Immersion dripper: the valve cone

History

The mechanism is described in a US patent granted on October 27, 1998, filed on November 4, 1997 by Yu-Mei Tien Lin, of Taipei, for the benefit of Peo-Wu Tien: an “infusion coffee maker” whose cone has a central hole at the bottom closed by a plug. Set on a table, the plug drops and the weight of the coffee holds it shut; set on a cup, the bottom is pushed upward, the plug is released and the coffee flows out. The patent cites three earlier devices, from 1956, 1991 and 1997 (source 1). The link between this patent and the Clever brand is asserted only by a forum; it has not been established by a primary document.

The Clever cone is designed and made by the Taiwanese company Absolutely Best Idea Development, known as Abid. A Pittsburgh journalist writes in January 2010 that it had appeared in cafés the previous summer, alongside the French press and the Chemex, and that the Myriade café in Montreal received its own as early as August 2008. The clear plastic body takes a standard no. 4 paper filter; the valve lets coffee flow only if it is pressed or if the cone is set on a cup (source 2).

The Japanese Hario, maker of the V60 cone, sells under the name Switch a heat-resistant glass “immersion dripper,” mounted on a silicone base, with a stainless steel ball and a resin control. Its product sheet, on the manufacturer's site since June 2019, explains that the powder is steeped and then the button is pressed to drain, “so that everyone can obtain a homogeneous extraction” (source 3, according to the manufacturer).

The motion

The paper filter is placed in the cone, valve closed, the grounds go in, the water is poured and you wait. To release the coffee, the cone is set on the cup or the button is pressed, and the liquid passes through the bed of grounds and the paper. At Chinatown Coffee in Washington, in 2010, they used 22 g of coffee for 11.5 ounces of water, about 340 mL, first poured 2 ounces to bloom the grounds for thirty seconds, then the rest, let it rest two minutes and the draining took a minute (source 2).

At Hario, the water is poured onto the powder in the paper, left to steep for a while, the button is pressed, and the flow continues to the end even when the finger is released (source 3). The usable capacity of the current model is 200 mL (source 3); the Clever gives 10 to 12 ounces, about 300 to 350 mL (source 2).

The settings

• GrindMedium; too coarse, it under-extracts, according to the roaster Scott Rao (source 2). No standardized particle size.
• Dose22 g for about 340 mL of water in the Chinatown Coffee recipe (source 2).
• Brew ratioAbout 1:15.5 in this recipe (source 2, calculation).
• TemperatureNot documented in the sources read.
• TimeThirty seconds of bloom, two minutes of steeping, one minute of draining (source 2).
• PressureAtmospheric during immersion, gravity during draining.

What it has going for it

• The contact time is set as with a French press and you get a cup without sediment as with a paper cone (source 2).
• The paper holds back the diterpenes, which pass into unfiltered coffees (source 4).
• The device is simple and compact; a café owner described it in 2010 as the “most accessible” coffee maker he had found (source 2).

What is held against it

• The cone loses a lot of heat during steeping, even covered, according to Scott Rao (source 2).
• Draining is slow and becomes more so when the fines migrate toward the paper and clog it; most users compensate with a grind that is too coarse, hence an under-extracted coffee (source 2).
• Capacity is small, one large cup or two small ones (sources 2 and 3).
• The last minute is no longer an immersion: the water passes through the bed of grounds, so the result also depends on the flow rate, which is not adjustable.

What it gives in the cup

The cup unites the two worlds: “the flavor and body come through, while keeping a very, very clean cup compared with a French press,” said the manager of Chinatown Coffee in 2010 (source 2). The paper holds back the oils loaded with diterpenes (source 4) and most of the fines.

The immersion phase obeys the same physics as the French press: concentration rises then levels off, faster if the water is hot, and at equilibrium the yield varies little with the grind (source 5). The cone, which loses its heat (source 2), therefore extracts more slowly than an insulated vessel. No measurement of concentration or yield specific to these devices was found in a primary source.

Anecdotes

• The café that made the Clever cone known in North America, Myriade in Montreal, had already moved on by 2010: its co-owner Scott Rao criticized its loss of heat and its too narrow opening, and was preparing his own coffee maker (source 2).
• In Washington, the manager of Chinatown Coffee noticed that each time a Clever cone was prepared, the next customer asked what it was, and often ordered it (source 2).

The sources for this sheet

1. Yu-Mei Tien Lin (assignee Peo-Wu Tien), US patent 5,826,493, “Infusion coffee maker,” filed November 4, 1997, granted October 27, 1998 · online · primary · reading: front page, abstract and drawing
2. China Millman, “What's Brewing: This manual coffee maker's valve lets you control extraction time,” Pittsburgh Post-Gazette, January 21, 2010 · online · press
3. Hario, product sheet “浸漬式ドリッパー スイッチ” (Switch immersion dripper), SSD-200-B, hario.co.jp, Internet Archive capture of December 7, 2019 (first capture of the address: June 11, 2019) · online · manufacturer
4. R. Urgert, M. B. Katan, “The cholesterol-raising factor from coffee beans,” Annual Review of Nutrition, 17, 1997, p. 305-324, doi:10.1146/annurev.nutr.17.1.305 · online · secondary · reading: abstract only (PubMed)
5. J. Liang, K. C. Chan, W. D. Ristenpart, “An equilibrium desorption model for the strength and extraction yield of full immersion brewed coffee,” Scientific Reports, 11, 2021, 6904, doi:10.1038/s41598-021-85787-1 · online · primary