Methods and systems to manufacture a soap bar comprising post-brew coffee particles are disclosed. A soap bar may comprise multiple post-brew coffee ground particle sizes to take advantage of the benefits associated with each size. For example, the soap bar may comprise espresso grinds (0.20 mm), regular grinds (1.0 mm), and/or coarse grinds (1.5 mm). A saponified fat base, e.g., a milk soap base, a plant oil base, and/or an animal fat base may be obtained and heated to a consistency. Collected post-brew coffee grounds may then be added. The coffee grounds may be anywhere from 1% to 65% of the total weight of the final product, depending on the desired soap quality. The final soap product may comprise coffee ground positive and coffee ground negative layers or portion, or the coffee grounds may be evenly dispersed throughout the product.
