I've been baking decent bread for quite a while now, but I've run into this problem twice in a row, so thought I'd better figure out what I'm doing wrong. Until recently, I never used the sponge method to start breads, but I got a copy of Rose Levy Berenbaum's The Bread Bible for Christmas, and have been doing so since. The first time, I didn't have time to let it go overnight, so I just let the sponge sit out on the counter for a few hours, made the bread, and all turned out well. (It was the Cinnamon Raisin Bread recipe. Fabulous stuff.)
The second time, I let the sponge go overnight in the fridge (which is what she recommends for best flavor development), took it out the next morning, and put the rest of the dough together. It was almost impossible to work with; the moisture didn't distribute evenly, even after resting for 20 minutes or so, and it was impossible to knead. I had to let it warm up for a few hours before I could do anything with it. After I did, though, it turned out fine.
Today, I'm trying Alton Brown's plain white bread recipe from this week's Good Eats, and he, too, tells you to do the sponge in the fridge overnight, so I did. Took it out this morning and threw the rest of the stuff together, and the results were the same. Blobby, dry in some areas, wet in others, and impossible to work by hand or in my Kitchenaid. I waited an hour or so again, and it seems to be behaving now, but I'm curious.
Should I be letting the sponge warm up to room temperature before using it? It's really convenient to do the overnight thing, but not if I have to wait hours for everything to warm up so I can work with it. I've followed the recipe exactly, so I don't think I've made any other glaring errors.