A winemaker's term for pushing the cap down into the fermenting vat of red wine must during maceration. Here's the story: Fermenting red wine generates a lot of unwanted heat. To cool the process down and extract as much tannin and flavor from the grape solids as possible, the cap—the layer of grape skins, pulp, pips (seeds), and other solids that naturally rise to the top of a fermenting vat—must be broken up periodically. You do this by pumping the must over the cap or by punching down the cap into the must. It's like using your spoon to push down and stir the hot chocolate mix that floats to the top of your mug.