What are those chewy balls in your bubble tea? Are they sago or tapioca? Are sago and tapioca the same?
Strictly speaking, sago is made with the starch from the pith of an array of tropical palm trees. Tapioca pearls, as the name so clearly tells us, is made with tapioca or the starch from cassava, a root crop. While the use of the starch is not always interchangeable, when the starch is cooked in pearl form, it really is overkill to be obsessed with the source of the starch.
The chewy balls that the world has so fallen in love with since the advent of bubble tea are tapioca balls. And although some claim that sago balls are larger than tapioca pearls, it just isn't true that one can easily tell the difference between sago and tapioca pearls by their size. Both are sold in different sizes, colors, and flavors. To make sure whether you're getting sago or tapioca pearls, check the ingredients list in the packaging. In most parts of Southeast Asia, tapioca pearls can be bought already cooked and ready for use. For the rest of the world, tapioca pearls are sold in dried form and require boiling before use.
Is the color of the tapioca pearl based on its flavor? Not always. In most cases, the coloring is artificial and only meant for visual excitement. If artificial food color is something that scares you, go for the white tapioca pearls. White is their natural color because they are made from starch.
They are neutral-tasting as well because starch, although it has a distinct sensation in the mouth, does not really have any memorable flavor.
In its dried form, a tapioca pearl is white and opaque. After cooking, the sphere swells to almost twice its original size and becomes translucent.
What is the proper way to cook tapioca pearls?
Some cooks insist that tapioca pearls must be soaked in cold water before boiling. I find this to be completely counter-productive because the starch starts to dissolve in cold water immediately upon contact and the pearls loose their shape even before they reach the stove. It's the same principle when using tapioca starch in powder form. Disperse a teaspoonful of starch in room-temperature water and the starch mixes into the water. But drop a teaspoonful of tapioca starch in hot water and it will form into a lump.
So, unless you're making a pudding with your tapioca pearls, skip the soaking part. I never ever soak tapioca pearls. I add them to the water only AFTER the water has reached boiling point. I also make sure that the tapioca pearls boil in plenty of water. Four cups of water for every cup of dried tapioca pearls is a good starting point. More won't hurt but less water is not recommended. And I stir often during cooking. The tapioca pearls never cook all at the same time. Some will still have an opaque center when most are fully translucent. I take the pan off the heat at that point and strain the tapioca pearls.
Finally, I rinse the cooked tapioca pearls in cold water.