rewarming: To reheat, preheat your oven or air fryer to 400F. Dunk your loaf under your (running) faucet and get it wet. Place the loaf in the oven, covered as to not overbrown, and warm for 5-10 minutes.
storage: If you plan to wait to eat your baked. goods, please store in an airtight bag. Please freeze if you plan to wait more than a few days. Sourdoughs freeze and reheat beautifully!
"stale" bread: Most people think that bread goes stale because it dries out. It's the opposite!
The starches in bread crystallize when they absorb humidity from the air. These crystals are hard, and this is the first stage of stale-ing. Stale-ification? Anyway…when you heat the bread in the oven or a toaster, you're melting those crystallized starches and driving off the water that is required for them to reform.
Why run the crust under water before putting it in the oven, then? Because by the time the starches melt and are driven off in the center of the loaf, the crust will dry out excessively and likely burn. By wetting it, you're essentially delaying how long the crust is exposed to direct heat, which will help keep the crust crusty but not too crusty – so your bread will be warm and taste freshly baked.