For bread made without preservatives, my whole wheat sourdough bread will last surprisingly well − for days if it lasts that long. The bread is best a day after its bake, and is good if consumed within three days thereafter.
I often bake two or four loaves at once and store a few in the freezer for later use or some unforeseeable occasion. Otherwise, I keep my fresh loaves wrapped in a linen bag inside a breadbox. That only slightly airy storage will prevent mold from forming, and the sourdough’s crust will help prevent the bread from drying out too soon.
Some folks prefer to slice their bread sooner rather than later and keep it wrapped in a plastic bag or foil in the refrigerator for convenience, especially if they plan on toasting slices anyway.
Dampen the entire crust lightly with a watery mist. Place the loaf for 5 to 10 minutes, depending on the size of the loaf, in an oven that is preheated to 350° F. This should work once, but perhaps not twice with the same loaf.
However, refrain from microwaving leftover bread as it will become rubbery. Toast it instead.
As said before, I store some of my fresh bakes in the freezer, but only after they have cooled down to ambient room temperatures over typically some 4 hours. Sourdoughs made from only flour, salt, and water − without dairy or eggs, etc., hold up extremely well in a frozen environment. I even recommend slicing bread in halves before freezing the halves so one can thaw just as much or as little as one needs.
I wrap loaves tightly in foil and place them in an airtight, resealable plastic or freezer bag − for up to two months. I squeeze out as much air as possible before sealing the bag. Bread is unlikely to spoil in the freezer. Naturally, I have experienced a loss of quality over time, depending on the bread’s moisture content and how fresh the bread is before going into the freezer.
The main issue to avoid is freezer burn. It is generally caused by food not being securely wrapped in air-tight packaging while stored over longer periods of time. If large ice crystals develop inside the plastic or foil, the texture or taste of the bread may be compromised. Should the bread start to smell like other items in your freezer during the thawing process—or become crumbly or breaking apart—it likely is past its prime.
Thaw the bread in foil and plastic bag (to keep natural moisture in) at room temperature until it is no longer cold. Dampen the crust with a little watery mist and bake at 350° F for 8 minutes, depending on the size of the loaf. This should work at least once to bring the bread back to feel and taste next to freshly baked.
If defrosting slices, as opposed to an entire or partial loaf, pop them into a toaster after they reach a normal temperature. As with other foods, avoid refreezing bread to avoid further changes in texture and taste.
Preheated oven to 350° F, remove unthawed bread from the plastic bag, and bake in foil for 15 to 30 minutes, depending on the size of the loaf.