Instant tea powder may be produced by evaporating already prepared tea until a dry powder remains. Another method evaporates tea directly from a fermented leaf at a low temperature. Trade Tea is sold at auctions, privately traded, or sold in local tea markets. The first London public tea auctions were held in 1834. Today's London auctions deal in teas from about 25 countries.
Many centers deal with teas produced in their own countries or regions.
Before an auction begins, tea chests are lined up in long rows in a warehouse. A hole is bored in each chest, and a sample of the tea it contains is withdrawn and sent to the leading buyers. The buyers bid on, or make offers to buy, the tea. The buyer making the highest bid for a tea gets it. The buyer then ships it to fill an order or sends samples to importers throughout the world, and they may order some of it.