Attenuation and Temperature

If the optimal temp for my yeast strain was 64°-75°, would being at the very lower end of that temp range, or even slightly lower affect attenuation? My EPA is done fermenting, and I calculated my attenuation to be 67.3% when the attenuation range for the strain I used is 68-72. Generally, this time of year is warm in SC, but we had an unexpected cold snap causing the temp inside to drop about 7 degrees (bottomed out around 60) toward the last day and a half of primary ferm. I know other factors also affect attenuation but I wanted to see how much temp does. By the way, looks like I might have an under-estery brew this time...

captaineriv
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Maybe the fermentation stalled at the very end because of the low temperature. Most of the vigorous bubbling had stopped by the time it got cold anyway. Plus, it was a pretty big drop in just about 12 hours time. Who knows, it could have gotten as low as 59 in that room. That area in my house is open and hard to heat when it's cold, but it's also the most practical place to ferment as far as ease of bottling, racking, sanitizing, etc, so it's kind of a catch 22. It just caught me off guard because it usually does not get that cold this late in the year here. The beer tasted relatively normal (at least like it should at this stage). I'm not too worried about it this time around. The strain (1099) is a lower attenuation strain (68-72%) and I was barely under 68%. I was just trying to prevent this sort of thing in the future.

captaineriv
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When I took the hydro reading yesterday, all activity in the airlock had been completely ceased for about a day and the floating piece was no longer rasied. Absolutely no activity in the airlock. Well, apparently the yeast warmed up and got hungry again. It's been over 24 hours since I took the SG and sealed it back up, and now I'm getting a bubble once every 5 seconds or so. I had planned to leave well enough alone, but if it wants to start fermenting some more, I won't complain.

captaineriv
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