What is immersion brewing? Immersion vs pour-over explained

How is immersion different from percolation?

The key difference is the water doing the extracting. Coffee ad Astra puts it plainly: "a percolation extracts coffee with clean water, and an immersion extracts coffee with water that is gradually becoming more and more concentrated."

In an immersion, the water fills up with dissolved coffee as it sits. Coffee ad Astra says this slows extraction as the water nears saturation. In a percolation, fresh water keeps replacing the brewed liquid, so extraction stays fast.

Why does immersion coffee taste different?

Because it extracts a different balance of compounds. Using a toy model of 30 made-up compounds, Coffee ad Astra found that an immersion brew's chemistry closely follows the bean's own makeup.

A percolation brew over-represents the compounds that dissolve fastest. So a V60 and a French press made with the same coffee can taste like different coffees. Neither is wrong.

The filter adds a second difference. Many immersion brewers, like the French press, use metal mesh. Perfect Daily Grind says that leaves more oils in the cup and a fuller body.

Which brewers are immersion brewers?

The French press is the classic one. Wikipedia describes steeping coarse grounds in hot water, then pressing a mesh plunger down to separate them.

Standard cold brew is also immersion. Wikipedia says coarse grounds soak in water for 12 to 24 hours. It notes that slow-drip, or Kyoto-style, cold brew is a different process, where water drips through the grounds over many hours.

Cupping, the way professionals taste coffee side by side, also steeps grounds directly in hot water. See cupping.

What grind size does immersion brewing need?

Usually coarser than pour-over, because the grounds sit in water for minutes or hours. Wikipedia recommends a French press grind "about the consistency of cooking salt."

Cold brew goes coarse too. Stumptown recommends a grind "similar to what you'd use for a French press." It says coarser particles strain more easily and resist over-extraction.

In immersion, time is set by you, not by flow rate. So grind size mainly controls how fast extraction happens and how much sediment gets through. For starting points on your grinder, see immersion grind settings, or check a number with the grind converter.

Is immersion brewing more forgiving?

In one sense, yes: it slows itself down. Stumptown says cold brew reaches an equilibrium toward the end of the steep. Going a few hours over will not ruin a batch.

It still has limits. Stumptown warns against steeping past 20 to 24 hours, which can bring bitter, woody notes. Wikipedia notes that French press coffee left on the grounds may turn astringent and bitter.

If you want step-by-step recipes, our AeroPress vs French press comparison and French press brewing guide cover the details. For the slow, cold version, see cold brew.