How to Soften Stale Bread

A sliced whole wheat baguette

Katrin Ray Shumakov / Getty Images 

There's nothing quite as tantalizing as a loaf of bread fresh from the oven. But nothing stays fresh forever. Over the course of a few days, that fresh loaf of bread gradually becomes dry and hard. And we have a word for that: stale. But is there anything you can do to soften stale bread?

Why Does Bread Go Stale?

Bread contains starch, and that starch is made up of two kinds of molecules: amylose and amylopectin. In their natural state, these starch molecules have a crystalline structure. When heated using dry heat, like when you toast a slice of bread, these starches undergo dextrification—the starches turn brown and turn to sugar. 

Caramelization is something different, but related, and happens simultaneously, having to do with the oxidation of sugars. It also results in the browning of bread. But with caramelization, it's a chemical reaction happening to sugars, whereas, with dextrification, it's the starch that is being acted upon. 

The Science of Starches

In any case, there is another characteristic of starches, which is that when they're heated using moist heat, they absorb water, causing the starch granules to swell. And, once you take the loaf out of the oven, the starches start to cool, and they gelatinize or thicken. This is what gives fresh bread its springy, spongy texture.

But over time, the starches undergo what is called retrogradation, meaning the starch granules give back some of their water, as it works its way to the surface of the loaf and evaporates. As this happens, the starches partially revert to their crystalline structure, which causes the bread to become hard and brittle. But fortunately, this process can be reversed—at least temporarily.

That's because there is still some water left in the bread. The trick is to heat the bread up so that water can be reabsorbed into the starch granules once again so it can revert to its springy, fresh-bread state.

Now, if you have sliced bread you want to do this too. You can simply pop it into the toaster for a few seconds.

But what if you have a whole loaf, and it's really hard? Like a baguette or batard?

How to Soften Stale Bread

To soften a stale loaf of bread, you need to heat it so that the starches will reabsorb the water. The thing to know is that this reabsorption starts to happen at about 131 F and continues up to around 185 F. 

The point is, you need a relatively low temperature to do it properly. If you try to microwave your bread, you'll likely get it too hot, the starch granules will burst, and the water will cook away in the form of steam, leaving your bread soft for about 30 seconds before quickly becoming even more brittle than before. 

The key is to warm it up slowly. Here's how:

  1. Preheat your oven to 300 F.
  2. Wrap your bread tightly in foil to keep as much water in as possible. If your bread is especially hard, brush the outside with water before wrapping it.
  3. Then, heat it on the center rack of your oven for about 30 minutes for a whole loaf; or 15 to 20 minutes for a partial loaf, or if you have a long, skinny loaf like a baguette. 
  4. Now, unwrap the bread and return it to the oven for another 5 minutes if you want a crispy crust, otherwise, go ahead and slice it up. You'll have warm, fresh, soft bread—at least until it cools and undergoes retrogradation once again in an hour or two.

But there's no real reason you can't repeat this process. The more times you do it, the less water there will be in the bread, and the less effective it will be. 

But it's worth a try. The worst that will happen is that it won't work. In which case, you can always make your stale bread into croutons: Dice it with a serrated knife, toss the cubes in a bit of olive oil, and bake them on a sheet pan for a few minutes until they're slightly toasted. Or, simply grind the stale bread up in the food processor to make breadcrumbs.