So, long story short, I had a raging 2L starter that, during the course of brewing, appeared to take a nap shortly before pitching, from lots of bubbles and life to stillness. I have a stir plate and have successfully made starters numerous times. I thought this was odd. The starter was sitting in the room where we ferment, and the temperature is probably a bit cool for 3725, 66F, and 70-90F are the listed range. After the starter took a nap, I thought my partner was going to keep a heater in the room for a planned warmer fermentation, but he didn't. OG was 1.089 in a strong golden ale. The plan is to leave this beer in the primary for 4 weeks and check the SG, then decide whether to secondary or bottle. My expectations for FG are sub 1.010 with this yeast. We pitched, had 3 days of strong fermentation that slowed down predictably. This was 17 days ago. We also made a small beer at the same time and pitched some of the 3725 and the dregs of a Chimay White. We added a little DME to the small beer for OG 1.064. We went to bottle this beer yesterday and the SG is 1.044. I was stunned. We checked the temp of the beer and it was 78F, which is when we realized the thermometer had broken. It's randomly +/-10F. (I need an infrared thermometer). We wrapped the big carboy in a padded space blanket and moved both carboys upstairs where the temps are warmer. The big carboy was showing regular action, burps every 40 seconds or so. I'm not going to check the large beer for another two weeks, but I'm wondering what to expect. I'm curious about the following: If a slightly colder temp would shut the yeast down so much. The way the starter just stopped bubbling is weird, and I can't account for any other reason. Has anyone else had this happen? Because the initial fermentation was very strong, is it possible that the temps raised due to the bioactivity, then dropped too far as it slowed? If the fermentation picks up as the temperature raises, what effects could this have on the flavor profiles? Did I screw up something obvious? I live in Europe where people heat the houses a bit less than in the States, and though we successfully fermented in this room through the winter, once the heat got turned off, I guess it got a touch too cool in the spring. Lesson learned. Am I missing something else?
Oh yeah, and is it likely that the fermentation could have stuck on only one of the two carboys? I neglected to mention that the small beer is in a 5L carboy. We do this just to mess around and use excess runoff. Anyway, this may be my biggest question. Any sleuths out there who can help?
hmm...i fermented 3725 at about 65-70F ambient and it always finished about in the 1.000 range for 1050-1070 OG beers. So the small beer finished at 1044? I would definitely check the golden ale to see where it has finished. If for some reason it fermented to completion, you will probably want to re-pitch some yeast from that fermenter.
The cool temps could have stalled the fermentation (or more likely just slowed it down). I have never used 3725, but I bet if you keep it in its recommended range, it will finish just fine.
I love this yeast. Never have let it drop too low, but I would wager a good rousing and warming will get it going again.
