Alton Brown did this on his show. Heat up one gallon of skim milk to 120F. Pour in 3/4 cup white vinegar and stir a bit. Let it sit and cool a little. T he whey and casein will seperate from the water. Filter. I just did this and it came out looking almost like a lump of dough. Has a doughy consistancy and somewhat like mozarella cheese. Gonna try it later when it's cool and put some natural jelly on it. I guess it has like a gallon of milk's worth of protein. Either way, it's not bad.