X 2You don't need to add any ACV to your existing FF--just more feed and water.
To make ACV, Galanie's recipe is to use 2 cans of plain frozen apple juice reconstituted with water. Add room temperature apple juice to a gallon jug, mix in 16 ounces of Bragg's ACV. Place coffee filter on top of jug with a rubber band, put it in a dark place, and wait at least 1 month to see the "mother" on top. You can re-use this mother to make more with additional apple juice. I have also made it from apple peelings and cores from making pies.
I have used Galanie's recipe and now have three gallons of homemade Un-ACV in reserve at any one time. I like to hold the jugs up to the light and marvel at the big glob of suspended 'mother' floating in it.
