The "hot process" refers to a method of making soap where the ingredients are heated during production. This technique involves cooking the soap mixture, which accelerates the saponification process, allowing the soap to be ready for use more quickly than other methods. In this process, oils and fats are combined with a lye solution and heated until they reach a specific temperature. This results in a more robust soap that can be customized with various additives, such as essential oils or colorants, to enhance its properties and appearance.