NPR News

Watermelon Confidential: Dessert And So Much More

NPR | By Susan Russo

Published July 9, 2008 at 12:31 AM EDT

I've already heard it this year. Have you? Thump. Thump. Thump. It's the thumping of watermelons.

You'd better get used to hearing it, since July and August are the peak months of a long watermelon season that runs from May to October.

Watermelon is big in the U.S. In 2006, $434 million worth of it was sold here. Though 44 states grow them, nearly all watermelons — 4.29 billion pounds' worth in 2007 — are grown in Florida, California, Texas, Georgia and Arizona. It's all about supply and demand — the average American eats more than 16 pounds of the fruit every year.

Considered primarily a dessert fruit, most people eat watermelon plain, which is a shame since it has great potential to enliven savory dishes. The key is to balance the fruit's sweetness with something salty, bitter, acidic or spicy. That's why watermelon is delicious when paired with salty cheeses, bitter salad greens, acidic vinegars and spicy seasonings such as hot curry powder. It's also a refreshing complement to smoky-flavored grilled meats and seafood.

First you need to know how to select a watermelon, which is where the thumping comes in. What is the point of thumping a watermelon? I didn't know the answer, so I decided to do some investigative reporting. Here's what I discovered: People sure do have a lot of opinions on why we thump watermelons.

I approached a well-dressed elderly couple looking at some watermelons at the farmers market and asked, "Why do you slap a watermelon before choosing one?"

Husband: "Because you have to hear the thud. Whack it hard with the palm of your hand, and listen for a good thud."

Wife: "It's more of a fump."

Husband: "A fump? What's a fump?"

Wife: "Oh, what difference does it make? As long as it makes some kind of sound."

Husband: "Well, of course it has to make some sound; you're whacking it."

I decided to move on.

I spotted a middle-aged, burly man slapping his way through a whole bin of watermelons. When I asked what he was listening for, he said, "Well, it has to be solid when you hit it. That's what you want — a solid feeling."

Then a young woman with oversized dark sunglasses walked up and said, "Um, sorry to interrupt, but you actually need to listen for a hollow sound."

I could feel my Pulitzer slipping away.

I decided to go to the farmers directly. Some said to listen for a thud. Others said a hollow, resonant sound. Some shrugged their shoulders and admitted they just didn't know.

Ugh.

I did learn how to select a watermelon, though. Look for a firm, symmetrical melon that is free from bruises, cuts or dents. It should have a healthy sheen and scratch marks on the rind, which are from bees that have pollinated the fruit. Pick up the melon to make sure it's heavy for its size (watermelons are 92 percent water), then turn it over to look for a creamy yellow spot where it ripened in the sun. I found no definitive guidelines on thumping.

I wonder if ancient people thumped their watermelons. Wall paintings in Egypt depicting large green fruits suggest that Egyptians were the first people to cultivate and eat watermelon 5,000 years ago.

Watermelon is the fruit of the African vine citrullus lanatus and is in the same plant family as cantaloupe, pumpkin and squash. The earliest wild watermelons were actually smaller and bitter tasting, unlike the sweet melons we enjoy today.

Merchant ships enabled the transport of watermelon along the Mediterranean Sea and to regions as far east as China by the 10th century. By the 13th century, the Moors, who invaded Spain, had introduced watermelon to Europe.

Watermelon was brought to the United States by African slaves and European colonists in the early 17th century. Thereafter, both colonists and Native Americans grew watermelons, which eventually led to bigger, sweeter melons as well as different varieties.

Today, numerous types of watermelons are grown, varying in size, shape, rind pattern, flesh color (including deep red, pink, yellow and orange) and even seeds.

Though seedless watermelons were developed in the 1950s, they did not become popular until about 1990, which coincided with their arrival in most major supermarkets. Today, seedless watermelons are valued for both their flavor and their convenience. Keep in mind that although seedless watermelons do not contain the typical hard, black seeds, they do contain some soft, edible white seeds.

If you're choosing a watermelon and you have an irresistible urge to thump one, listen for "a solid resonance." That, according to gastronome extraordinaire Harold McGee, indicates ripeness. Now, if I could only figure out what he means by a solid resonance.