temperature changes in fermentaion.

Ok so I live in philadelphia and im keeping my fermenting beer in the basement. I noticed its been a week and a half and there is still a little fermentaion going in my fermenter. The airlock still has a little bit of bubbles. I'm just curious if the temperature drops during a really good ferment can that kinda slowfermentaion down a lot?

I only ask this because in philadelphia around this time of year the temperature fluctuates alot.

You really need to check the specific gravity to know if fermentation is done. Beer can "off-gas" CO2 for some time after fermentation is complete, particularly in a temperature shift from cold to warm. Colder beer holds more CO2 in solution. When it warms up, CO2 comes out of solution. This could be the bubbling on your airlock.

But to answer your question, yes, colder fermentation temps can slow down fermentation, so it could be that too. Check the SG to find out.

I'll check it again when I get home... when i looked at the beer on tuesday there were still some bubbles on top of the beer and the sg levels where in the beer level on my sg reader.

You should also consider better temperature control. Yeast don't like a temperature roller coaster.

Eric

What is your present gravity compared to you OG and compared to your target final gravity?

Your basement should be relatively stable, but if the air temperature is swinging more than 10F consider getting a tub and placing the fermenter in a water bath.

I took a large cardboard box and lined it with foam insulation from lowes. The whole thing cost about $10 including the roll of duct tape. I put a frozen gallon water jug in there and its about 10 degrees cooler than room temperature and its pretty constant.