At home Rochelle's salt synthesis

I tried to make Rochelle's salt. It didn't work!


* 7 oz cream of tartar
* 1 cup distilled water
* heat to 180 F and keep there
* add 1/2 tsp sodium carbonate at a time until there is no fizzing
* filter and let cool


The solution ended with a strong yellow/brown tint. It took at least an hour of adding sodium carbonate. While cooling it rapidly formed a crystallized honey look and that was it. I reheated and added more distilled water to lighten it up a bit thinking it needed to evaporate slower. This time when it cooled nothing happened.


The sodium carbonate was 100%, and the cream of tartar was McCormick. It's possible that came with some impurities hence the brown/yellow grossness. 


Is there as way to save this batch? Should I just try again? Is there a better recipe? 


My first instinct is that it didn't work because you don't science with Imperial units.




Tried again with 365 brand (whole foods) Cream of Tartar. Worked much better.


* 39g Cream of Tartar
* 50ml distilled water
* Sodium Carbonate added slowly until stirring produces clear liquid


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