Kriek Headspace Anxiety, Illustrated

TristanLowery · 02-07-2012, 12:32 AM

Last January I brewed a Flanders sour brown with the intent to use it as a base for a Kriek, as Liefmans does. It's been on the Wyeast Lambic Blend and Calvados-soaked oak cubes for a year now. Everything's been going swimmingly - no complaints thus far. But about a month ago I racked it (three gallons - I brew smaller batches) onto six pounds of local sour cherries I froze last summer in cryovac bags. In order to allow for the displacement produced by all that fruit, and also to keep my mind at ease after reading about fruit-clogged carboy explosions, I've got it all in a 5-gallon Better Bottle now, which leaves more headspace than might be ideal.

It's only been like this for a month now. I'd like to keep this on the cherries for at least six months, but I wonder if I should worry about oxidation or acetic acid production with this much headspace. I could rack it back into a 3-gallon carboy prematurely if need be, but I'd prefer to keep it on the fruit if it doesn't seem like a concern. Has anyone else had experience with long-term aging of sour fruit beers with such generous headspace? This beer is tasting great after a year and I brewed a second batch last month to blend in another year. I have a lot invested in this and don't have any use for three gallons of cherry sherry vinegar.

Here's what I've got now. I don't have the gear to purge this carboy with CO2. On tghe other hand, I haven't and don't plan on opening this up for any reason. Will CO2 and the Brett pellicle - not to mention the cherryt minefield - be sufficient to keep the oxygen at bay?

TristanLowery · 02-07-2012, 12:34 AM

Oof. First time uploading a photo onto Homebrewtalk and it's too big and sideways. Sorry!

dougdecinces · 02-07-2012, 01:39 AM

Two thoughts:

1) The yeast should have metabolized some of the sugars in the cherries, providing a CO2 "blanket".

2) If you are still concerned, you could always brew a small one gallon batch and pitch it straight into that carboy. If it is going to sit forever and a day, then adding more wort is not that big a deal.

boostsr20 · 02-07-2012, 02:10 AM

Quote:

Originally Posted by dougdecinces

Two thoughts:

1) The yeast should have metabolized some of the sugars in the cherries, providing a CO2 "blanket".

2) If you are still concerned, you could always brew a small one gallon batch and pitch it straight into that carboy. If it is going to sit forever and a day, then adding more wort is not that big a deal.

Agreed.

Homebrewtastic · 02-07-2012, 04:03 PM

If you're set up to keg you could transfer it all into a keg, displace the oxygen with some co2 then remove your out post and replace it with an airlock.

TristanLowery · 02-07-2012, 04:41 PM

Kegging's not an option - I'm still a stubborn bottle-conditioner. Capital idea though, adding more wort to displace the headspace, especially as I've got the day off and just enough of the necessary malts to make a 5-liter top-up batch. I'll do that, since no one has attempted to persuade me that that muh head-space isn't going to be a problem, and anyways, it's more beer in the end, right?

I should be good siphoning the chilled wort straight into the half-empty (or half-full) carboy, correct? Need I bother with aeration or more Saccharomyces? It's been over a year, but there's plenty of microbial life in there: Wyeast's Belgian Ardennes and Lambic blend, dregs of Boon, Orval, Jolly Pumpkin, a homebrewed Berliner with Brett. They shouldn't need any help, I wager.

Thanks for the help, everyone.

dougdecinces · 02-07-2012, 05:05 PM

Just stir it vigorously after it cools to aerate. Then you can siphon it into the carboy.

**stubbornman** · 02-07-2012, 05:29 PM

I don't think I'd aerate it. The aeration phase is for yeast reproduction, which won't really be needed, and you don't want to introduce the O2 into the overall beer at this point.

I'm with you, just chill and add to the fermenter.

Homebrewtastic · 02-07-2012, 05:58 PM

Quote:

Originally Posted by TristanLowery

Kegging's not an option - I'm still a stubborn bottle-conditioner. Capital idea though, adding more wort to displace the headspace, especially as I've got the day off and just enough of the necessary malts to make a 5-liter top-up batch. I'll do that, since no one has attempted to persuade me that that muh head-space isn't going to be a problem, and anyways, it's more beer in the end, right?

I should be good siphoning the chilled wort straight into the half-empty (or half-full) carboy, correct? Need I bother with aeration or more Saccharomyces? It's been over a year, but there's plenty of microbial life in there: Wyeast's Belgian Ardennes and Lambic blend, dregs of Boon, Orval, Jolly Pumpkin, a homebrewed Berliner with Brett. They shouldn't need any help, I wager.

Thanks for the help, everyone.

I would throw in a pack of us05 or notty just to be sure. If its at a year then your critters are probably going to be more active than your yeast and therefor may take some time to build up the desired amount of co2.

Another option (again to make sure you have adequate and vigorous fermentation) is to get your 1 gallon batch fermenting and then dump it in with your big batch.

ReverseApacheMaster · 02-07-2012, 08:49 PM

If there isn't a pellicle after a few weeks that would indicate the layer of CO2 is dense enough that significant amounts of oxygen is not getting to the beer. There's enough sugar in the fruit to have kicked off enough brett fermentation to form a pellicle. It doesn't take much.

If a pellicle rises I would be concerned about headspace and either add more wort or CO2.