Another interesting one from the Oeconomia
However, there are many species and types of plums and there are cerasa, cherries, that you would also like to count among the plums propter similitudinem (on account of their similarity), there are pruna sylvestria, sloes, Virgilius calls the bushes on which they grow spinos. Schleedorn (spiny sloes) are a good thing if you use them properly because you make sloe wine from them.
In many places, they also preserve them around Michaelmas after the frost has struck them and they have turned soft. You take mustard and grind it with vinegar, and when it has been ground very fine, you put the ground mustard into a new pot and add the sloes whole. Let it stand thus for fourteen days, and then when you eat dried meat, fried pickled herring, ham, or other things from which you usually get scurvy, eat it along with them from a small condiment bowl (Commentichen). This helps, next God, that scurvy will leave you alone and it is good to eat.
This is interesting both because it could actually be good and because it casts a light on the practicalities of diet-as-medicine. People did not understand the origin of scurvy in vitamin C deficiency, but they knew the disease struck sailors at sea and Northern Europeans in winter – people who ate a lot of salted provisions and not much fresh fruit. The quest for a solution occupied many minds. Sloes are, of course, a good source of vitamin C, though it is doubtful how much would be left after this brute treatment.
Johann Coler’s Oeconomia ruralis et domestica was a popular book on the topic of managing a wealthy household. It is based largely on previous writings by Coler and first appeared between 1596 and 1601. Repeatedly reprinted for decades, it became one of the most influential early works of Hausväterliteratur. I am working from a 1645 edition.