We are about to make mead (we got near 30 pounds of local honey!). In researching mead-making, different yeasts have different alcohol tolerances … so you make a dry mead by using a yeast with an alcohol tolerance at or above the level your starting gravity would yield if it were fully fermented. A sweeter mead means you have a yeast whose tolerance is lower than that value … the greater the difference, the sweeter the mead. We are going to make a dry mead with Lalvin 71b-1122, a just slightly sweet mead by adding a little more honey but still using Lalvin 71b-1122, and a sweeter mead using Lalvin D-47.
71b-1122 has a very broad temperature range (59-86 F – and how cool is it that Google returns a yeast profile summary if you search for “71b-1122 temperature range”). D-47 is more particular — a published range of 59-68 F, but reading through homebrew sites has us wanting to stay around 63 degrees. Our sub-grade level is cool, but not that cool. Especially as fermentation warms up the fluid.
Scott is developing a home automation controlled fermentation “chamber”. The beer refrigerator is now plugged into a smart outlet. One of the Arduino kits we got has a temperature sensor. We can have a temperature probe monitoring the must and cycle the refrigerator’s power to keep it within a degree or two of our target.