All of the above! Most people think only of wheat when they think gluten. However, there is a whole family of grains and derivative products made with wheat that also contain gluten.
Wheat does contain gluten, so all things gluten free are wheat free. However, gluten can be found in several grains, including rye, barley and spelt. This means a product containing one of those ingredients could be wheat free but not gluten free. A great example of this is Kellog's Rice Krispies. The cereal does not contain any wheat, but does contain malt flavor which is made from barley. This product is wheat free, but not gluten free.
Despite it's name, buckwheat is not related to wheat at all and is safe for a gluten free diet.
While oats themselves do not contain gluten, many brands are contaminated with wheat or barley during the manufacturing process making them unsafe to eat. The good news is there are several varieties of gluten free oats available that ensure cross-contamination has not occurred. Just make sure your label says "Gluten Free."
Quinoa! This super-grain is perfectly safe for a gluten free diet. Unfortunately, wheat starch is a common ingredient in soy sauce, HVP and self-basting turkeys.
The Butterfinger candy bar is gluten free! Believe it or not, Twizzlers contain wheat starch and both the Milky Way and Malted Milk Balls contain barley malt.
Not necessarily! If the chips are fried in the same fryer that is used for flour tortillas, etc they are no longer safe to eat. Cross-contamination is a common reason naturally gluten free foods are no longer gluten free. Be mindful of shared fryers, toasters, utensils, etc.
No, never. I know, you are going to tell me not everyone is a Celiac and that some people are just making a personal choice. While that may be true, it is not your job to quiz your customers on their personal health. Just make sure things that are labeled gluten free are truly gluten free and all your diners can leave happy and healthy!
Many are not so be sure to check the ingredients. Lea and Perrins is gluten free.