Question

Butter became sour if kept in summer for long time.Why?

Answer 1

when butter is kept open in summer than it reacts at room temperature with air and produces salt as waste product of the reaction

hope it helps you

Answer 2

heya folk

butter becomes sour if kept in summer for long time due to rancidity I.e spoilage of food

Butter and oils will go rancid if exposed to light, heat or air. For this reason oil should be kept in a cool dark place( when in bottle ).

as during summer there will be Hugh amount of heat , rancidity takes place and they become sour