> Medieval Europeans were fanatical about a strange fruit that could only be eaten rotten.

To be clear, you do not let the medlar "rot" before eating.

Rotting involves decay by microorganisms -- fungi, bacteria, yeasts.

What the medlar does is totally different. It has an enzyme within it that continues to break down the fruit, so it goes from rock hard to soft and edible.

Because this is a different chemical process from traditional ripening, someone gave this the name "bletting". But it's definitely not "rotting".

There's an evolutionary theory that by delaying when the fruit could be eaten, it could attract animals in the winter that would be more likely to eat it (since other fruits were no longer available) and potentially transport its seeds longer distances.

Quince and some persimmons are also commonly bletted before consumption... so it's not even unique to medlars.

Also, frost will trigger the process, so nowadays you don't need to wait so long for the fruit to decide to be edible if you put it in the freezer for a bit first.

You can say a fruit is ripening, rotting, or bletting.

Would you say a fruit is ripe, rotted… bletted? Blet?

Different from ripening? Ripening is a process in which enzymes break down cell walls, acids, and tannins, and break starches into sugars, isn't it? Bletting appears to be a second one.