Just used regular lowfat buttermilk since that's what available here. This is so delicious and so easy. Lovely texture and flavor.
I made this sherbet along with three other flavors of homemade icecream for the ice cream social party I put on for neighbors on my block, and this flavor was the runaway favorite. Very refreshing. Just the right amount of tartness. Would make a good palate cleanser between courses of a fancy dinner.