One of my favorite fermentations is yogurt making, and I’ve been making my own since 2005. For years I have been using commercial yogurt cultures as starters, and have had to replenish them every few generations. In your book you mentioned the heirloom yogurt cultures, which intrigued me. Unfortunately, the commercial sources of heirloom yogurt cultures do not ship to Israel, where I live. Nor do I know anyone who has an heirloom yogurt culture here in Israel. Therefore, it was with great interest that I read the chapter [in The Art of Fermentation] about plant origins of yogurt.