When it comes to choosing a coffeemaker, you have a lot of options: drip, percolator, French press, or vacuum coffeemaker, also called a siphon coffeemaker. The vacuum coffeemaker is reputed to have excellent flavor, but comes with numerous disadvantages that have hurt their popularity.
Mechanism of Brewing
The principle of brewing coffee is simple: run hot water over coffee grounds until it tastes right. There are many ways to do this and many evolving machines to make it easier. The drip coffeemaker drips or sprays water over grounds in a basket, which then drips into a carafe for serving.
The percolator boils water, then forces it through a tube where it circulates over the grounds until ready to pour. The French press uses a plunger to immerse grounds in hot water, then decants from the same container.
The vacuum brewer is much more complex than any of these. It uses a two-chamber vessel, similar to 2 glass carafes on top of one another. You heat water in a lower vessel until expansion forces the contents through a narrow tube into an upper vessel that contains ground coffee.
When the lower vessel is empty and sufficient brewing time has elapsed, you remove the coffeemaker from the heat. The resulting vacuum draws the brewed coffee back through a strainer into the lower chamber from which it can be decanted.
The main advantage of the vacuum system is the coffee it produces, which is clean, crisp, and smooth compared to other brewing systems. In fact, it is the preferred method of brewing coffee in Japan, where vacuum coffeemakers outsell standard drip models.
On the other hand, the process has long been criticized as being too complex. It demands that you constantly monitor the system, watching it as it heats, timing the brewing and removing the heat.
Other disadvantages include:
Cleaning a vacuum brewer takes more effort than cleaning a drip coffeemaker.
Automatic vacuum brewers are not widely available, making the use of a vacuum brewer much more time and labor-intensive than other methods.
The quality differential between vacuum-brewed and drip coffee is not generally regarded as large enough to justify the extra effort.
Great for Camping
While home vacuum systems are still available new, and some vac pots or siphon systems can be found in antique stores, it is unlikely that they will ever attain the popularity of other more modern systems.
It will, however, remain a viable tool for backpackers, as it is an extremely effective way to make a freshly-brewed cup of coffee over a camp stove or fire. For the coffee aficionado who doesn’t want to leave their brew at home, the vac pot is still a good choice.