- It is sometimes customary to substitute for lemon juice a yellow solution of citric acid. This of course is simply an adulteration, and a very undesirable one at that. Anyone who has ever compared the flavor of a real lemonade, either straight or at a soda fountain with carbonated water, with an artificial preparation of a yellow solution of citric acid, will understand exactly the force of this admonition. The same is true of orange, where a little orange peel or the flavor thereof and citric acid colored yellow is employed. All of these practices are properly catalogued under the head of adulterations.