One of the hidden places that gluten lurks is in your vanilla extract. There are many brands of gluten-free extract you can purchase, but why not make your own? It is very easy and stores indefinitely.
1 fresh vanilla bean
3/4 cup vodka, see note below
Split the vanilla bean lengthwise down the center ofthe bean. Scrape out the seeds and place the seeds and the pod in a 1 cup sealable glass jar. Heat the vodka in a saucepan or in the microwave. Once hot, add it to the jar of vanilla seeds and pod. Seal the jar well and store at room temperature for one week. Shake the jar gently every day. If desired, you can strain the vanilla after the week is up. Store in a cool, dark place (a cabinet away from your stove or sunlight) indefinitely.
NOTE: You can check with the manufactureres, but at the time of print, the following vodkas are made with gluten-free ingredients.
Chopin Vodkas (potato)
Ciroc Vodka (grape)
Smirnoff Vodka (corn)
Rain (organic corn)
A list of vodkas from around the world and their ingredients can be found at wikipedia.