How to Brew with Clear Slow Drip Coffee Brewer

By Hario USA | Published: 2026-10-30

Category: How-to Guides

Learn how to use the Hario Clear Slow Drip Coffee Brewer for a smooth, high-quality cold brew at home. Step-by-step instructions and tips included.

Quick answer

Brewing with the Hario Clear Slow Drip Coffee Brewer is a patient process: set the adjustable spout to drip cold water slowly over coffee grounds, then wait 3–12 hours for a smooth, concentrated cold brew.

Why slow drip instead of immersion?

Unlike immersion cold brewing (where grounds soak in water), slow drip passes water one drop at a time through a bed of coffee. This produces a cleaner cup with less bitterness and more aromatic clarity. The trade-off is time and setup precision—you can't rush it.

Choosing your grind size

For the Clear Slow Drip Brewer, use a medium-fine grind—similar to table salt. Too fine and the water will stall; too coarse and extraction will be weak. If you don't have a burr grinder, buy pre-ground coffee labeled for pour-over or drip, but note that pre-ground may not be consistent enough for optimal results.

Step-by-step brewing guide

Assemble and rinse: Place the acrylic tower on a stable surface. Rinse the glass carafe, brewing chamber, and metal filter with hot water (no soap on the filter—it holds flavors). A quick rinse warms the glass and removes any dust from storage.
Grind and load coffee: Grind 60–70 g of coffee to a medium-fine consistency. Add it to the brewing chamber and tap gently to level the bed. Do not tamp. Level grounds ensure even water distribution—tamping will clog the filter.
Set the water tank and adjust drip speed: Fill the upper water tank with cold, filtered water. Open the adjustable spout so water falls at 1–2 drops per second. Too fast? Close slightly. Too slow? Open a tiny bit. Aim for steady drops, not a stream—a stream will channel through the grounds and under-extract.
Wait and monitor: Let the brewer run for 3–12 hours at room temperature. Check every hour or two: the water level should drop steadily. If it stalls, the grind may be too fine or the filter is clogged. If dripping stops, gently stir the top layer of grounds with a chopstick to restart flow.
Serve and store: Once all water has passed through, remove the brewing chamber. Pour the cold brew over ice or dilute with water or milk (start with a 1:1 ratio). Refrigerate in the glass carafe for up to 5 days. The concentrate is strong—always taste before adding more water.

Product facts

"Clear" Slow Drip Coffee Brewer: The Clear Slow Drip Coffee Brewer uses single drops of cool water extracted through a metal filter and glass brewing elements in a clear acrylic tower. The metal filter lets more oils through than paper, so the brew is fuller-bodied while still being smooth.
"Clear" Slow Drip Coffee Brewer