Ratio Four Coffee Maker

Before first use, run a water-only brew cycle to rinse the machine. Fill the removable Tritan water tank to the desired volume (5–20oz), place a paper filter in the basket, and press the single start button. Discard the rinse water.

The Ratio Four uses a mechanical pump and 1200W aluminum flow-through heater to deliver water at 195–203°F (91–95°C) — within the SCA gold cup standard. The showerhead distributes water evenly across the grounds. There are no programmable settings, timers, or displays — just one touch-sensitive start button.

Filters: The Ratio Four uses standard 8–12 cup flat-bottom basket paper filters — available at most grocery stores. It also works with Kalita 185-size filters. Do not use cone-shaped filters.

The removable water tank sits on a separate base that can be positioned wherever is most convenient. Fill it at the sink with 5–20oz of cold, filtered water. Tank markings show ounce volume. For precise measurement, place the tank on a scale and weigh your water.

One-Button Brewing

Add water to the tank, add your ground coffee to the filter basket (see ratio below), place the carafe under the showerhead, and press the touch-sensitive start button. The Four automatically runs a bloom phase — it delivers a burst of hot water over the grounds, then pauses for 15 seconds to allow CO₂ to release — before delivering the remaining water in a continuous pour. Total brew time is approximately 4 minutes.

Dose and Ratio

Use approximately 1:15–1:17 coffee to water by weight. For 300ml of water (approximately 10oz), use 18–20g of ground coffee. The Four brews 5–20oz per batch — ideal for one generous mug or two standard cups. Scale your dose accordingly. For batch reproducibility, weigh both your coffee and water.

Grind

Use a medium grind — coarser than espresso, similar to or slightly finer than a standard drip machine. Start at medium and adjust based on taste: if the cup is sour or thin, grind finer; if bitter or over-extracted, grind coarser.

Carafe and Serving

The smoke-tinted hand-blown glass carafe is a display of craftsmanship — handle it with care. The carafe has a lid for heat retention after brewing. Pour immediately for the best flavor; unlike machines with hot plates, the Ratio Four has no warming element. Brewed coffee is best consumed within 20–30 minutes for optimal flavor.

Versatility

The Ratio Four's showerhead is positioned to work with many different dripper styles placed on a mug or server below. If you want to use your V60, Wave, or other manual dripper, position it below the showerhead in place of the carafe.

After Each Use

Remove and discard the paper filter. Rinse the filter basket under hot water. Hand-wash the glass carafe with mild dish soap and a soft cloth — do not use abrasive sponges. Rinse thoroughly. The carafe is not dishwasher safe.

Monthly — Descaling

Run a descale cycle when you notice mineral buildup or slower brewing. Use a citric acid-based coffee maker descaler — mix per the descaler instructions and run a full brew cycle. Follow with 2–3 cycles of fresh water to fully rinse. Do not use vinegar in the Ratio Four — it can damage internal seals over time.

Water Tank

Rinse the Tritan water tank weekly with warm water. The tank is hand-wash only — do not put in dishwasher.

Brew Running Slowly / Overflow

Grind may be too fine, causing the filter to clog. Adjust coarser. Also ensure the filter is fully seated flat in the basket without folding. Do not overfill with coffee grounds beyond the basket capacity.

Coffee Tastes Weak

Increase coffee dose or grind finer. Ensure you're using a medium grind, not a coarse one meant for French press.

Bloom Not Visible

Coffee may be older (low CO₂ = minimal bloom). This is normal — stale coffee blooms less. The machine still runs the full bloom pause regardless.

Machine Not Starting

Ensure the water tank is properly seated on its base and has water above the minimum line. Confirm the power cord is fully connected.