American brand Proper Coffee has developed a machine that can take up to four hours to brew one pot of coffee – a process expected to improve the richness and reduce acidity.

The coffee machine, named Imperial Drip, slowly drips cold water through ground beans. It was inspired by Japanese cold-drip coffees, which are filtered over an extended period of time to give the beverage a more intense flavour.

Bill Abbe, founder of Proper Coffee, designed Imperial Drip with several variables intended to give coffee drinkers greater control over the strength and taste of each brew. The volume of water, coffee grounds, and speed that water drips can all be adjusted.

"This creates a whole new brewing concept and characteristic that allows for more water-to-coffee-grind contact over a longer period of time," Abbe told Dezeen.

While drinkers may have to wait longer for a cup of coffee, Abbe claims the cold drip method process produces a less acidic taste than its hot-brewed counterpart and has a more robust flavour and syrupy consistency that make it worth the wait.

"The slow drip process creates a unique characteristic with flavour and bean extortion that can't be accomplished with a normal hot coffee maker or espresso shot. After trying cold drip coffee for the first time, the user will enjoy the wait every time after," said Abbe.

The coffee-making apparatus consists of a laser-cut steel frame and two plastic brewing vessels. The nickel-plated steel structure stands 70 centimetres tall on a 23-by-23-centimetre base.

A platform mid-way up the structure holds a container for the coffee grounds, while the filtered coffee drips into a vessel below.

Abbe developed a recirculation pump that draws water from the vessel on the bottom tier, through a copper pipe on the outside of the structure, to drip above the coffee grounds at a rate of 40-45 drops per minute.

Each rotation takes between one and four hours and yields 450 millilitres of condensed coffee – enough for two or three servings.

Proper Coffee is currently seeking KickStarter funding to put Imperial Drip into production, and on International Coffee Day - 29 September - the project is short by just over $1,000. The company recently experienced crowdfunding success for an earlier model of the cold-drip coffee maker called Proper Coffee Cold Drips.

They hope to achieve enough backing to facilitate in-house, hand-assembled production of Imperial Drip at their Michigan site.