Soaps are generally effective sudsing agents in warm and soft water only, although the volume and stability of the suds vary somewhat among products, depending on whether the soap is built or un-built and on the kind of fatty acids used in making the base soap.  Detergents are designed to have a wide range of sudsing characteristics.  Hand dishwashing detergents generally produce a high stable suds to mask the soiled dishwater and to serve as an indicator of residual cleaning potential. Automatic dishwasher detergents are low sudsing, as too many suds would cushion the washing action and interfere with cleaning.  Laundry detergents range all the way from high sudsing through a moderate or intermediate range to low, or controlled, sudsing, as judged by their appearance in the washing machine.  Low sudsing products are especially recommended for front-loading, tumbler-type washers and washer-dryer combinations, because too much suds in these washers cushions the clothes as they drop into the water after being lifted up in tumbler washing action, thus reducing the washing action and cleaning.