I’m sure you’ve already done your internet search for this at this point. However, I found this very useful as I was intrigued by the question. http://www.practicalpantry.com/staples/page20.html.
Here’s the text of it:
Extracts are concentrated flavorings used in cooking and baking. When stocking a pantry for baking, vanilla extract is practically a necessity. Other extracts, such as almond, orange and lemon, also are good to have in the pantry.
Points to Remember
Do not add vanilla extract to hot liquids as the alcohol evaporates, along with some of the vanilla flavor.
Some people enjoy making their own vanilla extract with vanilla beans and vodka. The Food Network and Baking 911 have easy recipes and instructions on their websites.
The flavor of almond extract is very intense, so use it carefully.
Storing
One opened, extracts should last about one year. Keep tightly closed.
Substitutions
In a pinch, you can substitute maple syrup for vanilla extract, teaspoon for teaspoon. For 1 tablespoon vanilla extract, you also can substitute 1/2 vanilla bean, scraped, combined with the liquid used in the recipe.
For a 1/2 teaspoon lemon extract, you can substitute 1 teaspoon grated lemon zest.
For 1 teaspoon of an flavor extract, substitute 1/4 teaspoon flavor oil. However, if a recipe calls for flavor oils, do not substitute flavor extracts. Oil based flavorings, often used in hard candy recipes, do not add liquid to the syrup.
Pure extracts and artificial extracts can be used interchangeably.
I wish you fabulous cookies!!!!