# What happens to potassium bitartrate (cream of tartar) at temperatures exceeding 1000°F?

What happens to potassium bitartrate (cream of tartar) at temperatures in excess of $\pu{1000\!^\circ F}$? For example, if it is placed on an oven bottom and then run through a self clean cycle.

If I remember correctly, tartrates of group 1 and group 2 metals are converted to the corresponding carbonates upon heating ($\pu{1000\!^\circ F = 538^\circ C}$).
In your case, potassium carbonate, $\ce{K2CO3}$, is formed.
Many of potassium bitartrate's Safety Data Sheets (available online) state that potassium bitartrate decomposes to carbon oxides at high temperatures (carbon monoxide and carbon dioxide), but don't state what that temperature is. Though the vast majority say something like "not determined," a few say it decomposes at temperatures >$200º\mathrm{C}\ (392º\mathrm{C})$. As long as you don't use too much and keep the area around your oven well ventilated, you could probably check this temperature for yourself.