Im in Thailand, Bangkok, at the moment for a week. My main purpose for coming here was to eat Durian, the King of Fruits. It is one of the best fruits in my opinion...but only when you eat the right kind of Durian, meaning the one which is perfectly ripe. Not too firm, not too mushy.
My first experience with Durian was rather disappointing. I bough it from the shop in Australia, the frozen one. It had no smell what most people would prefer (since it is famous for its odd smell), but i think the smell is an important part of telling if the fruit is ready to eat or not.
However, some people like to eat Durian when it is unripe and firm. But i think its well worth to try the real ripe taste of this amazing fruit.
The smell of a ripe Durian should be a little fragrant, but not too overpowering. Also, if you cant smell much of anything or its smells as if it is raw, it probably is. The ripe Durian smell itself is described as "big-shit, turpentine and onions, garnished with the smell of gym" :) I dont find the smell disgusting anymore, i guess it just takes time to get used to. You can also describe the smell as "smoked oak and bitter sweet honey butter". The smell is very good as a "Durian finder" for me. If im searching for a Durian sellers in Bangkok, then i can smell Durian before i see the seller. So i can follow the smell and find my Durian :)
Because of the strong and disgusting (not for me at least) smell, Durian is even banned of most public places like hotels, airports, public transportations, cinemas etc.
In Bangkok, Durian is found mostly all year round. But the high peak season is from April to August. You can find cut out Durian pieces in shopping centres, but my favourite place to buy Durian is at the markets on the streets. Mostly because i get a bargain price. In supermarkets the price can be even 3 times more expencive.
I like sellers who sell Durians on two-wheeled carts. They move around constantly, but you can find them on the main shopping streets usually, but i spot them on pretty random places as well.
They also sell packaged Durian pieces, what are left from the whole Durian when its cut open. But i strongly advise you to buy a whole Durian. Since i have had bad experiences when the pre-packaged pieces are gone bad by staying out maybe all day, and it is pretty hot here. So buy a whole big one. If you cant eat whole one, then share it, refrigerate it, or simply wait when you are very hungry and then you can eat the whole thing. The whole durian is about 800-1000 calories. So perfect for an entire meal for fruit loving people.
Before you buy your fruit from the seller ask him/her if it is the ripe and soft one, since some sellers think that most tourists dont like the "soft and smelly and prefer firm and tasteless" one. Yes, thats what they told me, when they accidentally sold me the firm and unripe on. It was totally tasteless. Make sure it is soft inside and ask the ripe on, usually sellers know which one is the best. But dont let yourself be fooled by buying pre-packaged soft Durian. Softness is not the only indicator it is good. I thought it is, and got the worst overripe "big-shit, turpentine and onions, garnished with the smell of gym" fruit. I think when durian is overripe, it truly is disgusting. Im sure when people first taste Durian and think its worth vomiting, its usually the bad one (not ripe or overripe) and they assume all Durians are like this. Durians have to be perfectly ripe, to taste incredibly good.
But how you know if Durian is ripe, just by looking at it?
First you can look the stem. If its too dry, then it has been sitting out too long and is an old one. Dont buy it. People also smell the bottom of the stem. If the smell is strong, its ready to eat. Stem should be thick and solid.

Look for the Durian what seems light for its size and is beginning to split longitudinally. You can also make a hearing test. If you shake the fruit next to your ear and hear vigorous hallow movements of seeds, it means it is not ripe. If you hear absolutely nothing it can mean its overripe. You should hear a slight movement inside for it to be just perfectly ripe.
Make sure there are no rotting spots or holes. Holes mean that fruit has been attached by parasites or squirrels. But then again - if a squirrel likes it, it might be a very good tasting one. Also, if insects like it, it can be because no pesticides have been used.
Here you can see a video of
how to cut open a Durian.
I noticed that, when i eat Durian on the streets, then locals stare at me or make an approving comment as if i am the only crazy tourist who has ever appreciated the taste of Durian :P