Viscous film in a used whiskey barrel

[BigPerm]

I've been brewing for about 13 years, but the last year or so of playing with sour beers has definitely been the most fun!

I have a used 5-gallon whiskey barrel that was previously used to house two clean beers, which turned out great. I racked the last one (an imperial rye smoked porter) out of in March. I didn't have anything coming up for it, so I rinsed it several times with boiling water to get out the flavor and trub, and finished with 3 gallons of boiling water. It sat like this until today, with the intention of the next beer being used to sour the barrel.

I brewed an Oud Bruin with L. brevis which has largely finished the initial fermentation, and planned to transfer that to the barrel for a short period before transferring in my sour stout. When I drained the barrel today, a viscous white film came out and I got more out with 2-3 rinses. The film is white-offwhite with some yellowish spots, maybe 1/8" thick with some structure to it, slimy but not excessively so. I initially suspected acetobacter (due to the headspace), but the film had no aroma, and the water drained from the barrel did not taste of acetic acid at all (yeah, of course I tasted it.) The barrel smells sweet and clean, with slight residual whiskey and oak. To be safe, its getting 2-3 boiling water rinses. The wood cellulose would have been the only real food for anything to grow on (not that that isn't enough).

My question is really whether anyone has seen this and what they did about it. Anybody have any idea what this is? I'm a little nervous to put good beer in there (but not so much so that I'm not going to do it). I'm just trying to decide if I want to brew a simple wort and see what happens to it.

Any thoughts are appreciated. Thanks!

 

[smokinghole]

My initial thought is that you have bacterial cellulose there. However I did find a waxy film come out of my barrel when I rinsed it with hot too. So there's a chance your barrel had internal waxing to keep it from leaking (I think it's common on smaller barrels) and the wax combined with other stuff to make a weird slimy film. I'd toss a sour in there and just get along with your life. If it doesn't smell bad and or taste bad I'd just rinse it again and maybe give it a good soak with soda ash very mildly caustic if you want to go a step further and then a rinse with citric acid.

 

[milldoggy]

Did you just store it with water? You should store it with a combo of citric acid and metasuflite. That will inhibit any growth. Not sure what you have, just commenting that storing only with water is not recommended.

 

[milldoggy]

This is a great article
http://morewinemaking.com/articles/Oak_barrel_care_guide

 

[flars]

Looks just like the film that appears in my water tray when using an aquarium heater to keep a fermentor warm.
I am guessing what I have is bacterial growth. Next time I will use the anti-bacteria tablets that are used in aquariums. Tetracycline I think. I doubt if this method could be used in a wooden barrel, might be harmful to yeast.
If this was my barrel I would use a blow torch to scorch and sanitize with the dry heat.

 

[roink]

I am guessing what I have is bacterial growth. Next time I will use the anti-bacteria tablets that are used in aquariums.

Just a little bit of bleach would propably
be a much cheaper solution.

 

[BigPerm]

My initial thought is that you have bacterial cellulose there. However I did find a waxy film come out of my barrel when I rinsed it with hot too. So there's a chance your barrel had internal waxing to keep it from leaking (I think it's common on smaller barrels) and the wax combined with other stuff to make a weird slimy film. I'd toss a sour in there and just get along with your life. If it doesn't smell bad and or taste bad I'd just rinse it again and maybe give it a good soak with soda ash very mildly caustic if you want to go a step further and then a rinse with citric acid.

That's an interesting thought. I rinsed with hot water quickly but never let it soak for an extended period before this wash. I guess that could possibly explain it. I'm rinsing with boiling water until I get nothing else out, then soaking and rolling with it. Think that's enough? I'm not overly worried, because it really only smells of slightly sweet wood...

I have a sour stout that derived from a partigyle on a RIS. If it ends up horribly, I'm really only out a yeast pack and some dregs from some damn good beers (oh yeah, and a barrel...)

Did you just store it with water? You should store it with a combo of citric acid and metasuflite. That will inhibit any growth. Not sure what you have, just commenting that storing only with water is not recommended.

I didn't do this, largely because I wasn't sure when I was going to fill it next and i didn't want to leach out all the remaining oak/bourbon flavor. As it turns out, that wasn't the smartest move, but hindsight is 20/20....