Buying watermelon seems to be a bit of a black art, here are some tips I’ve picked up in the last couple of years:

1.  Select the right type of watermelon.

Until recently it was a little known secret that type 8424 watermelons were the sweetest and best tasting, now this is well known sellers will advertise when they have 8424 watermelons, you can expect to pay 1.2 to 1.3 kuai per jin although the price is a little lower at the moment because of the dreadful weather (they need to clear stocks before they rot apparently.) Of course, being Shanghai everyone wants in on the action and sellers who don’t have 8424 might mark theirs up as 8424 to increase the value of their stock. I asked one of my colleagues how you can tell which ones are the fake ones, “by the taste” he says, by which time it’s a little late of course..

2. Give it a tap

This seems to be an essential part of buying watermelon but I haven’t really got a clue how it works. Basically when you arrive at the store the owner will set off patting his watermelon one by one until finally he goes back to one he patted a second earlier and pronounces that this is the one. At this point it’s tradition to tap the watermelon yourself and give the guy a “listen mate, I wasn’t born yesterday” kind of look before pointing at the ones at the back, setting him off in another round of tapping, you can repeat this as much as you like. People tell me you’re looking for one that sounds kind of hollow but they ALL sound like that, nobody can’t tell me what a bad one would sound like.

2. Check the stalk

Have a look at the stalk of the watermelon, this tells you how fresh the watermelon is, the browner the stalk the longer it’s been sitting on the shelf. What you’re looking for is the combination of very fresh (green stalk) with ripe (hollow sound), if you’ve got a watermelon with what looks like a burnt twig coming out of the top which sounds ripe maybe it was picked young (I’m guessing here).

3. Check the yellow spot

Watermelon always have a light spot on the bottom where they’ve been lying on the ground, check that this has started to yellow and isn’t completely white, this is a good sign that the watermelon is ripe.

4. Check the weight

You’re looking for the one that feels heavy for its size, check a few of similar sizes to get an idea.

Oh, finally, expect to get ripped off on the weight a little. The last time I bought a watermelon I immediately took it to our lab to weigh on our highly accurate scales, the weight was around 10% less than the weight I’d paid for (despite the guy flashing his calibration certificate proudly), not sure if this is the norm.