Our area, North Sumatra that is, is famous of its passion fruit juice. The area’s souvenir shops don’t actually sell cheap and flimsy key chains, fridge magnets or t-shirts. The shops are packed with bottled passion fruit syrup, swiss roll cakes, bika ambon (a type of sand-cooked coconut cake, which I might never feature in this blog), peanut brittles, fried cassava chips and many more. Passion fruit syrup sold in the shops has gone through simple cooking process, slowly heating the juice and sugar, sometimes preservatives are added. The cheaper version would be purely passion fruit essence and sugar with water. The local name for this is Jus Markisa. A pretty name for such a sour fruit. Markisa syrup, sold commercially, would have a lot more sugar in it and needs to be cooked and naturally slightly thicker. To serve the syrup, dilute 1/4 of syrup with water.
Households in our area usually would prepare passion fruit drink in form of fruit juice, without any heating process and no sugar. It is believed the cooking will prolong the shelf life, but also killing the natural flavor of passion fruit, which explains the need of artificial flavoring in commercially sold syrup. Homemade version of passion fruit drinks would be simple juice, served with a lot of ice cubes to dilute and sugar syrup to taste.
This is how we do it at home. Our house makes this often, but always for out-of-town guests so they can bring them back when they leave. The homemade juice has to be refrigerated at all times and consumed within a week.