Ƙarfin kunnawa (wanda kuma aka sani da kuzarin kunnawa) shine mafi ƙarancin adadin kuzarin da ake buƙata don halayen sinadarai ya faru. Ita ce makamashin da ake buƙata don karya igiyoyin ƙwayoyin masu amsawa da ba su damar sake tsarawa da samar da sabbin samfura. Ƙarfin kunnawa wani shamaki ne wanda dole ne a shawo kansa don amsawa ya ci gaba, kuma galibi ana bayyana shi a matsayin "matsala" wanda dole ne masu amsawa su share don isa ga yanayin samfurin. A wasu kalmomi, kuzarin kunnawa shine adadin kuzarin da ake buƙata don fara amsawar sinadarai.