How Do the 7 Steps to Make Coffee Apply to Ice Drip?

Ice drip coffee depends on four core variables: grind size, drip speed, extraction ratio, and aging time. Unlike cold brew, which simply soaks grounds in water and is filtered hours later, ice drip uses an ice drip tower with three layers holding ice water, coffee grounds, and the finished liquid, extracting drop by drop.

A standard ice drip needs a valve at the bottom of the upper container to control the water flow, keeping the grounds under continuous extraction until the target amount is reached or the ice water runs out. The liquid is then refrigerated and aged to develop its smooth, layered taste. Cold brew is simpler and can be made at home with grounds, water, and time.

Ice drip coffee, with its lengthy brewing process and unique flavor layers, has become the representative of "slow work produces fine results" in the hearts of many coffee enthusiasts. Unlike cold brew, ice drip relies on a specialized device, extracting via ice water dripping one drop at a time through the coffee grounds, followed by refrigerated fermentation and aging to present a rich and smooth taste. This article, based on Front Street's practical experience, breaks down in detail the four core variables of ice drip coffee—grind size, drip speed, extraction ratio, and aging time—and provides specific parameter suggestions to help you make a standard ice drip coffee at home.

"Excuse me, do you have ice drip coffee?"

"Yes, today's ice drip is..."

"How is it ready so quickly?"

"Due to time constraints, the ice drip is prepared in advance and kept in the fridge."

"So how long does it take to make a cup of ice drip coffee?"

This is a conversation that occasionally occurs at Front Street stores. Regarding ice drip coffee, aside from the often-compared point of "being more expensive," its lengthy preparation time adds a lot of mystery to this type of coffee.

Although both are coffees extracted under low-temperature water, the preparation steps and principles of ice drip and cold brew are completely different. Cold brew, or cold immersion, is simple and straightforward: just mix coffee grounds with water, refrigerate for several hours, then filter out the grounds, and it's all done. So as long as you have coffee beans (grounds), anyone can make cold brew at home.

Ice drip is the exact opposite. A standard serving of ice drip coffee first requires a specific device—an ice drip tower, with three layers containing ice water, coffee grounds, and the dripped coffee liquid from top to bottom, respectively. It is a continuous multi-extraction method.

Moreover, from the name, it's not hard to see that ice drip coffee not only emphasizes "ice" but also requires "dripping" for extraction. Therefore, the upper container holding the ice water must be equipped with a valve at the bottom to control the water flow drip, ensuring the coffee is always in an extraction state. Finally, until the coffee liquid reaches the target extraction amount, or all the ice water has dripped into the coffee grounds, the extraction is complete. However, at this point, the coffee liquid is not yet ready to drink; it needs further refrigeration for fermentation and aging to develop a rich, smooth, and layered taste.

In summary, to make standard ice drip coffee, we not only need specialized equipment but also must constantly monitor the water drip to maintain stable extraction, grasp various parameters and details, and wait through a long fermentation process. Clearly, compared to "hands-on" cold brew, ice drip coffee has many more complex preparation elements, which is the main reason few people choose to make ice drip at home.

Front Street often mentions in articles that different water temperatures can brew coffees with different flavors, and at low temperatures, the astringent substances in coffee are less likely to be released. Like pour-over, ice drip is also a drip-filter coffee, except it uses ice water below 5°C as the solvent, which can be understood as low-temperature drip-filter coffee.

Based on Front Street's experience, the preparation time of ice drip is mainly influenced by the following four factors: drip speed, coffee grind size, extraction ratio, and aging time.

1. Grind size of coffee grounds

Two points to note about the coarseness of coffee grounds: if too coarse, the powder layer forms less resistance, and water more easily penetrates into the lower pot. With low extraction efficiency of cold water, this results in weak coffee with insufficient flavor. If too fine, it's also not good; greater resistance can easily cause clogging and water accumulation, and prolonged soaking brings out bitterness and astringency.

For controlling ice drip grind size, Front Street uses a No. 20 (0.85mm) standard sieve for calibration. The grind sizes for various common extraction methods, from fine to coarse, are as follows: ice drip (cold brew) > pour-over (siphon) 80% > American drip 75-80% > cupping 70-75% > French press 65-70%. Therefore, the grind size for ice drip coffee should be slightly finer than pour-over, with a passing rate of about 83-85%.

2. Drip speed of water

Throughout the drip process, new cold water continuously passes through the coffee bed and filters to form new coffee liquid. Compared to static cold immersion, ice drip is a dynamic brewing method that extracts and filters simultaneously. So to prevent extraction interruption, we must ensure water drips uniformly onto the coffee bed to obtain a cup of ice drip coffee with both concentration and taste.

Thus, controlling the drip speed is crucial in making ice drip coffee. If the drip speed is too fast, under-extraction occurs, making the coffee weak and lacking aroma; conversely, if too slow, it causes fermentation, leading to unpleasant sourness or off-flavors.

According to Front Street's experiments, when using light-roast beans, the valve can be adjusted to a faster state of 7 drops per 10 seconds to highlight the light floral and fruity notes, such as Front Street Red Cherry and Front Street Little Tomato; when using medium-roast beans, like Front Street Sidra and Front Street Strawberry Candy, Front Street recommends a slower flow of 5 drops per 10 seconds, which gives the final coffee a rounder body and fermented feel.

3. Extraction ratio

The ratio of ice drip not only affects preparation time but, more importantly, determines the coffee's concentration and extraction yield. Considering the coffee will eventually be served with ice to maintain low temperature, Front Street habitually uses 1:10 for ice drip. For those who prefer a refreshing taste, Front Street recommends 1:12 to 1:14, making the iced coffee more suitable for direct consumption.

4. Aging time

Many people know that even ice drip extracted under the same conditions will taste quite different depending on the number of storage days.

A freshly made pot of ice drip placed in the fridge allows the substances in the coffee to undergo a slow, controlled fermentation. After several hours of settling, the coffee's taste becomes transparent and mellow; on days 3 to 5, the fermented flavor of ice drip is most prominent; starting from day 6, the flavor substances dissolved in water continue to change, some aromas dissipate, and the acidity is no longer bright. Therefore, considering both flavor experience and health safety, Front Street recommends drinking the prepared ice drip coffee within 5 days (counting from the production day) for the best experience.

How long does it take to make a cup of ice drip coffee?

According to Front Street's specification of about 200ml for a cup of Red Cherry ice drip coffee, when using a 1:10 coffee-to-water ratio, 20g of coffee grounds are needed, corresponding to 240g of ice water (coffee grounds absorb twice their weight in water), with a valve flow of 7 drops per 10 seconds, taking about 2.5 hours to fully drip.

But since we know ice drip is inefficient, most of the time we don't make just one cup but "as much as it can hold." For the device used at Front Street stores, the lower pot can hold up to about 650ml of coffee liquid, so each batch makes three cups, using 60g of grounds to drip 600g of coffee liquid, with the valve at 7 drops per 10 seconds, taking about 7 hours for the drip. Finally, the coffee liquid is refrigerated overnight, ready to sell the next day.

So when asked how long it takes to make a cup of ice drip coffee, saying a day and a night doesn't seem wrong.

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