The present invention relates to a method for manufacturing a brine with improved features for use in food as a condiment and for the preservation and treatment of fish and shellfish, improving the organoleptic and nutritional properties of the foods treated and/or cooked with it. The brine with improved features obtained according to the method of the present invention can furthermore be used as raw material for manufacturing intensely hydrating and mineralizing isotonic beverages for human consumption, as well as any food product requiring water in the manufacturing process, improving the nutritional properties thereof. It can also be used as raw material for manufacturing products with a high nutritional value in agriculture and stock raising, in the food industry, in other industries and in health treatments.