You may be tempted to use store-bought cranberry juice, which I can understand due to the small amount of cranberries needed and the added step in the recipe. Just note that store-bought juices sometimes contain more than just cranberry juice ("cranberry juice cocktail"). Also, store-bought juice will be thinner than what I used, since it contains no pulp at all. This means that if you use store-bought juice, you will need less of it to reach a glaze consistency, and your flavor and color will likely not be as strong as mine.