When substituting lemon concentrate for real lemon juice in a recipe, use two tablespoons of bottled lemon juice to replace the juice of one lemon. Bottled lemon juice is made from a lemon juice concentrate and lemon oil and is a stable product that maintains its freshness for up to six months in the refrigerator. Substitute lemon juice concentrate for equal proportions in any recipe calling for lemon juice.
Before using lemon juice concentrate, it is important to shake it well to prevent settling and separation of the concentrate. While fresh lemon is often called for in recipes, others such as canning recipes specify bottled lemon juice due to its required acidity and its affect on the pH of certain foods. Unopened bottled lemon juice concentrate should be stored in a cool and dark location.
If bottled lemon juice concentrate is not available, other substitutes such as lime juice or white wine may be used to match the acidity of lemon juice. Both of these can be substituted at a one-to-one ratio. A mild vinegar can also be substituted for lemon juice at a rate of a 1/2 teaspoon per each teaspoon of lemon juice called for in the recipe.