Bubble tea can feature different types of "bubbles," but one popular variety, known as popping boba, is made using a fascinating technique called spherification. This process transforms flavoured liquids into small, bursting spheres.
Making Popping Boba: The Spherification Process
The creation of these specific bubble tea bubbles relies on a simple yet effective chemical reaction. It involves carefully combining two solutions to create a thin, gel-like skin around a liquid centre. This process allows for a wide variety of fruit juice flavours to be enclosed within the edible sphere.
The Key Ingredients and Steps
According to the process described, the bubble-making involves two primary components:
- Flavoured Liquid with Sodium Alginate: The process begins with flavoured juices. Importantly, these juices must contain no calcium. A small amount of sodium alginate is then mixed into the calcium-free flavoured juice.
- Calcium Chloride Solution: A separate container is filled with a cold solution of calcium chloride.
The bubbles are formed by carefully adding the first mixture into the second:
- Mixing the Flavour: The chosen flavoured juice (free of calcium) is combined with a small amount of sodium alginate.
- Dropping into Calcium: The mixture of alginate and flavoured liquid is then dropped, usually using a dropper or syringe, into the container filled with the cold calcium chloride solution.
How the Bubbles Form
As each drop of the alginate liquid enters the calcium solution, a reaction occurs immediately. The calcium ions from the calcium chloride interact with the sodium alginate molecules. This interaction causes the alginate molecules on the surface of the drop to link together, forming a thin, flexible skin around the liquid centre. The cold temperature of the calcium chloride solution helps the bubble maintain its shape as the skin forms.
This method results in the signature popping texture: the thin skin contains the liquid flavour until bitten, at which point it bursts in your mouth.
While traditional bubble tea often uses chewy tapioca pearls, the method described above is specifically how the popular bursting, or "popping," bubbles are created for a different kind of bubble tea experience.
