Beer Forum

Hi all,

I usually keg, but I'm trying to figure out a process for bottle conditioning. I ferment in a cool environment using a fermwrap and a temperature controller, so I can keep fermentation within a degree. I just bottled a Robust Porter and since I can't control the temperature of all those bottles evenly with the fermwrap, I just stuck the boxes of bottles in a closet to carbonate. Occasionally looking at a thermometer in there, I've seen a temperature fluctuation between 62 and 66 degrees F. I guess I'm wondering if I can expect any problems from these temperature fluctuations. It seems to fluctuate slowly, but it seems like a big swing nonetheless.

Pertinent info: Robust porter based on recipe in BCS. Used Wyeast 1056 from a starter, fermented at 67 deg F for 6 days, ramped up over 4 days to 70 deg for Diacetyl rest, hung out there for 4 days then bottled. OG 1.072 ( high, I know ) finished at 1.017, abv about 7.5%.

Thanks for any thoughts on it.

Toast

I wouldn't worry about it. By the time you're in the bottle, 4 degrees isn't really anything. You may want to get them a little warmer though. They'll carb up at those temps, but it'll take a bit longer.

Yup... yep.

Thanks, craning does seem to be a little slow. I'm looking at getting the temp controlled on these bottles. What do you think of setting the fermwrap flat in a box, sitting the bottles on top of it, then rubber banding the four center bottles around a ranco temperature probe? Seems to my Red ale addled - 1am mind that the heating might be even enough if I set the controller to like 68 deg F. I shouldn't over heat, right? Anyone do this ever?

Thanks all!
Toast

Personally I think you're over thinking it. Find closet. Insert beer. Wait 2 weeks. Retrieve beer. Done.

Closet at 68? Great. Closet at 72? Great. Closet at 88? Great. Closet swings from 68 to 88 daily? Totally fine. You're just getting the yeast to eat a little sugar to make some carbonation, not fermenting. Don't worry about it.

Once you're in the bottle and they're carbonated, I think you only need to worry about those huge temperature swings like from the hot beer truck to a cooler, to the hot trunk of your car, to the beer fridge.

I just naturally carbonate a dark mild in a keg in the spare bathroom. Temperature swings from 65-75 throughout the day and it came out great.

Ozwald wrote:Personally I think you're over thinking it. Find closet. Insert beer. Wait 2 weeks. Retrieve beer. Done.

Yup, yep, yup, yup, yep.

Temp swings of 3+ degrees are so often thought of as 'bad' round these parts from all the talk of temp control over the years without being specific about when it's important & the impact it'll have at the various stages of fermentation.

The most critical time for temp stability is the period from when you pitch until you have an active fermentation. During this time they're busy uptaking nutrients & producing more cells. If the temp goes up a few degrees, they have no way of knowing if that temperature trend is going to continue, so the response is to adapt which is going to create a lot of off-flavors, mutations & generally unhealthy cells (for our purposes). The next most critical time is the period from the beginning of active fermentation until it begins to slow - about 2 or 3 days. They're no longer reproducing (in a way that we really care about), but they'll still respond unfavorably to temp swings & produce off-flavors. As fermentation is winding down, the temp swings won't affect them as much while they work into a dormant phase. There won't be as many cells still working, the ones that are still working aren't very active & are going to be much slower to respond to their environment. It still can potentially pose an issue, but not even close to the effect that temp swings have on the larger, more active population in the previous life cycle. A swing of 6 degrees at this point is likely to have less of an effect at this point than a 3 degree swing would a few days earlier. After they've flocculated & fallen out of solution, there's next to no activity at all, so their response is going to be in a similar state.

Just like stated before regarding a hot car, it really takes some abuse at this point to get a response at all, such as the hot environment, 20+ degree swings & being disturbed by either the vibration of the vehicle or general handling. Even the tiny bit of priming sugar isn't enough to rouse them into another sensitive cycle. It's more like giving Spider a cookie after a Paxton dinner. He'll loosen his belt (which won't make much sense since he's not wearing pants), take a look at the cookie & get around to it when he feels like it. Other than the Kenny G record playing in the background, his environment won't be effecting him like when he's active & hungry. Instead he'll just be a lazy fat load sitting on the couch waiting for Pax's prime rib to digest not giving two shits what the thermostat is set to.