Cucumbers can be bitter, and that's because of cucurbitacin: A compound found in a number of other plants, like squash and pumpkins. In cucumbers, cucurbitacin concentrations are high at the ends of the cucumber, so chopping off those ends will curb a lot of the bitterness. You can take this one step further by peeling the cucumber first. Photo by theilr
As Epicurious explains, cucurbitacin is found in the peel, too. And many people will cut then peel the cucumber to get rid of the bitter flavour. However, there's a better way:
Always cut the ends off of cucumbers before you peel them. Fail to do this, and each time you scrape the peeler down the cucumber's length you'll spread bitter cucurbitacins to the rest of the vegetable.
We've told you before that rubbing the cucumber might work, but this method ensures you just get rid of the cucurbitacin concentrations to begin with. For more detail, head to the link below.