Just in time for National Dessert Day on Friday, we've got humidity returning to the Coastal Bend. Humidity can mess up everything from your hair to your mood - baking is no exception.
I remember an angel food cake that my mom had baked was cooling, and it dropped onto the counter. She wasn't too happy about that.
My mom, grandma, and aunts are all avid bakers; I like to think I'm following in their footsteps. So when they say that you can't make divinity or peanut brittle and that dough rises differently when it's humid, it's worth a listen.
There's actually scientific truth to their claims. Humidity, temperature, and even air pressure can affect the baking process. Let's start with humidity.
HUMIDITY
Humidity is, by far, the component of the weather that has the biggest effect on baking.
What we're usually referring to when we talk about humidity is "relative humidity." This relates the amount of moisture in the air to the amount that would be present if the air were saturated, which depends on the temperature of the air.
Warmer air can hold more moisture than cooler air, so bakers often run into issues on hot and humid or rainy days.
Humidity - especially indoor humidity - dictates whether baked goods fall flat, are too dense, too dry, crumbly or chewy. Cakes can become super crumbly on the surface and become more difficult to frost as they cool down on a rainy day.
Humid air messes with your dry baking ingredients. Ingredients like flour, sugar, and baking powder are hygroscopic - meaning, they soak up the moisture from the surrounding air. This is how we end up with clumpy or caked sugar and flour.
Many ingredients perform their best when stored in cool, dry areas. This also helps extend their shelf life. You can store dry ingredients in the fridge or freezer, but you have to return them to room temperature before using them. If you don't, your doughs and batters may not rise properly.
It's also best to avoid meringues and divinity during muggy or wet weather. Sugar easily absorbs moisture in the air, which throws off the egg white-to-sugar balance. The unbalanced ratio keeps the mixture too soft, prevents you from achieving stiff peaks, and keeps it from setting.
The ideal relative humidity for baking is 40-60%, but some items do need higher humidity. Dough fermentation requires a relative humidity of at least 75%. So dough usually rises faster in a humid house.
There can be too much of a "good thing", though. Too soft or too sticky yeast dough is likely the result of hot and humid weather. Lower humidity generally results in a crustier, crunchier bread.
Even the humidity inside your oven can affect how your bread turns out - in multiple ways. If there's too much moisture, it obstructs heat transfer and makes your crust temperature too low, so you end up with a lighter-colored crust. Higher humidity inside your oven can also help your baked goods retain moisture and also allows the yeast to keep expanding the dough longer. It will also result in a glossier and thicker crust.
To combat high humidity, some websites suggest reducing the amount of liquid in your recipe by 1/4 cup; others suggest a 10-25% reduction.
TEMPERATURE
Some baked items actually require heat prior to the oven. Bread dough is placed in a warm, humid place (like a proofer) because yeast loves humidity and becomes more active, making the dough rise quicker. This also keeps the dough moist.
Proofing is sometimes called the "second rise." Proofing conditions for dough are hot and humid: 95-110°F with 80-85% humidity. I'll point out the obvious and say most of us don't intentionally maintain those conditions in our homes.
AIR PRESSURE
Lower air pressure has two main effects on doughs and baked goods. First, they rise more easily. If an area of pressure (like a cold front) is nearby, baked goods will act as if they're baked at a higher altitude where air pressure is lower. Less air pressure essentially means less resistance, allowing cakes and breads to rise more quickly.
Second, they lose moisture faster. Since water boils at lower temperatures at higher altitudes, liquids evaporate more quickly. At sea level, water boils and evaporates at 212°F. At 6,000 and 10,000 feet, water evaporates at 200°F and 194°F, respectively. This means that your baked goods can dry out quicker while baking when low pressure is nearby.
So next time you channel your inner Betty Crocker or Pillsbury Dough Boy, check the forecast first. It may just help you bake a little better.
