1 gal. milk
1 pkg. Knox gelatin
1/4 c. boiling water
3 to 4 tbsp. plain storebought yogurt

Heat milk in large pot until very warm, yet not scalding hot, because it will kill yogurt culture. Dissolve gelatin in boiling water. Cool and add to warm milk. Mix yogurt in small amount of milk and add to pot of milk. Pour into pint (or peanut butter) jars. Put closed jars in two big pots of very hot water. Set in oven (gas oven with pilot light) or other warm place to incubate for about five hours until set. Refrigerate for weeks. Delicious plain yogurt.