Concern about large temp drop

[jas0n]

i'm brewing a Scottish 70/- from Brewing Classic Styles and pitched Wyeast 1728 about 5 days ago. I put the carboy in my basement, which had been a steady 65 F, and fermentation was pretty active from day 2 to 4. Then my furnace went out, and over the course of 4 to 8 hours the temperature dropped about 7 degrees to 58 F. I got the furnace fixed and the temperature back up to 62. where it's stood for about a day.

Fearing 62 would be too cold, I brought the carboy upstairs and where its 65-66. I'm not getting the vigorous activity I was seeing before. But I'm still seeing bubbles stream to the top and modest bubbling in the air lock.

My question is, should I do anything else at this point or just leave it alone and see how it goes?

[brewerTristan]

Fermentation was very likely mostly finished by day 4, before your temp went down, so you should be okay. Another thing to think about is that if your ambient temperature was 65, then your fermentation temp was likely a bit higher. So even with the temp drop to 58, the temperature of the ferment was probably higher. What yeast were you using? Something like Cal ale is probably fine in those low temps.

Edit: sorry I see you mentioned the yeast you used -- wyeast 1728. Never used that yeast.

[animaldoc]

Check the gravity. I'd bet you're done fermenting. The little bit of "activity" you are seeing is probably just some CO2 outgassing because you are at a higher temperature and the CO2 is less soluble than at 58F.

So, what if you're not done fermenting? Swirl the carboy and rouse the yeast. Had to do that with a highly flocculant ale yeast that stopped at 1.023 -- within 3 days it was done at 1.012.

If that doesn't work, get an active starter going and add it at high krausen.

If that doesn't work, you *were* done and it wasn't going any lower anyway

[jas0n]

I checked the gravity this evening and it was down to 1.015, so it's pretty much done. I tasted the sample I took and it was pretty clean. It didn't have any off flavors I detected so I guess the beer's no worse for wear.

[Bugeater]

You will be fine. One effect of low temp fermentation of that yeast (one of my favorites) is that it will throw some slight smoky esters. It is these esters that lead some folks to make the blasphemous mistake of adding peat smoked malt to their scottish beers, not realizing it is the yeast and not the malts that give that characteristic flavor.

Wayne

[jas0n]

You will be fine. One effect of low temp fermentation of that yeast (one of my favorites) is that it will throw some slight smoky esters. It is these esters that lead some folks to make the blasphemous mistake of adding peat smoked malt to their scottish beers, not realizing it is the yeast and not the malts that give that characteristic flavor.

Count me among the blasphemers because I added, at the suggestion of the guy who owns the home brew shop I went to, 0.5 oz of smoked malt to my recipe. The beer is definitely smoky, a bit too much actually for my taste, though still quite drinkable. Lesson learned.