Is it safe to bottle?

[lightmedium]

Hello HomeBrewTalk! I'm new to home brew, getting ready to taste my first batch, bottle my second batch, transfer my third batch, and brew my fourth batch today. Big day!! I'm worried about the bottling though. The beer is a kolsch, the yeast is WLP029. It spent a week in the primary at 62 degrees and two weeks in the secondary. Of those two weeks in the secondary, the first 4-5 days were at about 60 degrees, and the remainder at about 50 degrees (on my garage floor). I moved it in last night so it could settle before moving to the bottling bucket and, to my surprise, there are clusters of CO2 bubbles covering about 60% of the surface, and the airlock is bubbling about 1 bubble every 40 seconds or so. I thought it might just be expansion as it warms back up again, but the bubbles on the surface suggest fermentation. I'm wondering if I cooled it down too soon, but from what I understand, Kolsch is usually done fermenting in 4-5 days. I let it go a week, and then another 4-5 days at fermentation temp. Should I be concerned? Should I avoid bottling for a couple days? Whattayall think?

-Mike

 

[aiptasia]

I don't think it's going to hurt to let it sit for a few more days. It does sound like there's some residual fermentation going on. I'm betting the yeasts slowed down with the cool temperature drop prior to complete fermentation being done.

The only way to really tell if the fermentation is done is to use a hydrometer or using a light refractometer. Once the readings are the same for 2-3 days, it's usually a sign the primary fermentation is complete.

To avoid a bottle bomb situation, let it sit and keep an eye on it.

 

[eastoak]

a refractometer is not the best thing to use to check final gravity. take a hydrometer reading 3 days in a row and if it's the same reading your beer is done fermenting. you could let it sit another week or more or just go ahead and bottle, depends on who you ask but it does not matter much.

 

[kh54s10]

a refractometer is not the best thing to use to check final gravity. take a hydrometer reading 3 days in a row and if it's the same reading your beer is done fermenting. you could let it sit another week or more or just go ahead and bottle, depends on who you ask but it does not matter much.

A refractometer is fine for checking that fermentation has finished. Several identical reading and it is done. Alcohol skews the numbers seen so it is not so good for getting a final gravity reading. There are calculators online to compensate for the alcohol. How accurate they are is debatable.
The Hydrometer is best to get an accurate number for final gravity because the presence of alcohol does not skew the numbers.

The bubbles could just be co2 coming out of solution because of the temperature change.

 

[ghpeel]

When beer in the carboy or secondary warms up, the C02 in suspension bubbles out. It does not necessarily mean that fermentation has begun again. Give it another day or two at a stable temp indoors to double-check, but you are probably safe bottling if you have too right now.

 

[lightmedium]

Thank you everyone! I think a few days of watching the gravity is a small price to pay for avoiding bottle bombs. I'm 99% certain that it's done. Unfortunately, I slacked on the hydrometer readings in the beginning. I assumed that, since airlock activity had stopped and the beer was in the primary 3x what it "should have taken" for fermentation to finish, that I was safe to start the chill. Now I can really only guess. This is probably just CO2 coming out of suspension, as kh54s10 and ghpeel pointed out, but this is my precious second batch... so I'll be safe and wait. I'd RAHAHB, but I don't have any done yet!! Thanks again everyone!

 

[Calder]

I just checked White-Labs site and it says "Does not ferment well less than 62°F, unless during active fermentation." Due to your low temperatures, the yeast may have gone to sleep and not finished off the beer.

You need to bring the fermenters inside, let the beer warm up to room temperature and leave it for a few days to see if fermentation starts up again.

Also, take an hydrometer reading to see if you are around the expected FG. If you want to know what your OG should have been, post your recipe and someone will work it out for you; if it was extract, it is pretty easy to do.

 

[lightmedium]

Thanks, Calder! It's still bubbling today, so I'm leaning toward the likelihood that I cooled it off too soon, like you say. I'm going to continue checking the gravity and bottle once it stops dropping.