1 c  Skim milk
3 tb Plain yogurt
1 c  All-purpose flour

Fill a 3 to 6-cup glass, ceramic, plastic, or stainless steel container
with hot water and let stand. In a pan, heat skim melk to 90 to 100 degrees
on a thermometer. Remove from heat and stir in yogurt. Drain water from
warmed container, wipe dry, and pour in milk mixture. Cover tightly; if
using a screw-top jar with a metal lid, place a double layer of plastic
wrap over mouth of jar before screwing on lid. Let stand in a warm place.
After 18 to 24 hours, starter should be about the consistency of yogurt – a
curd forms and mixture doesnt flow readily when container is slightly
tilted (it may also form smaller curds suspended in clear liquid). If some
clear liquid has risen to top of milk during this time, simply stir it back
in. However, if liquid has turned light pink, milk is beginning to break
down; discard and start again. After curd has formed, gradually stir the
flour into starter until smooth. Cover tightly and let stand in a warm
place (80 to 90 degrees) until mixture is full of bubbles and has a good
sour smell (2 to 5 days). If clear liquid forms during this time, stir it
back into starter. If liquid is pink, spoon out & discard all but ¼ cup
starter; then blend in a mixture of 1 cup each warm skim milk or low-fat
milk (90 to 100 degrees) and flour. Cover tightly and let stand again in a
warm place until bubbly and sour smelling. To store, cover and refrigerate.
Makes about 1½ cups.
NOTES : ***WARNING*** I have never tried this recipe 🙂