The dry canyon air and the skin problem, fixed with a damp towel
Short lesson today, but it fixes something that trips up nearly everybody who bakes up here for the first time.
The problem. You mix your dough, you set it out to rise, and an hour later the top of it looks off. Dry. Kind of leathery, like a thin skin formed over the surface. You poke it and it doesn't spring back right. Then when you fold it in, that skin gets balled up into the dough and you end up with dry little streaks running through your loaf. People often blame the starter or the flour. It's neither. It's an air problem.
Our air up here is dry. Really dry. That's just elevation and geography, and it's worse in winter when the heat's running in the house. Dough is mostly water sitting exposed to that air, so the surface starts losing moisture the second you stop touching it. At sea level, in a more humid kitchen, this barely registers. Up here it happens fast enough that you'll see it inside an hour.
It took me embarrassingly long to figure this out. I blamed the flour, blamed Herb, blamed everything except the actual dry air sitting right there in my kitchen. Once I understood what was happening, the fix was almost insultingly simple.
The fix
Cover your dough while it rises. That's the lesson, really, but let me lay out the actual options, since "cover it" means different things to different people.
A damp towel. This is what I use most of the time. Wet a clean kitchen towel, wring it out so it's not dripping, and lay it right over the bowl or the container. The dampness in the towel keeps the air right above your dough from pulling moisture out of it. That's the whole mechanism.
A lid. If your bowl has a lid, or you're using a container with one, that works too. Same idea, you're just trapping the moisture instead of adding a little back in.
Plastic wrap or a shower cap thing, if that's what you've got. I don't bother with this myself, mostly because I resent finding a use for one more piece of plastic wrap, but it works fine if it's what's on hand.
I'd lean damp towel over the others. It's reusable, it's free, and it does a slightly better job in a really dry house because you're actively adding humidity, not just blocking air movement. A preference, not a rule. Use what you've got.
What to watch for
If you forget to cover it, or the towel dried out because your house is that dry, you'll see it: a matte, slightly tough-looking surface instead of a smooth, slightly shiny one. Press it gently. Good dough surface gives a little and looks moist. Skinned-over dough feels tight and almost papery.
If it's already happened, don't panic. Fold that skin into the dough during your next stretch and fold, same as you would anything else. It might leave a faint streak in the final loaf, but it's not going to hurt anything structurally. Cosmetic more than anything. Mildly annoying, not a disaster. Sourdough is forgiving, not fussy. It's flour and water sitting out, not a science experiment that punishes you for one mistake.
The bigger deal is during bulk fermentation, when your dough is out the longest. That's when you've got hours for the air to work on it, versus the shorter rest during, say, autolyse. So especially during bulk, get something over that bowl.
A Saturday, if it helps
I've mentioned my kids don't always get worked up about the bread thing. Elias especially — he's fifteen, he's on his phone, and as far as he's concerned bread is a thing that appears on the counter. But one Saturday I'd covered a bulk dough with a damp towel, gone to run an errand, and come back to a bone-dry towel and a loaf with faint dry lines through it. Elias ate almost the whole thing anyway, standing right at the counter, and said not a word about the streaks. I didn't make a big deal out of it either. But I did start checking my towel halfway through a long rise after that, especially in winter, when the furnace is drying the whole house out on top of the canyon air already doing it.
A couple practical notes
- Re-wet your towel if you're doing a long bulk ferment, especially in winter. It will dry out before your dough is done rising.
- Don't use a bone-dry towel and call it covered. It needs actual moisture in it to do anything.
- This matters more in winter than summer, and more in a heated house than you'd think. A humidifier running nearby helps too, if you've got one going for other reasons.
Before next time
Cover whatever you're rising this week with a damp towel and actually check on it once mid-rise. See if you can catch the surface starting to skin before it fully sets in.
- J