We were melting chocolate a while back for some mousse and ran into one of our of our kitchen nightmares. One minute, the melted chocolate was so smooth and velvety that it was hard to resist drinking it straight from the bowl. The next minute, it had clumped up into a thick dull paste. Ever had this happen to you?
Here's the simple reason why melted chocolate seizes and how to make sure it doesn't happen to you.
Water Is the Enemy of Melted Chocolate
The process of refining cocoa beans into chocolate gets rid of all the moisture, and so the final product is actually incredibly dry. Technically, even melted chocolate can be considered a 'dry' ingredient despite its liquid state.
For this reason, adding water to melted chocolate has the same effect as adding water to flour—it turns into a paste. Food science Harold McGee explains that "the small amount of water acts as a kind of glue, wetting the many millions of sugar and cocoa particles just enough to make patches of syrup that stick the particles together..."
If a bit of water accidentally gets splashed in your bowl, you may still be able to resuscitate the chocolate by adding cream and using it as a ganache or sauce. The cream will incorporate more smoothly with the cocoa solids and sugar particles in the chocolate.
Chocolate can also seize if it gets too hot and scorches. This it's best to heat it gently over a water bath or in 20-second increments in the microwave, being sure to stir occasionally so the bottom doesn't burn.