I have cheap culinary vanillin and I can't guarantee it's pure, otherwise it wouldn't have been that cheap. It doesn't seem to have obvious fillers like starch and acts predictably in baking but still. Would it be safe to use it or should I search for something more refined?
Search for something more refined, such as: TFA Vanillin 10
I bought Ethyl Vanillin crystals to dissolve in PG to make my own vanillin flavoring.
What’s the Difference: Vanilla vs Vanillin vs Ethyl Vanillin
Interesting link below the image of cookies at the page above. I wonder if they asked /u/clinodev before including it?
Vanillin is cheap. It's a bulk commodity food grade good that's added to an absurd number of products (wiki says 12,000 tons in 2001, and you probably already know you need to dilute it down quite a bit to get to the "vanilla extract" level.)
Apparently it's being used in some tumor trials, so there is "Pharmaceutical Grade" vanillin on the market, but looking at the prices, I'm pretty sure the vanillin in dozens of common food flavorings you already have in your DIY box is exactly the same as the white crystalline powder you bought from a culinary supplier.
I'd say the same for ethyl vanillin. To be honest, the other minor synthetic vanillas I played with were all too strong for me to work with. I'd leave those to the professionals.