A batch reactor is a vessel used to mix chemicals under tightly controlled conditions. It is distinguished from a continuous reactor by its cyclic use, mixing one batch at a time, as opposed to the constant reaction carried out in a continuous reactor.
A typical batch reactor consists of a large, sturdy canister with its own heating and cooling mechanisms. Inside the vessel is a rotating agitator that facilitates mixing. At the top of the reactor are input ports that permit the addition of chemicals to be mixed. Batch reactors are frequently used in the creation of dyes and some food products, such as margarine.