The way it works is pretty cool, because you use hand pressure to force hot water through coffee, instead of letting gravity do its thing. The AeroPress uses air pressure, forcing the water through the coffee bed when you place the plastic plunger into the chamber, and push it down. The AeroPress is a simple device, with a chamber made from tough, heat-resistant plastic. A plunger with a rubber end fits into the top of the chamber and forms an airtight seal. The base of the cylinder screws off, but holds a paper filter and can screw securely in place. The pressure it creates is unique to any other brewing device out there, and it mimics the pressure of an espresso machine. Espresso machines push hot water through the coffee at 9 bars of barometric pressure, for a very intense and concentrated extraction. An Aeropress uses .35-.75 bars, which is low in comparison to an espresso machine, but still more than letting gravity take control. This allows an intense coffee that rides the lie between an espresso and a drip coffee.
The AeroPress is a unique brewer because you can use an extra fine, fine, or medium grind for your recipe, and each of them works equally well! The grind size will ultimately affect the flavors that you’re trying to extract from the coffee. If you want a very intense and concentrated coffee, use a finer grind. This will mimic espresso as closely as possible, and the finer grind size will create a more intense and powerful flavor. The more coarse the grind size, the more mellow the flavor, which allows space for all the different flavors to be expressed.
The paper filters needed for an Aeropress can be reused for those of us who are environmentally minded. However, the more they’re used, the less effective they end up being. They could also potentially hold on to some flavors from the previous coffees they filtered, so you should keep that in mind when reusing your filter. If creating paper waste is something you’d like to avoid, there are stainless steel disc filters specifically made for AeroPresses. Stainless steel is easy to clean, and coffee oils and residue don’t cling to it. Just be careful not to accidentally throw it away when you’re clearing out your coffee grinds!