Ship's biscuit used a simple recipe of flour, water, and salt. Baking it four times for sea service, compared with twice for land use, drove out more moisture. Preparing it six months before sailing also provided time to check whether it would spoil, although this meant the first day's ration was already six months old. Mixed into broths with meat and vegetables, the biscuit thickened the liquid and made the meal more filling and palatable. It also supplied carbohydrates.
Chapter · 6:23-7:55
Ship's biscuit for voyage endurance
Repeated baking removed moisture from ship's biscuit so it could survive long storage and later thicken broths made from meat and vegetables.