American video about how you can make red wine vinegar. Personal experience shows that it can be simpler to pour leftover wine in a clean container and cover it with a lose stop (or as shown here with a clean cloth) and then wait until the wine changes spontaneously in vinegar. This can take a few weeks. The container should not be too cold: a warm storage room is ideal, or you can put the container on top of the basement stairs. Wild bacteria can sometimes give a bad result, but then you just start again. You smell it soon enough. Once you have a good vinegar strain going, you can always top it up with new left over wine to make fresh red wine vinegar. Do not pour too much fresh wine fresh in one go, because it can kill the vinegar bacteria.