It so happens I am conducting a diacetyl rest (on a rye lager), and I am not in control of the environmental temperature. That is, it has to rest in the garage, and temps have not been high enough to bring the wort temperature quickly to 60˚F where I would like it to be for 24-48 hours. It has only gotten up to 54˚F from its ferment temp of 50˚F. It's bubbling more, and the point is a brief period increased activity to shorten lagering times, so I guess it will be okay to just do the rest for a longer time, but how long?
Does anyone know of a chart or table that indicates how long diacetyl rests should optimally be at temps other than 60˚F?