[mdbrew]

I made an Oktoberfest last month and the recipe called for Wyeast 2112 | California Lager.  Based on some feedback I received on another post, I decided to do a semi-lagering phase and chilled it down to 40°F.  Before dropping the temperature, I checked the S.G. a few days in a row and it was holding steady at 1.016, which was a little above the estimated F.G. of 1.013.  No big deal I figured.  So, I've had it in my freezer for two weeks and decided that I would bottle it today.  I was brewing another beer this morning so I took the carboy out of the freezer to let the Oktoberfest warm up a little before bottling.  As it warmed, I noticed signs of fermentation - a lot of bubbles on top of the beer (that weren't there when I took it out) and the air lock was bubbling every five seconds or so.  I took another reading at the S.G. was at 1.013. Should I let the beer ferment at 65°F for a few more days and check the S.G. again?  I'm afraid if I try to bottle it now, I might get too much carbonation in the bottles.  This is my first attempt at a lager so I've never experienced this situation before.  Thanks!

[Jeff M]

Bubbles dont necessarily mean fermentation. As i understand it as CO2 warms up it expands, so all you could be seeing is the remains of fermentation co2 coming out of suspension in the beer.

2cents

[erockrph]

Going by airlock activity is far from reliable as far as tracking fermentation progress goes. As mentioned before, the solubility of CO2 in beer decreases as the temperature rises. When the beer warms up you will have CO2 leaving solution for a while. As long as the gravity reading stays the same, it's done. Monitoring gravity is really the only accurate way to track fermentation progress.

[Slowbrew]

If you didn't warm up your previous samples you are also seeing how temp affects the density of liquid.  Colder liquid is more dense so the gravity will read a bit higher.

Paul

[majorvices]

What the others have said. Most likely it is finished. Bubbling airlocks are a poor way to determine fermentation, as all it means is co2 is coming out of so,union, which can happen weeks after fermentation has finished and especially as the beer warms up.

[mdbrew]

Thanks everyone - I hadn't even thought about the trapped C02 and it makes perfect sense. Just so I don't end up with over-carbonated beer, what's the normal bottling procedure for lagers?  Do you normally let it warm up before adding the priming sugar and bottling it?  I put it back in my freezer with my most recent batch and I have it set to around 65°F at the moment.  I really haven't been able to find anything about the differences (if any) between bottling ales and lagers.  Maybe I'm just not using the correct search parameters.

Also, I do realize that S.G. is the best way to determine if fermentation has finished or not.  As I mentioned, I had gotten the same reading 3 days in a row, so I had it in my mind that it was done.  I think the bubbles and air lock activity just threw me off.  Thanks again!

[erockrph]

When I bottle my lagers I prime and bottle them as I would with an ale. Then I let them carbonate fully at room temp (about 3-4 weeks). After that I cold condition (aka, lager) them in the bottles. Just make sure you use the highest temp the beer reached when you use a priming sugar calculator. In other words, if you brought it up to 60 or 65F to finish up, use that temp in your calculator and not your lower main fermentation temperature.

[mdbrew]

When I bottle my lagers I prime and bottle them as I would with an ale. Then I let them carbonate fully at room temp (about 3-4 weeks). After that I cold condition (aka, lager) them in the bottles. Just make sure you use the highest temp the beer reached when you use a priming sugar calculator. In other words, if you brought it up to 60 or 65F to finish up, use that temp in your calculator and not your lower main fermentation temperature.

Thanks for the advice.  I have it sitting at 65°F at the moment, so I'll take that into consideration.