A method of fighting a fire includes aerating a firefighting foam composition to form an aerated firefighting foam; administering the aerated firefighting foam to a fire or applying the aerated firefighting foam to a surface of a volatile flammable liquid; wherein: the firefighting foam composition includes a sugar component; a surfactant component comprising an anionic surfactant, a zwitterionic surfactant, or a mixture of any two or more thereof; a polysaccharide thickener comprising succinoglycan; and at least about 30 wt. % water.