Right now I’m at my desk, melting into my chair. The first floor of our duplex apartment—which includes the kitchen and my office nook—is a long, entirely open space, which makes it inefficient to cool with air conditioning. Which makes baking bread a serious challenge when the temperatures are where they are right now (90˚F and climbing). (Hell, even writing about baking is pushing the limits of my abilities right now, which is why this newsletter is dropping later than usual.)
Looking at national meteorological maps, there aren’t many of us in North America who are being spared these unseasonably early and intense heatwaves. And we have nearly three months of summer to go still. So does this mean that we all need to put our bread baking on hold for the season?
I don’t think so, but you definitely need to have a set of strategies for dealing with how the heat is going to muck with your fermentations. As I’ve said before, the “ideal” temperatures for bread are between 75 and 78˚F (75 for yeasted breads and 78 for sourdoughs, but the difference is negligible enough not to worry about most of the time). Five degrees to either side of this window is generally manageable—since it doesn’t slow down or speed up the fermentation excessively (you’ll just need to adjust the timing of each stage a little). And temperatures well below that range are relatively easy to overcome if you have an enclosed space and a source of gentle heat (like a light bulb or pilot light in an off oven, or a heating mat and an insulated box).
Out of the Frying Pan
But cooling or slowing things down when temperatures are well above 83˚F are another story. I don’t have a definitive one-size-fits-all answer on how to deal with this kind of heat (aside from working in an air-conditioned space), but here are some strategies to consider:
Reducing the amount of levain (or yeast). Most bakers adjust the amount of levain in their sourdoughs seasonally, and most of my recipes give a range to use depending upon the time of year. With the no-knead recipe (Loaf 2.0), for example, my recommendation is to reduce the amount of levain to 1%, or 1/10th of what I’d use in the dead of winter. With temperatures as high as it they are now here, I’d probably even take that down to 0.5%.
Reduce the hydration. Many bakers also take down the hydration of the dough during the hot (and humid) months. Among other things, this does help slow fermentation. It also helps keep the dough texture consistent, since when the humidity rises, the dough becomes more wet. (I’m not sure if that’s because it absorbs more water from the atmosphere when humidity is high, or gives up more water when it is low.) You’ll have to experiment, but a reduction of 2 to 5% is not uncommon.
Reduce the temperature of the dough at the start of mixing. Using the DDT formula and cold water, you can set the temperature of the dough somewhat lower than you normally would, in order to slow down the fermentation. This only goes so far, however, since the dough is going to warm up during bulk fermentation until it equilibrates with ambient temperatures. And obviously if you start with a dough that is very cold, it could slow down fermentation excessively.
Do the bulk fermentation at night. This too only goes so far, especially since it takes so long for the air indoors to catch up to that out outdoors, but you can take advantage of naturally cooler nighttime temperatures to try to keep your doughs in a more reasonable zone. (Unless you want to pound coffee all night or are naturally a night owl, you’ll want to use a low-inoculation, long-fermentation recipe like The Loaf here.)
Place the dough in the fridge during the bulk fermentation. Not the entire time, because that would chill the dough excessively. But if you are doing a relatively short bulk fermentation (like with the Loaf Classic), you could try putting the dough into the fridge periodically—in between every other fold, for example—to push its temperature closer to the ideal zone. Exactly how long to leave it there will depend upon the amount of dough and ambient temperatures, so you’d want to set a timer and check its temperature regularly until you figure out a schedule that works for that particular dough. (A remote temperature probe with an alarm would be useful here.)
Proof it in an insulated cooler. If you start with a cold dough and maybe add a few ice packs, you can push the inside of a cooler into the safe temperature range, and it will stay there longer than the room it is in ever would. Again, you’ll have to monitor the temperature of the dough to make sure it stays in the right place.
Some combination of the above. The best approach to beating the heat is probably going to come from a mixture of strategies and is going to take some experimentation to figure out in your particular case.
Note that the above ideas mainly apply to how to manage bulk fermentation, since once you get the dough properly fermented, you should be taking advantage of the fact that you can put the shaped dough in the fridge to do the final fermentation, at which time the ambient temperatures in your kitchen don’t really matter. (Of course you could also proof the loaves at ambient temperatures, but I don’t recommend the hassle if you can easily avoid it.)
And Into the Oven
There’s not a lot you can do to avoid the need to turn your oven on if you want to bake bread, but there is one way to minimize the time the oven spends on during a heatwave: The Cold Start/Cold Oven method. I don’t use it very often myself nowadays, except in the summer, because I tend to bake in my Challenger bread pan1, which I believe is a little too massive to work with a cold start. But I used and recommend the method for years, and it definitely works with other vessels, including an enameled cast iron pot.
The method is simple:
You place the loaf on a piece of parchment that has been coated with nonstick spray or oil and score it.
You then place the scored bread in a cold pot, place the covered pot in a cold oven on the highest rack that will accommodate it, and turn the oven on to 425˚F.
You then bake it exactly as you would with a hot start, i.e., you cook it covered until it has fully sprung (about 30 minutes in this case), and then remove the lid and either move the bread to the bare oven rack or leave it in the pot and bake it until it is nicely browned.
This works because a) the initial oven spring and crust formation don’t necessarily need to happen quickly to work, and b) because the oven takes awhile to come to temperature, the bottom element is likely to be on for the first half of the bake, which means the pot actually heats up pretty rapidly. By the time the oven is hot enough to start browning the crust, the loaf will be fully sprung and fairly well steamed.
I think you get a slightly better crust and maybe a slightly taller loaf with a hot start, but the difference is negligible enough that using a cold start when it’s hot out is well worth the tradeoff.
Two important things to keep in mind with this method:
Because the element is on for much of the bake, the loaf can get dark on the bottom quickly (that’s the reason for the slightly reduced oven temperature here), so you might want to remove the loaf from the pot and bake it on the oven rack to prevent burning. And this is why you want to put the pot as high in the oven as it will fit comfortably, to move it away from the element.
Because the bottom crust forms slowly with this method, it will bond to the pot if not lined with parchment paper, and—if the parchment isn’t coated with oil or nonstick spray—to the parchment paper.
I know there are many of you who live in regions where these sorts of temperatures are more common. What are some of your strategies for baking bread when the thermometer starts to rise? Share them with us in the comments below.
I’m going to do a test of this myself soon, just to be sure.