What does it mean when chocolate seizes?
Chocolate that is being used to make a sauce or candy truffles is usually melted. When in this molten state, it must not come into contact with any liquid whatsoever. While you may melt chocolate in a larger amount of liquid, it cannot be combined with any liquids once it has itself been converted to a liquid chocolate state.
Melted chocolate seizes or hardens and clumps into a horrible solid mass when it comes into contact with any liquid, even a drop of water. If this happens, try adding a tablespoon of vegetable oil to the mixture immediately, set the hardened chocolate in a pot over simmering water, and try to re-melt once again. This solution can sometimes save the day.