Pump tube: steam under the domed foot pushes hot water up itGlass knob: each splash is one perkA percolator has no pump and no filter paper: the heat does the lifting. 1.2 litres of water sit in the pot and 70 g of coarse coffee in a drilled basket held above the water. The hot plate heats the pot floor, and the water trapped under the domed foot boils first. Each steam bubble shoves a slug of hot water up the thin tube, where it hits the glass knob (the perk you can see and hear), falls on the spreader, rains through the grounds and drips back into the pot. The same liquid goes round again and again, a little darker every time, and because it runs close to boiling (about 96 °C) it can taste harsh. A brew is about 8 minutes from the first perk. The page plays 40 times faster than life, but each perk is kept slow enough to see.