Bael tree is indigenous to Indochina and South East Asia. The fruits have a firm outer surface that turns yellow when ripe. The inside of the fruit has a hard central core and triangular segments, filled with a pale orange, sweet pulp. Seeds enclosed in a mucoid sac are lodged in the pulp.
Ask for ma-tuum or matoom which is the local name of the fruit. The Bael fruit drink is an effective thirst quencher. It tastes rather bland, with sugar added to taste. It created no remarkable impression when I first tasted it.
I would not suggest having the drink together with food because by nature of its very bland taste, drinking it after a mouthful of curry or any other spicy morsel can actually overpower its taste so much that the bael fruit juice can be rendered tasteless.
The very helpful waiter brought me a little sachet of brown Matoom powder from which the drink was prepared. Just the addition of water and ice! I learnt that it was available at herbal and medicinal shops, since bael fruit, considered as having health giving properties, is used variously for digestive, laxative and tonic properties. Quite useful if you are a backpacker!