When marinating meat for Russian "Shashlik"(BBQ) some people marinate meat in alcohol. My uncle prefers to use beer when preparing pork. My Georgian(this Georgia) friend uses red wine, which was the only ingridient I was able to get out of him. His BBQ is always very juicy and tender.
My questions: What types of alcohols should be used to help bring out meat flavor and making it tender without messing with the taste? Is there one type of alcohol that works great with all meats or should different types be used for different meats?
Bonus: What properties does alcohol possess that it makes meat tender?