Change your recipe at your stand when you see that customers aren't enjoying their lemonade, when you think you'll run out of stock before the end of the day with your current recipe, or whenever the time seems right.
To change recipe, click your stand, and then click the Recipe button. Use the plus (+) and minus (-) signs to make the changes you want, and then click Change Recipe.
If you have cups of lemonade left in your pitcher, you will flush those cups by changing your recipe and filling a new pitcher.