast. No need to go more than a minute with a stone and pure O2.

Vigorous top-cropping yeasts just need a lot of head space, especially for big beers. If your not going to get a bigger fermentor, fermcap is the only solution other than brewing smaller batches. Unless you are experiencing almost no lag time or pitching on a whole yeast cake, you probably aren’t over-pitching.

Usually the blowoff looks worse than it is.
I typically don’t lose a lot of volume.

Out of curiosity, why add the whole starter? I always decant to reduce dilution. Plus, starters can produce a more estery product, in my experience, as I tend to ferment starters warmer than primaries to aid with growth. That coupled with increased oxygen due to use of a stirplate lead me to decant...

I always decant my starters due to using a stir plate. That starter wort is oxidized and nasty.

What did you mean when you say you decant your starter? I’ve not heard of this.

Originally posted by BenH
What did you mean when you say you decant your starter? I’ve not heard of this.

Cold crash, let the yeast settle out, pour off 90% or more of the liquid, resuspend the yeast, and pitch that resuspension.