A ripe watermelon will take about 9 milliseconds to go through one cycle of oscillation. The equivalent vibration mode for Earth takes 54 minutes, but the principle is exactly the same. Helen Czerski, WSJ
Can You Really Tell If A Watermelon Is Ripe By Rapping On It?
I’ve always relied on the rapping sound. If it sings to me, it’s mine. Up to three at a time usually. I first look for the melons that have bee stings with sap bubbles. Then I look for the ones that look like they’re ready to burst. Not very scientific, but it works for me.
You probably don’t know this about me, but I have an uncanny super power when it comes to picking a ripe watermelon. (I can also delay Summer or extend it by when I decide to make the first or last melon purchase of the year, but that’s a story for another time. Ask my wife.)
When I find a candidate, I pick it up and cradle it in my palm, holding the melon next to my ear. Then I give it a knock with my knuckles. If the sound has a ring to it, I know it’s perfect.
I’ve never been wrong. It’s a gift. As I said. I’ll often buy three at a time and by the time I’m loaded, there’s usually one or two shoppers who either ask me how I pick, or they ask me to pick for them. It always takes me longer to buy watermelons than anything else. When I write the definitive ode to watermelons, I’ll make sure the book signings match the season. Buy the book, get a perfect watermelon.
It turns out that there’s actually science behind my super power. As soon as you learn the secret, you’ll begin to develop your own watermelon ring and never be disappointed again. One word of caution: Don’t go rapping on a pile of watermelons in a crate. You have to isolate the melon or the sound waves won’t give you accurate data. You’ll get lucky occasionally, buy mostly you’ll be disappointed and start blaming the watermelon.
The Science of a Ripe Watermelon
The first test for watermelon quality is whether it has an unwanted air gap inside it. When you tap on a nice, clean shape like a mug, what you hear is close to a pure note—the structure is symmetrical, and it rings like a bell. The same is true for watermelons. If you get a note with an identifiable pitch, the fruit is probably solid all the way through. A dull thud indicates that it’s asymmetrical on the inside, and best avoided.
The next question is ripeness. As watermelons ripen, their flesh becomes more dense but less elastic, and the combination means that a riper watermelon will ring with a lower note. What you hear also depends on how big the fruit is. There is no perfect note, but there is a perfect note for a fixed size of fruit. You need experience with lots of ripe watermelons to make the correct diagnosis, so this isn’t a quick fix. But not to worry, nobody said Jedi training was easy. Practice makes perfect.
Your Watermelon Nutritional I.Q.
Beyond the zillions of ways to serve watermelon, I’m old school. I rarely take the time to do anything else to a watermelon other than to cut a fat, full round slab, cut off the rind and savor the tastes as my belly starts go grow. Not recommended for before bedtime on hot Summer nights in Southern California. Watermelon has lots of wonderful nutritional benefits beyond that perfect, fresh, ripe taste. Note the serving size – 1 cup. Who’s kidding who here?
Watermelons are mostly water — about 92 percent — but this refreshing fruit is soaked with nutrients. Each juicy bite has significant levels of vitamins A, B6 and C, lots of lycopene, antioxidants and amino acids. There’s even a modest amount of potassium. Plus, this quintessential summer snack is fat-free, very low in sodium and has only 40 calories per cup. Learn more about the health benefits of watermelon.
Watermelon Care and Handling
Watermelon isn’t just for summer picnics anymore. This deliciously sweet fruit is available year-round. And it’s perfect for every meal occasion from breakfast, lunch, appetizer and entree to dessert. It’s healthy and nutritious, but most importantly it tastes great. It’s perfect for people who are trying to eat healthier, but don’t want to give up great taste – just about everybody!
Store Watermelon on the Warm Side Compared to most fruits, watermelons need a more “tropical” climate – a thermometer reading of 55˚ F is ideal. However, whole melons will keep for 7 to 10 days at room temperature. Store them too long, and they’ll lose flavor and texture.
Lower Temperatures Cause Chill Injury After two days at 32˚ F, watermelons develop an off-fl avor, become pitted and lose color. Freezing causes the rind to break down and produces a mealy, mushy texture. Once a melon is cut, it should be wrapped and stored at 36˚ – 39˚F.
Removing Seeds Is A Breeze Although a majority of the watermelons available are seedless, these instructions will remove seeds quickly and easily: Wash and quarter a whole melon, then cut each quarter into three or four wedges. Cut lengthwise along the seed line with a paring knife, and lift off piece. Using a fork, scrape seeds both from the removed piece and the remaining fl esh on the rind. Use for cubes or continue with recipe.
Safe Handling Practices According to the FDA, you should wash all fruits and vegetables, including all melons, in clean, running water before eating them. This is true of all fruits and vegetables, rinds or not. You should also use clean knives and cutting surfaces.
Additionally, persons preparing melons, fruits, vegetables or other foodstuffs should thoroughly wash their hands with soap and water prior to preparing the food for eating. That’s food handling 101.
Yield Wedges: The average watermelon yields about 90 6-ounce wedges, each 3/4 inch thick.
Cups: There are approximately 3.2 cups per pound, so the yield is approximately 11⁄2 two-cup servings per pound.
Yield by Percentage of Weight: 100% whole watermelon = 70% edible watermelon + 30% rind. For example, the average 20-pound watermelon yields 14 pounds of edible fruit, leaving 6 pounds of rind.
Availability Top quality watermelon is available 12 months out of the year in today’s global market, and is especially plentiful during the peak season of April through October.
Creative Ideas and lots of great recipes, garnishing tips and carving ideas at www.watermelon.org