I was making a very reduced duck stock as the first step to making duck terrine. Yesterday I made the stock and started reducing it but ran out of time so I refrigerated overnight. This morning I skimmed the very small amount of fat off the very gelatinous top and started reheating it to keep reducing it. It fully melted, I stirred it through, then a couple minutes later I walked by and took a look -- did not seem to be simmering or boiling -- as I got to the other side of the kitchen I heard a sound and turned to see the stock erupt like a geyser. I have never seen anything like it. Thank goodness I wasn't standing over it -- I'd be in the hospital right now, for sure. Does anyone know why that happened? The more I think about it, the scarier and more mysterious it seems.
Only a small amount of stock remained in the pan after it happened -- the rest was on the walls, floor, under the burners of the stove, etc (and just SOOOO much fun to clean up).