It’s not the humidity, it’s the heat

As the weather turns cool and damp, articles suggesting that you need to adjust the amount of flour in your baking recipes start popping up on newsfeeds. Usually the author suggests that you may need to add more flour to a recipe to account for the extra humidity. However, the science of humidity and flour doesn’t mesh with this advice.

What the research suggests is that for most home bakers, the amount of water absorbed by flour after you have purchased it is negligible, no matter the weather. Most houses fall into a range of humidity levels that make it unlikely that your flour will pick up or lose a great deal more moisture than it already has acquired or lost sitting on the store shelf. With proper storage, it takes weeks or months for flour to absorb any significant amount of moisture from the atmosphere.

So why does dough sometimes seem stickier or drier as the weather changes? Temperature is one likely culprit. The amount of water that flour absorbs – or perhaps more accurately the rate of water absorption – depends on several factors, but chief among them is temperature. Instead of adding more water to the dough, you may want to consider changing the temperature of the water. The age of your flour and how it is stored can also be factors. As flour ages, the gluten proteins become oxidized, which can have both desirable and undesirable effects depending on the gluten characteristics of the flour.

Some ingredients are more hygroscopic (tending to absorb moisture from the air) than others. Sugar is one of those ingredients, which is why it’s difficult to keep crunchy meringues or crisp cookies from getting soggy when it’s humid. But that has to do with water absorption after baking rather than the ratio of recipe ingredients beforehand. With all of these variables at play, it is almost a miracle that baked goods turn out well at all. But even a not-quite-perfect homemade pie or loaf of bread is divine, so don’t sweat the small stuff.

Photo of Portuguese sweet bread from The Bread Baker’s Apprentice by Peter Reinhart