The Great Barrel Top Up Thread

[Bainbridge]

So I haven't found a whole lot of discussion of this on Probrewer and the BA has yet to release a "Wood" book (though they should!). There's a lot of writing pertaining to wine and spirits, but we all know beer is a different beast. So let's talk ullage!

What is your policy on topping up barrels?

I'll start.
For short duration stuff, like fresh whisky barrels with two to six weeks contact time, I don't bother. Just bung it up.
For longer stuff and sours, I've been topping up every month or two. If it's based on, or near to, a year-round beer I'll top with that, but if it's a one-off I save some in kegs for top up later on. Typically I open, purge the headspace with co2, then top up, co2 blast again, and bung it.

I can see the argument made that every time you open the barrel there's another chance for infection, oxidation etc, and disturbing the pellicle on sours, but at the same time too much 02 in the head space will encourage acetobacters.

[Inthelab]

I think you're hitting the nail on the head. Top it up.

[AnthonyB]

For non-sour beers, I think your technique and concerns sound reasonable.

For many sour beers, the yeast/bacteria will throw up a pellicle and that will protect against excessive oxidation. By introducing more beer in there, you're taking the chance of disturbing or breaking up the pellicle which will definitely introduce more oxidation.

[SouthHouseBrew]

Pellicle Protection?

For non-sour beers, I think your technique and concerns sound reasonable.

For many sour beers, the yeast/bacteria will throw up a pellicle and that will protect against excessive oxidation. By introducing more beer in there, you're taking the chance of disturbing or breaking up the pellicle which will definitely introduce more oxidation.

A pellicle might slow the movement of O2 from the headspace into the beer, but I don't buy it.

If there is an interface between air (High O2 concentration) and beer (low O2 concentration), oxygen from the air WILL eventually make its way into the liquid - equilibrium will not be denied.

The best way to keep oxygen out is to minimize air/liquid contact (top up) and oxygen content of that air (purge headspace with CO2).

P.S. Sounds like that book 'wood' be a fantastic addition to the BA library...

Ok. I'll stop now.

[Inthelab]

A pellicle might slow the movement of O2 from the headspace into the beer, but I don't buy it.

I would love to see some good scientific research in the whole "Don't disturb the pellicle" mentality since it seems so dogma driven.

[Bainbridge]

Exactly. And since there isn't a lot of actual public research going on, though I'm sure breweries that do lots of barrel beers have conducted their own in-house experiments, I created this thread to help gather anecdotal evidence from The Great ProBrewer Hive Mind.

Judge: Mr. Hutz we've been in here for four hours. Do you have any evidence at all?
Lionel Hutz: Well, Your Honor. We've plenty of hearsay and conjecture. Those are kinds of evidence...

Started a four wine barrel sour project about two months ago. Base beer is dark, 7ish percent, fermented with US05 then into the barrels. One barrel got a pitch straight away of bugs from another sour barrel project (several brett strains, lacto, pedio, delicious dregs from commercial bottles, etc., but saved in a growler in the cold room for about three years. My old homebrew club had brewed the sour for the 2009 NHC in Seattle!) The second got a pitch right away of bugs from the second use of the barrel from that first project, which was good but had picked up a little aceto along the way. The other two got nothing while I grew up some Brett Brux and Brux var. Trois. Pitched brett slurry into all four barrels this Saturday, about two months after the beer went in. In the two barrels that had nothing pitched, there were a few floaty yeast, and possibly mold, colonies on top. In the barrel with the pitch from the second use from the other barrel, there was the beginnings of a pellicle forming. Little colonies with strands starting to connect them. In the first barrel, with the 3 year old first use pitch, there was a solid, if thin, pellicle across the entire top! Disturbed as little as possible, then hit the top with co2 and bunged them back up. Added about a liter of brett slurry to each barrel, but otherwise did not top them up. (I'm out of the base beer, but we've got a Baltic Porter in the pipe that should top it up nicely in a couple weeks.)