Cider vinegar

I use a lot of cider vinegar, for salad dressing, cooking and this year in making Shrub (cider vinegar and honey). Instead of buying, I will convert last year’s excess cider (from home grown apple and wild black berry) to vinegar. 
It is pretty easy, buy a vinegar mother, let it float in the jar of cider, as it is an aerobic conversion, cover the jar with a muslin cloth. Keep in a cool dark place and  wait for 3 months.