Coffee in a Vacuum
Today we’re going to check out a somewhat obscure brewing method: the vacuum pot! This type of brewing was popular in the early part of the twentieth century, before paper filters were invented. It makes a very clean, bright cup of coffee with pronounced body and little to no sediment.
The design is elegant, the concept brilliant in its simplicity. The basic setup consists of two stacked glass pots. Water is brought to a boil in the lower pot, while ground coffee is placed in the top vessel. Increasing vapor pressure forces the water from the bottom pot into the upper pot to begin the brewing process. The lower pot is kept hot during the extraction to keep the pressure high enough to support the water in the top pot. When the brew is ready, it’s taken off the heat and allowed to cool. As the hot steam condenses back into liquid water, gravity and the pressure difference between the two pots pulls the water down through the grounds and the filter into the lower vessel. Your brew is ready to pour!
Heat sources can be an interesting challenge for this type of brewing. Options for heating may be an alcohol spirit lamp, gas burner, camp stove, micro butane burner, or fondue stove. I prefer a single burner camp stove capable of fine flame adjustment. It also takes a little more finesse in terms of monitoring the brewing process so I consider this more of a "weekend" brew than a 6:00am Monday morning activity.
Mastering the art of vacuum pot brewing can be tricky, but the reward is a distinctive, flavorful cup. It’s a method well suited to showcase the delicate flavors of some coffees, like the fruity Ethiopians or flowery Central Americans. It may present a lighter body if you’re used to the weighty feel of coffee from a French Press, or it might be just the brew you’ve been looking for.