Siphon coffee was invented in the 1840s more or less simultaneously by a French housewife and Scottish marine engineer. It’s been refined many times, but a few principles hold true: It produces a delicate, tea-like cup of coffee; it can be quite persnickety; and it is, for our money, one of the coolest brew methods available.
After soaking your filter in a warm water bath for at least five minutes, drop it into the bottom of your siphon’s top component, or “hopper,” and hook to the bottom of the hopper’s glass tubing.
Fill your siphon’s bottom component, or “bulb,” with 300 grams of hot water (about a 12-oz. cup’s worth).
Insert the hopper, filter and all, into the bulb. You don't have to press too hard; just make sure it's securely and evenly in place. Position the entire assembly above your heat source.
While the water is heating, measure out between 20-25 grams of coffee and grind it just a little bit finer than you would for regular drip coffee.
Soon, the water in the bulb will begin boiling and rise up into the hopper. For some physics-related reason we don’t fully understand, a little bit will stay at the bottom. Don’t worry about this little bit.
Once the water has moved into the hopper, turn your heat source down so that the water is between 185-195 degrees F.
Add your coffee, and gently (but thoroughly) submerge it with a bamboo paddle or butter knife.
Let the coffee brew, undisturbed, for one minute and 10 seconds.
In one brisk motion, remove your siphon from its heat source and give it ten stirs with a bamboo paddle.
Your coffee should take another minute or so to draw downward and finally rest in the bulb. You'll know it's ready when a dome of grounds has formed at the top of the filter, and when the coffee at the bottom has begun to bubble at approximately the pace and strength of a kitten’s heartbeat.
Remove the hopper and serve. In order to guarantee the most complex cup, give the coffee a few minutes to cool.