I have a slightly modded version of Ed's Haus Ale in primary right now. Through the most active few days it was fermenting at 64*F, but as activity decreased it has dropped to 61*F and may drop further because the basement closet where I ferment is a pretty cool spot (usually around 55 ambient, but warming up a little as outside temps increase). My question is this: do I need to worry about Nottingham yeast producing diacetyl at these temps, and would you raise it for a few days diacetyl rest or just let it mellow a bit longer?
I know 64 is close to what people often use for a rest, but 59 is a bit low and I am not used to fermenting this cool. I therefore don't know if I should expect diacetyl from cooler temps later in primary and Danstar's data sheet for Notty doesn't even mention diacetyl.