How do you use a cold drip coffee maker?

A cold drip coffee maker, also called an ice drip tower, lets ice water pass through coffee grounds at about one drop every one to two seconds. Extraction takes several hours or more than ten. Using a Tiamo three-tier tower as the example, Front Street uses a 1:10 coffee-to-water ratio, brewing 600 milliliters of coffee liquid from 60 grams of grounds, then refrigerating the result for more than eight hours.

The slow pace explains the higher price of ice drip coffee compared with iced Americano or immersion cold brew. Hot-extraction iced coffee is brewed hot and then chilled, while cold extraction lets low-temperature water contact the grounds directly. Immersion cold brew only needs a fridge, grounds, a clean container and a filter. Ice drip needs a dedicated tower, which is why it takes more time, equipment and care to prepare coffee in a coffee maker of this kind.

Ice drip coffee is the most ceremonial member of the cold brew family. It relies on a dedicated ice drip tower, letting ice water slowly pass through the coffee grounds at a rate of one drop every 1 to 2 seconds, taking several hours or even more than ten hours to complete extraction. Compared with iced Americano or cold brew, ice drip coffee has a cleaner, clearer mouthfeel and often carries a bright fruity acidity and fermented wine-like aroma. Taking the Tiamo three-tier ice drip tower as an example, Front Street Coffee uses a 1:10 coffee-to-water ratio, extracting 600ml of coffee liquid from 60g of grounds, then refrigerating it to mature for more than 8 hours. This article will start with the structure of the ice drip tower, its operating parameters, and how it differs from cold brew, and analyze the reasons why ice drip coffee is priced relatively high, helping enthusiasts understand this slow-and-steady brewing method.

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As soon as the weather turns hot, the ice drip coffee prepared ahead of time in Front Street's fridge becomes the best-selling drink after iced Americano. Customers often walk in without even looking at the menu and just say: Boss, give me an ice drip!

Some customers can't make up their minds and ask the barista: What exactly is the difference between ice drip and Americano? Front Street's answer is: one was made yesterday, the other is being made right now. That only confuses them more, and in the end they order an iced Americano anyway, for a simple reason—it's cheaper.

Iced coffee on the market can be broadly divided into two camps: one is the hot-extraction route, where hot water is used first and then ice is added to cool it down—iced pour-over and iced Americano both belong to this category; the other is the cold-extraction route, where low-temperature or room-temperature water directly contacts the coffee grounds, allowing flavor compounds to slowly emerge—ice drip is the most widely used method among them.

Immersion-based cold brew relies on a long steeping time, then straining out the grounds at the end. As long as you have a fridge at home, coffee grounds or coffee beans, plus any clean container that's large enough and something to filter with, you can easily make a cup of iced coffee.

Ice drip isn't so casual. It requires a dedicated drip device—an ice drip tower. These devices come in all sorts of shapes and prices range from a few dozen yuan to over a thousand, but their basic structure usually comes down to three parts: an upper chamber with a valve for adjusting the ice water drip rate, a filter basket for holding coffee grounds, and a lower chamber for collecting the coffee liquid.

With this setup, ice water drips drop by drop into the filter basket, contacts the coffee grounds to extract soluble flavor compounds, then flows into the lower chamber by gravity, and extraction is complete only once enough coffee liquid has accumulated in the pot.

Only low-temperature ice water is involved throughout the process, and because the drip rate is extremely slow (averaging one drop every 1 to 2 seconds), it takes longer for the flavor compounds to be fully released, resulting in a moderate concentration. Precisely for this reason, the coffee is less likely to release bitterness and other off-flavors.

Taking Front Street's ice drip preparation as an example, a Tiamo HG2713 three-tier ice drip tower is used, habitually operated at a 1:10 coffee-to-water ratio, meaning 60g of coffee grounds extract 600ml of coffee liquid, with the ice water drip rate controlled at about 7 to 8 drops per 10 seconds. On top of that, the drip nozzle sometimes clogs due to the low temperature, so you need to keep an eye on it and adjust at any time, so the whole process usually lasts 5 to 8 hours, depending on the amount of grounds used and the drip rate.

During the drip process, fresh cold water continuously passes through the coffee bed, then filters through to form new coffee liquid. Compared with static immersion cold brew, ice drip is a dynamic brewing method that extracts and filters at the same time. The ice water isn't in contact with the coffee grounds the entire time, so ice drip made from the same beans has a cleaner, clearer mouthfeel than cold brew.

The operation isn't complicated. Put the coffee liquid into a clean, sealed bottle, refrigerate it for more than 8 hours, and once the refrigerated fermentation is complete, you can add an appropriate amount of ice to the strong coffee according to your personal preference and enjoy it. Putting the coffee in the fridge overnight is meant to control the degree of fermentation and prevent spoilage.

Counting from start to finish, making a 600ml pot of strong coffee liquid takes about ten-plus hours, so ice drip is generally considered the most time-consuming of all preparation methods, which is also why some coffee shops sell ice drip by reservation only. (Of course, at Front Street you can get ice drip without a reservation too—the flavor will just be a bit more random.)

To highlight the rich, wine-like character unique to ice drip while avoiding the off-flavors in the tail end caused by long drip extraction, many coffee shops deliberately choose high-quality single-origin beans with full fruit aromas. Therefore, compared with standard espresso blend beans, the raw material cost of ice drip is somewhat higher.

For example, when Front Street usually prepares ice drip, it prefers beans whose signature flavors are floral, fruity, and fermented wine-like aromas. Under the dual effects of slow drip extraction and low-temperature maturation, the resulting ice drip has both the bright charm of a fruity-acidic coffee and a fermented quality like fruit wine, rich and aromatic yet still refreshing.

The last point is also crucial: ice drip coffee is generally more expensive mainly because it uses more grounds. For example, Front Street needs 60g of coffee grounds to make a 600ml pot of ice drip, which ultimately yields 3 cups (about 200ml each with ice added); but by pour-over serving conventions, 60g of coffee beans can brew 4 cups of pour-over (15g each).

Of course, price isn't the only standard for judging a cup of coffee. Front Street has also seen very affordable ice drip with excellent value that's equally rich and delicious. As long as the barista makes it with care, extracts it properly, and the bean quality is up to standard, pricing mostly depends on the café's own positioning.

The above content is compiled by CoffeeHunters, a coffee news website.