Hydration in Cook's Illustrated sourdough recipe
(I would've asked the folks at Cook's Illustrated / America's Test Kitchen this question but I didn't see any way of doing so for a non-subscriber.)
I bought a copy of Cook's Illustrated All-Time Best Bread Recipes. Very good book, in general. But unless I'm doing my math wrong, their recipe for "24-Hour Sourdough" calls for a 57.6% hydration, which seems crazy low to me.
Here are the ingredients:
½ cup (4.5 oz.) starter*
6-8 tablespoons (3 - 4 oz.) water
1 cup (5 oz.) flour
Entire sponge, plus:
1½ cups water
4¾ cups (23.75 oz.) flour
2½ tsp. salt
Starter = *3 cups (24 oz.) water + 4½ cups (22.5 oz.) flour, i.e. 106.7% hydration
So for the final dough, I come up with:
Flour: 2.18 oz. (from the starter) + 5 oz. + 23.7 oz. = 30.93 oz. total
Water: 2.32 oz. (from the starter) + 3.5 oz. (assuming 7 tbsp. from the sponge) + 12 oz. = 17.82 oz. total
Which gives me 57.6% hydration.
Is that right? Isn't that way low? Am I missing something?