<<Disclaimer: Verify this information before applying it to your situation.>> Howdy - the following summary is in response to my question of: what the shelf life of Xanthan Gum is? I was wondering because I have been using the same jar of it for several (4) years! However I am using it more now as I have become more comfortable with gf baking at high altitude. Anyway - several people were interested in the answer. I had five responses with information. Thank you everyone VERY MUCH. I would say that the consensus is that it lasts for at least a year or more. Thats good to know. 1. Check the bottom of the bottle. I've had mine for a month or so (who knows how long it was on the shelf) & the expir. date on the bottom says 05/2000 so that's a long time. Hopefully you would use it up long before the year 2000. It's from NOW Foods, Glendale Hts, IL 60139. Happy baking!! 2. Xanthan Gum will keep indefinitely as long as it is kept dry. 3. If xanthan gum is stored in a cool, dry place away from heat it should easily last 1 year. Jay - Miss Roben's, Inc 4. I have some which I used this week that said exp. 4/98. I used it in a cake which turned out delicious as ever. 5. I don't know, but I read in the archives to keep it in the refrigerator, and I do, in a Tupperware container. It's been 6 months so far and it seems fine. -Laurie (SW Colorado)