Sourdough Starter With Fresh Grapes (jvb)

Take a generous handful of grapes and crush them slightly. Place in
non-metallic container with an equivalent amount of both flour and
water.

Let it sit covered with a loose cloth on the counter checking two or
three times a day for signs it is beginning to work. (Can take as
little as one day or as long as five.)

When it begins to ferment, strain out the grape pulp. Feed with equal
parts flour and water to the desired quantity. Let stand loosely
covered at room temperature until ready to use (generally overnight).