Infection showing only after 6 months in bottle?

[Hektor]

hi All,

I am having a strange thing happening to a few batches of beer I brewed. One is from back in August, the other from back in October.

they were three different recipes, came out of fermenter tasting great. Got bottled, tasted great... And I left some of them on the floor in a tiled room that has underfloor heating (which turned on without my knowing) for 6 months and now three of the batches of beer foam enormously when opened and have a strange taste that I can best describe as "carpet / carrot". The beer were fine up until a month ago.

I am wondering if the underfloor heating caused this? Can yeast autolyses do this?

Or could it be infected by something that takes a very long time to grow in the bottle (we are talking up to 6 months here) ?

I am extremely strict in my cleaning an disinfecting, using StarSan, PBW as well as regular odourless dish soap to clean out fermenters etc.

I'm scratching my head because I have never had this before...

Thanks!
H

 

[mashdar]

Is it uniformly all bottles of the batch?

Maybe heat cause increase attenuation, but that wouldn't explain the flavor.

Cooked yeast? Is the floor electric or hydronic?

 

[Hektor]

Yes and no, I only had this with the remaining bottles from different batches that I had sitting on the floor... Different recipes (one a 4.2% light ale, another a 7.5% heavy christmas beer) in different bottles sizes too, some in 75cl some in 50cl, all started foaming at the same time (about a month ago), all were primed correctly and were perfectly fine (no foaming, no off flavour) until about a month ago.

Floor heating is hydro based, under the tile. Temp on floor ranged from 22°C to 26°C (depending on the spot on the floor), measured it last week.

 

[mashdar]

Hmm hydronic probably wouldn't cook it the way electric could. But it almost had to be the floor, if it happened to different batches like it did.

26C? I would expect a floor loop to operate at ~36-40C, although I don't know what the surface temperature woud be. (Close to loop temp when covered by boxes, I think.)

I think you're right that the flavor is lysing yeast, and the carbonation is from higher attenuation from the temperature change.
(edit: I've read 0.001 gravity change gives 0.5 volumes, so it wouldn't take much to get gushers. You could check gravity to compare with your records. I bet it dopped a few points.)

 

[mac_1103]

I don't see how increased temperature will increase attenuation if there are no extra fermentables present. IOW, unless the beer wasn't finished when it was bottled or too much priming sugar was added. Which would eventually give you gushers even without the heat.

 

[RM-MN]

Or could it be infected by something that takes a very long time to grow in the bottle (we are talking up to 6 months here) ?

Wild yeast could do that and they can also eat some of what was not fermentable to the other yeast. If you got only a little of the wild yeast it could take a long time in the bottle to build up its numbers to be able to create enough CO2 to make the beer foam. Look around your neighborhood for possible areas that the wild yeast could have come from. In my case it was apparently a huge pile of corn silage because when the pile went away the problem did too.

 

[Teufelhunde]

You have 6 month old beer???????????

 

[mashdar]

I don't see how increased temperature will increase attenuation if there are no extra fermentables present. IOW, unless the beer wasn't finished when it was bottled or too much priming sugar was added. Which would eventually give you gushers even without the heat.

Within reason, yes, but if you heat beer to 100F/40C, all kinds of metabolic processes become more favorable. It wouldn't take much, particularly in the bigger beer.

That it happened to all bottles in multiple batches with similar timing does not sound like small scale contamination to me. (Although the heat could drive that, too...)

 

[mac_1103]

if you heat beer to 100F/40C, all kinds of metabolic processes become more favorable

OP says he measured the temperature on the floor and it was 22-26C, not 40.

 

[mashdar]

OP says he measured the temperature on the floor and it was 22-26C, not 40.

OP measured what must have been uncovered surface temperature. Radiant floors would not be designed at 26C water temperature, and surface temperature will approach loop temperature if covered with cardboard boxes. (I asked about electric because those can get very hot when covered.)

The long delay followed by sudden, complete multi-batch issue is not hallmark infection. You'd either expect rapid effects from major infection, or sporatic gushers (and bombs?) from minor innoculation.

The floor is a stretch, but is the only option presented so far that fits.

 

[mac_1103]

Well I do agree that the floor is a stretch. And I think you are significantly overestimating the R-value of a cardboard box.

 

[lumpher]

I've had that happen. Back when I bottled, I had a Porter that was 8 months old stored in a closet. 1 day I was driving somewhere, and my wife called me and told me she heard 2 shotgun blasts from our home office. When I got home, I cleaned up the glass, including some stuck in the back of her chair about 3" from where the back of her head was at the time (computer desk)... then I scrubbed down the ceiling, chilled those bottles and drank what I could, threw away all my bottling stuff, and started kegging.