Zach Mazrim - Expert review of the Delter Cold Drip
The Delter Cold Drip has made one of the least labor-intensive methods of coffee preparation even more accessible to the coffee aficionado. For starters it is necessary to differentiate cold drip from cold brew. Making cold brew coffee involves a straightforward process of immersing coffee grinds in water for an extended period of time. This is typically done in a colder environment like a refrigerator. At the end of the brewing process, you simply need to filter out the grinds, leaving the liquid coffee to enjoy. Cold drip, or sometimes called ice drip, utilizes a different method of extraction called infusion. As cold water drips over the bed of coffee grinds, it dissolves compounds in the coffee and relies on gravity to pull it through into a carafe below. The same concept of immersion versus infusion is seen in preparing coffee with hot water in a French press compared to the Origin brewer or another pourover device like a v60. To recap, cold drip utilizes an infusion method of extraction over a significantly longer timeline.
So how does the Delter Cold Drip stand apart from other brewers? Let’s look at its design, ease of use, and the fundamental science that informed its design.
While the Delter Press, at first glance, may look similar to the iconic Aeropress, the similarities end with the visuals. The Delter Press isn’t actually a “press pot” in the traditional sense and the plunger doesn’t plunge so much as it builds pressure to open the unique jet seal, allowing water to pass through. When brewing with the Delter, you will discover the coffee more closely resembles pour-over in terms of body, mouthfeel, and acidity. This is due to the jet seal releasing water evenly through the 19 holes onto grinds in a low-pressure, slow and controlled manner as the plunger is pressed down. Here we see the integrated agitation control solution highlighted. Water is uniformly injected into the coffee bed. Where pour-over agitation solutions are found in additional external instruments (i.e. Melodrip), the Delter Press incorporates the concept into the design itself.
The Delter has a much lower profile compared with the extremely tall, ornate, glass apparatuses seen at some cafes. While flashy, those ice drippers typically require more attention (constant addition of ice) and designated counter space. The Delter Cold Drip distinguishes itself already. While it accommodates small ice cubes in the reservoirs, it is designed to be used with cold water and is short enough to easily fit into a refrigerator for the entirety of the brewing process. Already the space requirement has been eliminated. The Delter also has a larger percentage of plastic components, making it practical for daily use at home or in the office. Glassware is great but prone to breakage. The only glass component of the Delter is the storage pitcher, necessary for preventing coffee residue and oils from embedding into plastic.
The design lends itself to ease of use. There are only a few parts that constitute the overall dripper- three drip trays, the coffee basket, mesh filter, and glass pitcher. These pieces all fit together smoothly and are easy to clean. The coffee basket is wide enough to be used without a funnel, and the drip trays display 200ml volumetric markings, again making the Delter easy to use without a scale. The maximum capacity is 600ml, making an ideal amount of coffee for several days to one week. It is simple enough to scale down, however, by simply removing one or two of the drip trays at the outset. Once the coffee grinds are added to the basket, cold water is poured into the drip trays one by one and the whole apparatus is placed in the refrigerator to be left alone until brewing is complete- roughly three to four hours.
Why does the Delter Cold Drip require so much less attention than other ice drippers?
To answer this question, let us explore the underlying physics. Traditional ice drippers require ice cubes to be placed in a top chamber where they melt into liquid water. This water then travels through a valve. The valve restricts the flow rate of water to release steady droplets into the brewing chamber where the coffee grinds are. Valves, however, need constant adjustment to maintain the desired flow rate. This is due to pressure fluctuation from the weight of the water column above the valve. As more water passes through, there is a comparatively smaller.
Zach Mazrim
Sub Editor at Cafe Culture China