Domestic laundry-washing appliance or dishwasher and optical sensor therefor

A domestic laundry-washing appliance including an optical measuring device for obtaining measured values which are representative of a spectral transmission signature of a washing liquid used during operation of the laundry-washing appliance for cleaning textiles, and a control device which is adapted to categorise a cleaning agent contained in the washing liquid in respect of its chemical properties on the basis of the spectral transmission signature obtained, and to control the operation of the laundry-washing appliance in dependence on the categorisation result. The categorisation result can indicate, for example, a distinction between a heavy-duty detergent containing bleach and another bleach-free detergent.