This idea came to me last night. It would be interesting to get the tang from fermentation which is more multi dimensional than adding vinegar etc. I'm cooking a duck tomorrow so I'm doing a proof of concept of sorts. I took a half pint mason jar of Kim chi I made in the fall and mixed it with about 1/3 of a quart of tomato sauce we canned and let it sit overnight. I'll add some honey ,tamari ,and spices and run it through the processor and marinade the duck with some of it overnight then roast it tomorrow and serve the rest of the sauce with it.