The caffeine content in bubble tea can vary significantly depending on two main factors:

Tea Base: The tea itself is the primary source of caffeine in bubble tea. Bubble tea can be made using different tea bases, such as black tea, green tea, or oolong tea. Each type of tea has a different caffeine content. For instance, black tea generally contains more caffeine than green tea. Therefore, bubble teas made with black tea tend to have a higher caffeine content than those made with green or herbal teas.

Ingredients: Besides the tea base, other ingredients can influence the bubble tea caffeine content. Some recipes call for added coffee or espresso, increasing caffeine levels. Additionally, flavored syrups and powders may contain trace amounts of caffeine.