A method of preparing a single serving of a nutritional composition comprising introducing water into a disposable capsule (30) containing a unit dose of the composition in concentrated form so as to reconstitute the concentrated composition and operate opening means contained within the capsule to permit draining of the resulting liquid directly from the capsule (30) into a receiving vessel. The method allows individual servings of nutritional compositions such as infant formulas to be prepared with substantially reduced or even eliminated risk of cross contamination from previously prepared servings.