"Horchata" is a vegetable milk obtained from tiger nuts. The solid waste from horchata production was analyzed for physicochemical and microbial properties, aiming to determine its potential use as a fiber source for the food industry. The solid waste contains a high proportion of total dietary fiber (59.71 g/100 g), composed mainly of insoluble dietary fiber (99.8%). It has a high water-holding capacity (8.01 g/g) and oil-holding capacity (6.92 g/g) and a low water absorption (1.79 g/g) and water adsorption (0.23 g/g) capacities, in comparison with other dietary fiber sources. The emulsifying ability was 70.33 mL/100 mL, and the wastes showed high emulsion stability (100 mL/100 mL). The physicochemical properties indicate that tiger nut byproducts are rich in fiber and may be considered a potential ingredient in a healthy diet. However, the microbial quality was poor, meaning that it must be pasteurized prior to its addition to any food product.