Are carbohydrates the greatest of the macromolecules? Probably. There's nothing quite like sinking your teeth into a doughy and delicious piece of steaming bread. That makes it all the more devastating when carbs go bad — when a piece of bread turns rock-hard and chips that once were crunchy get that gross, chewy texture.
But why do these starchy snacks age in opposite directions, one getting inedibly dry while the other goes soggy, and how can you get them back to their optimal texture?
The latest video from the American Chemical Society's Reactions series has some answers.
The situation boils down to this: Bread goes stale because it's lost too much moisture. Chips go stale because they've gained too much moisture. That's because chips lose most of the moisture inside them during the frying process, creating a crunchy network of starch molecules. Those molecules are hydrophilic, meaning they attract water from the air around them.
Now let's take a look inside bread. When bakers add yeast to dough and let it rise, they're feeding the warm, delicious sugars in the recipe to a colony of hungry, hungry fungi. Those fungi chow down and release carbon dioxide as a waste product, which fills the dough with tiny air pockets. That makes the dough bigger, because the air takes up space, but it also creates the chewy, moisture-holding structure we expect from our bread products.
But even though bread is designed to keep water in, the same hydrophilic process that turns chips soggy helps to turn bread into a crunchy nightmare. The drier parts of the bread — the crust — steal water from the chewy center. As the starch molecules that keep moisture trapped inside bread break down over time, it becomes harder and harder for the loaf to hold onto water. This molecular restructuring can be stalled by sticking bread in the freezer. In the fridge, it actually happens faster.
So what can you do to make hard bread soft and soggy chips crisp?
It's easy: Just take care of the moisture situation. For chips, this is as simple as popping them into the microwave or the oven for a couple of minutes. Drying them out will bring back their crunch. We can't promise a quick nuke will make truly ancient potato chips taste like new, but you can certainly use this trick to give slightly soggy chips a second chance.
The American Chemical Society recommends popping bread into the oven to help it absorb more moisture. We'd take that a step further: Get the bread wet first. Seriously. We're not saying you should take your baguettes into the bathtub with you, but running the crusty portion of your stale bread under a faucet can do wonders. Once you've moistened the loaf, stick it in the oven for a few minutes and watch it magically turn chewy and delicious once more.
For a quicker fix, you can wrap your bread in a wet paper towel and throw it in the microwave. If you've got a bag full of sliced bread and you don't want to have to moisten and heat up every single piece, stick a piece of celery in the plastic packaging overnight. The bread will leach water from the celery stalk, leaving a chewy loaf and a desiccated vegetable husk in the morning.
There you have it. Go forth and carbo load in good health.