It seems that Nielsen-Massey flavor extracts ought to be usable on Passover (perhaps with the requirement of purchasing them before the holiday.) Care to weigh in?
All of their flavor extracts use alcohol derived from sugar — sugar beets for their organic extracts, sugar cane for their other extracts. (I have email correspondence with them to confirm this if you want to see it. See also the 8th section of their “Dietary Needs & Certifications” FAQ here.)
All their products are certified kosher pareve by CRC, and all are certified gluten free.
I’m particularly interested in the vanilla extract and the almond extract. There don’t appear to be any problematic ingredients in either of them. (Neither chametz nor kitniyot.)
Vanilla Extract: Water, Alcohol (35%), Sugar, Vanilla Bean Extractives
Almond Extract: Alcohol (60%), Natural Oil of Bitter Almond, Water
Having looked through the ingredient lists for their entire catalog, it appears that all of their products might be usable on Passover. (Their vanilla beans are Passover-certified.) There are likely kitniyot concerns with their flavor powders (which contain maltodextrin) and their flavor pastes (which contain Gum Tragacanth, derived from a legume), but in both cases might these be kitniyot shenishtaneh?
Thank you.
Aaron Abadi 
michael aryeh 
Josh Wachtel
Good work. You’re right. The extracts should be good for all. Not kitniyot, because always batel berov (made irrelevant if less than 50%)