Whether it's due to the inevitable heat of summer, the cumulative result of simmering a pot of stew all afternoon, or a holiday baking extravaganza, the kitchen has a way of warming up faster than any other room. Air may be a poor conductor of heat, as Kenji has explained before, but it can be mighty effective over time, slowly warming your kitchen by degrees. Room temperature is more than the air around you; it represents the temperature of your flour, your mixing bowl, your countertop, and your rolling pin, too.
Flipping on the A/C may help you feel better in the short term, but unless you crank it 24/7, it won't have a chance to cool your equipment and pantry staples. For example, we don't run the air-conditioning at Serious Eats over the weekend when no one's around. Blasting it on a summer morning cools the place down to 74°F (23°C), but plunging a thermometer into a bag of flour tells a different story.
This 78°F (26°C) flour is well below body temperature, making it feel cool to us, but it's a veritable heat source to a block of butter. That's a big deal for pie dough, because its texture depends entirely on butter. When that butter's nice and cold, the dough will feel as soft and supple as well-worn leather—not wet or sticky in the least. But when "room temperature" climbs above 73°F (23°C), everything that touches your dough will warm it on contact, softening the butter and making it sticky to the touch.
That's why pie dough seems to need less water on a hot summer day; soft butter functions more like a liquid than a solid in the dough. Folk wisdom says that humidity plays a role in how much water your dough needs, but I've gotta disagree. Flour has a fairly low capacity to absorb moisture from the air, and that very property is what keeps it stable on the shelf. If flour could suck up enough ambient moisture to change how a recipe behaves, it would mold as quickly as a loaf of supermarket bread.
Adapting to soft butter by using less water in the dough is generally a terrible idea. For starters, it makes it more difficult for gluten to form, producing a weaker dough that's more likely to stretch and tear. Weak doughs are also prone to slumping out of shape in the oven, and they crumble readily once baked. Not only that, such doughs are thirsty as well, eager to absorb moisture from a pie filling, making the crust soggy and pale.
When things heat up in the kitchen—say, anything above 73°F—the only viable solution is to focus on keeping the dough temperature below 70°F (21°C). That means taking a few steps to counteract the heat sources in your kitchen—and I'm not talking ice water or frozen butter, fixes that don't do anything to address the heat all around.
The first and easiest step is to toss everything in the fridge, from your bowl and rolling pin to the pie plate itself. (A warm-ish pie plate can soften the dough on contact, encouraging it to stick and making it more difficult to slice the finished pie.) You'll also want to refrigerate the "dry mix" (flour, sugar, salt) of your recipe, and the water, too, as the measuring cup itself may be warm enough to knock the chill off cold tap water.
The goal of this step isn't to get things frosty-cold, but to simulate the temperature of a slightly cooler kitchen so that the finished dough clocks in at somewhere between 65 and 70°F (18 and 21°C). Outright frozen ingredients are bad news, cooling the butter to the point at which it no longer has the plasticity to roll and fold within the dough, which will cause it to crack and crumble.
Keep It Chunky
If a recipe provides detailed instructions for handling a temperature-sensitive ingredient like butter, take heed! For example, my Old-Fashioned Flaky Pie Dough calls for two sticks of butter cut into half-inch cubes, each roughly smashed.
Those specific directions keep the pieces relatively large and thick, and therefore cold and firm. Cutting the butter into smaller pieces will increase the surface area, creating thinner pieces of butter that quickly turn sticky and soft. That's exponentially truer for butter that's rubbed or cut into a fine meal, which will also give the pie crust a crumbly, biscuit-like texture.
Ice, Ice Baby
If it's truly hot in the kitchen, your countertop itself is the enemy, a source of heat to every square inch of dough. Fortunately, there's an easy fix.
Divide several cups of ice between two gallon-size zip-top bags, add a little cold water to each, seal tight, and lay flat until the counter below is nice and cool. Again, you're not trying to turn your kitchen into a winter wonderland! You simply want a countertop that will be your ally in maintaining a dough temperature of between 65 and 70°F.
Know Your Dough
An instant-read digital thermometer makes it easy to identify ingredients that are too warm from the start, and it's a foolproof way to monitor the temperature of your dough. If it's particularly warm in your kitchen, aim to keep the dough around 65°F (18°F). Any colder and it won't behave as it should, making a digital thermometer especially helpful when you're softening doughs that have been made and refrigerated in advance.
When it comes time to roll, don't skimp on the flour. I'm not talking about a pinch or a sprinkle, but entire handfuls, tossed above and below. This will keep the dough from sticking as it's warmed and smashed between the counter and the pin. You can always dust away excess flour with a pastry brush, so don't be shy!
Remember, these steps are simply meant to counteract excessive heat in the kitchen, so you may not need them all. Just being aware of how the temperature of your ingredients and equipment can impact a dough will go a long way toward helping you avoid the frustration of wrangling a sticky mess. Keep the dough temperature between 65 and 70°F, and rolling it out will always be a breeze.