Fiber-containing products are described that include a cured binder formed from a binder composition that may include a sugar alcohol having three or more carbon atoms, and a polymeric polycarboxylic acid. The binder composition may be characterized by a mole ratio of hydroxyl groups to carboxylic acid groups greater than or about 1.1:1. The fiber-containing product may also be characterized by a thermal stability that is greater than a comparative fiber-containing product made with a comparative cured binder that includes the polymeric polycarboxylic acid but lacks the sugar alcohol. The fiber-containing products may include thermal insulation products such as building insulation, pipe insulation, duct insulation, and appliance insulation.