Bitterness is one of the most intriguing of human taste sensations, but why do we detect bitterness at all, if - as generally is the case, it is an unpleasant sensation?
Most of the bitterness we encounter on a day to day basis is provided by plant borne alkaloids, and many of these alkaloids are indeed poisonous. It makes sense then, to assume that humans (and many other "higher" animals) have the ability to sense bitterness as a warning. However, this is not where bitterness as a warning signal originated. Coelenterates, a primitive class of sea dwellers including jellyfish, anemones and coral have been found to posses a strong aversion to bitterness that some hypothesize to be a warning sign for heavy metal contamination. Bitterness as a sensation has been around a lot longer than humans.
Not all bitterness need be dangerous - or indeed unpleasant. Two bitter compounds that humans actively seek out are caffeine and quinine, and the bitter melon possesses quinine in abundance.
Bitter melon Momordica charantia, which is also variously known as bitter gourd, bitter cucumber, the balsam pear and even the leprosy grape, is a smaller relative of the wild grape vine and is native to Southeast Asia and Southern China.
As with many Asian foods, the bitter melon was not originally consumed as a foodstuff, but as a medicine. The plant's curative properties are many; from a blood purifier to a diabetes treatment and a stimulant for nursing mothers milk production. Late research has found the bitter melon to be an important dietary supplement for individuals suffering immune system damage, and as such is being investigated as a possible treatment for those living with HIV. The leaves were even used to treat elephants with eye complaints!
So if you are not in need of any medical treatment and are not currently in possession of a sore-eyed elephant, why would you want to eat a bitter melon?
Well I won't lie to you, their title is not a misnomer, they are bitter - gaspingly so. I will never forget my first encounter with bitter melons; it came as a real shock. It was in a Thai soup of roast duck and bitter melon. The soup was delicious, full of deep and long duck flavours enhanced by the mysterious star anise. Then I bit into the melon. Once the initial horror of the extreme bitterness had subsided I found that I was not only enjoying it - but actually craving more, in much the same manner the heat of chilli commands continued palate abuse. Apart from the obvious bitterness it had a mild cucumber like flavour and a pleasing crunchy texture.
The culinary uses of the melon are many. In China they are often stuffed with a highly seasoned pork mixture and fried. Indian cooks often make pickles out of them, while in Sri Lanka there is a famous sambal of bitter melon, coconut milk, chillies and shallots. The intrepid Burmese actually eat it raw in a salad of onion and garlic. The one constant is the accompanying flavours will be bold, so as to match the pungent flavour of the melon.
The bitter melon also possesses a strikingly original appearance. Somewhat resembling a cucumber in shape, they range in length from 10 - 30 cm. The colour starts out as bright green when immature, moving to pale green when ripe, finally changing to yellow and orange when overripe. The skin of the melon has a highly knobbled texture that can only be described as warty.
When purchasing bitter melons, look for firm, pale green specimens and avoid any that are yellowing and split open - as they will be tough and aggressively bitter.
The bitterness can be toned down a little with careful preparation. Split the melon in half lengthways, scoop out the seeds and discard. Slice the melon into 1 cm wedges (unless you are stuffing the melon - in which case leave them in halves), place in a colander and sprinkle liberally with salt. This is a process known as disgorging and will not only draw out moisture, but some of the bitterness as well. Leave to drain for around 1 hour. Rinse the melons of excess salt and plunge into boiling water for 2 minutes. Immediately drain and run under cold water to stop them cooking any further. You are now ready to proceed with your recipe - the bitterness will be reduced, but still strong.
If you are looking for bitter melons in an ethnic market, here are some regional names to help with your search.