Though it is not known when Nestlé started working on his infant formula project, by 1867, Nestlé had produced a viable powdered milk product. His interest is known to have been spurred by several factors. Although Nestlé and his wife were childless, they were aware of the high death rate among infants. Nestlé would have been aware of Justus von Liebig's work in developing an infant formula. In addition, fresh milk was not always available in large towns, and women in higher society were starting to view breastfeeding as an unfashionable option.