Jane Blair asks me to tell her about this confusing ingredient: Please tell me the difference between "tapioca flour" and "tapioca starch", and the difference between "potato flour" and "potato starch". Tapioca flour and tapioca starch are the same thing. Both are made from the cassava root that has been processed, dehydrated and finely ground to create a very fine powder. It is mainly used as a thickener in this form. Potato starch is however different than potato flour. Potato flour is the potato, cooked, dehydrated and finely ground. It is slightly yellow or off white in colour. Potato starch is just the starch of the potato that is processed from the potato. It is very fine, white, powdery and dissolves easily. Both can be used for thickening but the results will be different, it's the difference between using flour or cornstarch as a thickener. Think of the diffference between potato flour and potato starch as the same as corn flour and cornstarch. To complicate things a bit, if you come across something called "potato starch flour," it is the same as potato starch. Feel free to ask me any of your food questions, I pick a question once a week to post the answer in my blog. You will find lots more answers to cooking questions under the Foodies Ask category of my blog. Here are a few examples of what fellow readers want to know about: Molasses, Fancy or Blackstrap: What's the Difference How to Double a Cake Recipe Using Egg Substitues for Meringues The Ups and Downs of Baking Powder Gluten in Flour: Everything you Need to Know Can You Make Homemade Creme Fraiche