In the Dunlop process, natural rubber tree sap is poured into a mould before being cooked in a process called vulcanization. Before the latex is rendered into its solid state, any natural sediments within the mixture settle to the bottom, resulting in an inconsistent latex core that is softer on the top and firmer on the bottom. By comparison, the Talalay foaming process takes place in a vacuum chamber, and yields a far more consistent product due to the fact that the latex is flash frozen before vulcanization. This step evenly suspending any particulates, resulting in consistent firmness throughout the core. Besides their production processes, Dunlop and Talalay also differ in their buoyancy – Dunlop tends to be heavy and dense while Talalay is soft, bouncy and resilient. Lastly, Talalay is available in five firmnesses while Dunlop is only available in three.