Siphon coffee brewing has earned a fair amount of prestige in the specialty coffee world. The process is visually fascinating, the mechanics bring out the scientist in all of us, and the results are delicious.
Rich with vibrant aromas, crisp with a mild acidity, smooth with coffee oils, and without any microscopic coffee grounds, siphon coffee is some of the most prized coffee in the world.
Brewing siphon coffee at home is the most affordable way to experience the process, appreciate the physics, and taste the rich reward. While it may appear too complicated to be worth learning about, it’s actually quite simple. With a hint of effort and a bit of patience, you’ll be a siphon coffee rockstar in no time. Let me show you how it works.
How Siphon Coffee Brewers Work
Siphon coffee brewing came into the world around the 1840’s. There seem to be two people that came up with the idea independently: a French woman and a Scottish marine engineer.
During this time it was believed that fine coffee grounds always produced better flavor than coarse grounds. However, there was a limit to how finely coffee could be ground. Brewed coffee wouldn’t drain through if the grounds were too fine.
The creative solution? Create a siphon to pull the brewed liquid through. Instead of relying on gravity alone to drain the liquid, a siphon brewer would create a vacuum that would suck the liquid through, allowing coffee enthusiasts of the day to explore using finer and finer grind sizes.
Here’s how it works in more detail:
A lower bulb full of clean water is suspended above a heat source (often a butane or alcohol burner). The heat causes the water to boil and rise.
Fastened tightly above the lower bulb is the upper chamber. This chamber has a tube that descends into the lower bulb, which creates a passageway for the water vapors to rise through.
Attached to the opening in the upper chamber is a cloth coffee filter, which is topped with finely ground coffee. As the water vapor passes through the filter and comes in contact with cooler air, it becomes a liquid again. Then the coffee grounds are added to initiate brewing.
Once the brewing is complete, the heat source is removed from below the lower bulb. There’s now a contrast in temperature between the bulb and the upper chamber, which creates a vacuum and causes the brewed coffee to begin draining rapidly.
The liquid coffee is drawn down via a vacuum and gravity as the grounds stay in the upper chamber with the cloth filter. The two parts can be separated and the coffee poured.
The Easy Guide to Brewing Siphon Coffee
Even if you’re new to manually brewed coffee, siphon coffee is something you can brew at home. Here’s how easy it can be.
Here’s the gear you need to get started:
A siphon coffee maker
A heat source (often included with the siphon)
A coffee grinder
A gram scale
A non-metal spoon or paddle
A timer or stopwatch
In this scenario, we’ll say you’re using a standard 3 cup siphon. As a general rule, use about 60g of coffee per 1 liter of water. For a siphon of this size, that means you’ll want to use about 24g of coffee and 400 ml of water (which also equals 400g of water, if you’re using your gram scale to measure the water also).
Step 1 – Pour 400 ml of near-boiling water into the lower bulb of your siphon, attach the cloth filter to the upper chamber, and stack the two pieces tightly and evenly so that a seal is created.
Step 2 – Grind 22g of coffee beans at a fine to medium-fine setting and set to the side. Then, slide your heat source under the lower bulb.
Step 3 – Turn the heat on high. The water will boil and rise to the upper chamber. For a physics reason that’s not understood, a small amount of water will remain the lower bulb.
Step 4 – Start a timer and pour your grounds into the upper chamber and stir gently with a non-metal spoon or paddle to saturate all the grounds. If grounds clump together and form a crust at the water surface, gently submerge them.
Step 5 – After 1 minute of brewing, turn off your heat source and move it away from the lower bulb. After a brief delay, the brewed coffee will be sucked down into the lower chamber. Draining should take 30-60 seconds.
Step 6 – Allow the siphon to sit for 3-5 minutes as it cools. Then, set the upper chamber aside, pour your siphon coffee into a mug, and enjoy.
Troubleshooting Your Brew
While brewing great siphon coffee isn’t difficult, there are a few easily-made mistakes that could throw off your brew. Here are a few of those simple errors and how to fix them.
Your coffee drains too quickly or slowly. A draining speed issue is almost certainly a grind size issue. You either ground your beans too fine, causing the draining to stall or clog, or too coarse, causing the water to drain almost immediately. Grind coarser for a quicker drain and finer for a slower drain next time.
Your coffee tastes light or weak. This likely indicates under extraction, which means you need to pull more things out of the grounds and put them into the water. Add another 15 seconds to your brew next time.
Your coffee tastes overpowering or bitter. Sounds like you pulled too much from the grounds, creating an over extracted flavor. Reduce the brew time by 15 seconds or so next time.