Fermentation temperature problems?

I recently brewed a batch of the Kama Citra Session IPA and it smells good and has a decent but thin taste to it, however when I took the FG of it and ran the numbers to get my ABV it was less than 2%. I am thinking that the temperature during fermentation caused it to drop out too early and not finish fermenting. I used the Safale US-05 yeast for it and usually have good results with it. I did recently move to a new apartment in WY and due to the heating costs of my stupid baseboard heaters we keep the temp set at 65 but the apt. is usually around 63 degrees. Has anyone else experienced problems like this and if so do you have any ideas for me? I am assuming that it was the temperature that caused my problems since we did everything the same way we always do and this is the first time I have had this problem. I would greatly appreciate any feedback on this.

I suspect you’re using a refractometer to measure your final gravity. The presence of alcohol skews the reading, and you need to plug your OG and current brix into a calculator to give you a “corrected” final gravity. I believe NB has one - type in “refractometer calculator” into the search box and you should get there.

If your yeast really had stalled at only 2% ABV, the beer would be cloyingly sweet.

Or I’m betting you did a partial boil (2gals) and then topped up to 5gal. When you added the water it wasn’t mixed thoroughly and you have what is known as wort stratification. When you take the reading the sample is significantly watered down, resulting in a very low OG. I note you didn’t mention OG or FG.

I recommend you put one of those cheap stick on thermometer strips onto your fermenter so you know for sure what the temp is. If your putting your Carboy in a closet on an outside wall it could end up being 10-15 degrees colder than the room. I worked around this problem by strapping a heating pad to it when it drops too low.