Have you stood in a supermarket and watched people knock on watermelons?
Are you a professional 'watermelon tapper' yourself?
Essentially, the tapping technique is all about what sound it makes.
If you thump it with your knuckles and it makes a nice, deep "plunk" sound instead of a "thwack", it means that the fruit is ripe.
Knocking on a watermelon is a pretty common technique... that is, if you know what you're doing. :p
But for those who don't, thankfully, someone has shared other ways you can choose the sweetest fruit.
Tip 1: Make sure it has a prominent yellow spot
The yellow spot indicates where the fruit sat on the ground and ripened.
If there is no spot, it means that it was prematurely harvested and is not ripe.
Tip 2: Look for brown spiderweb-like patterns on the watermelon
If there is a brown, coarse web pattern on the fruit, grab it.
This is caused by bees pollinating the flower and scarring the parts that form the fruit. So, the more pollination, the sweeter the fruit.
Tip 3: Black globs seeping out of the watermelon are a good sign
If there are black, hard globs coming out of the fruit, that is mostly likely sugar and is not insects or rotting.
And remember that if all else fails, you can always just buy it pre-cut. :p
Happy watermelon hunting!