Some time ago, I was muddling through my attempt at preparing one of the simplest dry cured sausage in Ruhlman's Charcuterie, saucisson sec. It's not fermented, just a simple mix of ground pork, garlic, salt and pepper and some curing salt.
I have a way of turning simple things into a 3 body problem. But, when I finish, I usually have a robust solution in which I know more about the process variables than if I nailed it on the first try. It's a frustrating way to learn, but learning is rarely uneventful.
The key environmental variables are 60°F, at least 60-70% relative humidity and some air movement. I won't rehash all the past attempts buried in my archives spent trying to find that environment. I will simply cut to the chase: I stuffed the sausage in beef casings and lay the links on a cooling rack suspended over some water in a plastic cooler in my basement. The open top of the high-walled container permitted air movement. The sides of the container coupled with the puddle of water in the bottom created a naturally bounded localized cloud of moisture that registered ca. 70% according to an accurate humidity probe and the temperature in my basement is about 60°F +/- 8°F almost all year 'round.
4 weeks of aging and voila. The sausage looks a little squat because it was on its side. So what. After I tasted it, didn't die, I fed it to others who enjoyed it immensely. The only changes? I didn't like the appearance of the wide beef middle casings - the biological reality of the appearance of these things is not pretty, I'm going back to simple small hog casings. And, I'll be using a finer grind. I like coarse for fresh sausage, it keeps them moist on cooking, but the dry cured, I believe, needs a finer grind.
A peek at the newest run (smaller casings, finer grind) about a week in: