Xanthan gum is available in small quantities at Health Food stores, fairly expensive $8.50-9.00/6oz pkg. It will add viscosity but does nothing as a preservative. Mix with sugar or other powders, or add to oil before adding to water or vinegar solutions. Let stand 3-5 min stir, use blender for maximum thickness. Usage level start at .25% by weight and adjust from there depending on thickness desired. Fred Fatino AKA: The Creative Chef <A HREF="http://www.thecreativechef.com">http://www.thecreativechef.com</A>