The recipe I have calls for it, but since Tom Lehmann set me straight on it.
I am wondering whether it will change my flavor at all, and whether I should just omit the quart of milk, and just add another quart of water.
The quart of buttermilk I use accounts for about .25% of my food cost (1/4 of 1%) which seems insignificant, but times that times $300,000 per store times 4 stores, and suddenly it still seems insignificant, albeits still $3000. a year.
I imagine I will make a batch next week, and have a taste test.