True to its name, watermelon is almost 95 percent water. The fruit originated in West Africa and is a crucial source of water in arid regions. Capable of exceeding 100 pounds, most watermelons come to market at 10 to 15 pounds and are at their best during the summer.
Unlike their relatives the muskmelons, watermelons belong to a small, simple family. The choices are round or oblong, solid green or striped, with or without seeds. Watermelons have deep pink to bright red flesh that is crisp, juicy and sweet. Yellow and now orange-fleshed hybrids are sometimes available.
Look for a large, pale yellow (but not white, soft or moldy) patch on one side of the watermelon, indicating it was left on the vine to ripen and hence should be sweeter. For the juiciest ones, knock on the melon and listen for a deep resonance.
Refrigerate whole and cut watermelons because, after they are picked from the vine, their flesh becomes increasingly dry and fibrous in warm temperatures. Although best eaten as soon as possible, a whole watermelon can stay in the refrigerator for up to 1 week. If it is too big to fit in the refrigerator, store the melon in a cold, dark place for no more than 3 days. Cover cut pieces with plastic wrap or place in an airtight container.
Using a large, sharp knife, carefully cut the watermelon in half lengthwise or crosswise. Scrape out and discard the seeds. So-called seedless watermelons may have small white seeds; though they are edible, many cooks remove them before using in recipes.
Adapted from Williams-Sonoma Kitchen Companion: The A to Z Guide to Everyday Cooking, Equipment and Ingredients (Time-Life Books, 2000)