Short answer: the classic bubbles are tapioca pearls from cassava. Below: a comparison table of every topping, calories, textures and how to pick.
The chewy black balls in bubble tea are tapioca pearls, made from cassava root starch, water and brown sugar. Confusingly, the drink is not named after them: "bubble" originally referred to the foam produced when the tea is shaken with ice.
Two kinds of bubble
- The foam. Taiwanese shops in the 1980s shook tea, milk and sugar in a cocktail shaker, producing a layer of bubbles on top. That is where "bubble tea" comes from.
- The pearls. Tapioca balls sitting at the bottom of the cup, drunk through a wide straw. In Mandarin they are zhenzhu, pearls, which is why the drink is also called pearl milk tea or boba.
What tapioca pearls are made of
| Ingredient | Purpose |
|---|---|
| Tapioca starch (cassava root) | The body of the pearl and its chew |
| Boiling water | Gelatinises the starch so it can be kneaded |
| Brown sugar or caramel | Colour and flavour — this is why they are dark |
| Sweet potato starch (optional) | Extra elasticity in some brands |
That is the whole list. No gluten, no dairy, no gelatin, no caffeine. Cassava is a root vegetable grown across South America, Africa and Southeast Asia; the starch is washed out of it, dried and rolled into spheres.
Every topping you might find in the cup
| Topping | Made from | Texture |
|---|---|---|
| Classic black pearls | Tapioca starch and brown sugar | Dense, sticky chew |
| Crystal boba | Agar or konjac | Springy, translucent |
| Popping boba | Juice in an alginate skin | Bursts |
| Lychee or grass jelly | Agar or grass jelly herb | Soft cubes |
| Aloe vera | Aloe flesh in syrup | Crisp, slippery |
| Red bean | Sweetened adzuki beans | Soft and mealy |
| Pudding | Egg custard | Silky |
| Cheese foam | Cream cheese and milk | Salty foam cap |
Are the bubbles safe and are they vegan?
Tapioca pearls are vegan, gluten free and safe to eat. They are high in carbohydrate and low in nutrients — around 180–220 kcal per 100g cooked — so they add calories without much else. Cassava must be processed before eating, which commercial starch always is. Children should drink boba with a straw wide enough that pearls are not gulped whole.
Why the pearls are chewy
The chew is called QQ in Taiwan, a texture word with no direct English equivalent. It comes from gelatinised starch: boiling water breaks the starch granules open, and as the dough cools the chains re-bond into an elastic network. Cook too briefly and the centre stays chalky; too long and the pearl loses structure and turns to mush.
People also ask
- What is popping boba made of?
- Fruit juice sealed in a thin seaweed-derived alginate skin, set with calcium — no tapioca and no gelatin. Read the full answer
- What is crystal boba?
- Translucent agar jelly pearls with a springy bite and roughly a third of the calories of tapioca. Read the full answer
- Crystal boba or tapioca pearls — which should you use?
- Crystal boba is lighter, clearer and holds texture for hours; tapioca gives the classic dense chew of a milk tea. Read the full answer
- How is popping boba different from tapioca?
- Popping boba bursts with juice and needs no cooking; tapioca is boiled starch with a chewy bite and works hot. Read the full answer
Building a boba business?
Our hands-on bubble tea training in London covers drink prep, machines, costing and menu build, taught by the team running our Fulham bar every day.
