Currently brewing a heavy Cream ale, OG 1.065. US05 has been very busy in ambient low to mid 50s for 2 weeks now; fermenter shows very active with airlock burps every 5 to 9 seconds depending on current temperature at the time high krausen prominent to this day. Aroma from air lock pleasantly subtle. Considering this to be experimental. Any concerns or considerations?
That's kinda low for most ale yeasts, so a slower fermentation isn't really a surprise. The temperature in the fermenter was probably a few degrees warmer early on during active fermentation, but is probably pretty close to ambient by now. How much does the ambient temperature vary? Any way you can warm it up for a few days to make sure it's done?
Ambient has drifted up and down between 53 and 58. Visual activity seems fast in clear fermenter and airlock active at 5 to 9 second intervals. Krausen is 4 inches still. Can easily relocate but, waiting for signs of clearing; krausen fall.
If you're willing to just wait it out then that's certainly the easiest thing. Some people on the forum have claimed that US-05 is actually less clean if fermented at lower temperatures (e.g., peachy). YMMV of course.
Some peachy, others not. Going with my gut. Will let it ride for upto four weeks total. When activity begins to slow and krausen starts to fall I'll warm to 68° for 3 days. And then, we'll see what happens.
Will post results as I'm not seeing any mention of US05 in mid 50s.
US-05 is best at 64.4°F-78.8°F ... Curious to see how it goes for you outside the optimal range. I think it will still ferment, just slower.
You might try NovaLager - it will ferment , low 50s - 68°F as optimal range. It's a lager yeast, but a hybrid of some sort. I've used it and had great results in ale or lager style recipes.
That must be a very old package. And I think that ideal range is still wrong (should be 59-72, not 57). Fermentis changed their recommended ranges several years ago.
Of course that doesn't mean you can't ferment lower, but maybe they raised the low end of the range because people were complaining that a yeast marketed as being clean was throwing esters?