To defrost one barrel of a two barrel FCB dispenser, a refrigeration system defrosts the one barrel, while neither defrosting nor chilling the other barrel, for either a selected time or until a frozen beverage is drawn from the other barrel, whichever occurs first. Once the selected time or beverage draw occurs, the refrigeration system chills the other barrel until beverage within it is properly frozen, while neither defrosting nor chilling the one barrel. Once beverage in the other barrel is properly frozen, the refrigeration system resumes defrosting the one barrel, whereupon the foregoing cycle is repeated until defrost of the one barrel is complete, at which point the refrigeration system chills the one barrel to refreeze product in it. The arrangement keeps beverage in the other barrel properly frozen during defrosting of the one barrel.