Drinkers of bubble tea are bracing for the worst. Boba balls, the tapioca-based spheres that collect at the bottom of a cup of this wildly popular Taiwanese beverage, are reportedly in short supply. Bubble tea is a combination of milk and tea, shaken or stirred to create the namesake bubbles. The boba balls sink to the bottom of the cup, waiting to be sucked up through an extra-wide straw and chewed with the sips of tea. Boba—as the kids call this wildly popular beverage—has spread throughout East and Southeast Asia and is available wherever such food is sold. Taiwan exports boba balls worldwide—in several colors, and sometimes even with little juice pockets inside. The diversity of boba tea recipes is like a drinkable distillation of the myriad Asian food scene: Vietnamese coffee boba, Japanese matcha with cheese foam, potted plant boba, black tea with strawberry gummy bears. The popularity and …