I bought this brand of Stevia based on Hayley Pomroy's recommendations (author of "Fast Metabolism Diet").  She is a nutritionist and researches the source of products she recommends with her diet which is to repair the metabolism.  This Stevia has Xylitol as a flowing agent (as many do) but it is hard wood (birch) based.  Not corn based.  It is very sweet and tastes natural to me.  No after taste.