"Do you have cold brew drip coffee?"

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

"How was it made so quickly?"

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

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

This is a conversation that occasionally happens at Front Street stores. Regarding cold drip coffee, aside from the fact that it is "more expensive," which often sparks various comparisons, its lengthy preparation time also adds a lot of mystery to this type of coffee.

Although both are coffees extracted under low-temperature water, the production steps and principles of cold drip and cold brew can be said to be completely different. Cold brew, namely cold extraction, is simple and straightforward: just mix coffee grounds with water, then refrigerate for several hours, and filter out the coffee grounds to complete the process. Therefore, as long as you have coffee beans (grounds), anyone can make cold brew at home.

Cold drip is exactly the opposite. A standard serving of cold drip coffee first requires a specific set of equipment—a cold drip brewer. The container has three layers: the top holds ice water, the middle holds coffee grounds, and the bottom collects the dripped coffee liquid. It is a continuous multi-extraction coffee method.

Furthermore, from the name, it's not hard to see that cold drip coffee not only emphasizes "cold" but also requires extraction by "dripping." Therefore, the upper pot holding the ice water must be equipped with a valve that controls the dripping of water to ensure the coffee is constantly in a state of extraction.Finally, when the coffee liquid reaches the target extraction amount, or when all the ice water has dripped through the coffee grounds, the extraction is complete. However, at this point, the coffee liquid is not ready to drink directly; it needs to be refrigerated for a period to ferment and mature, so that the taste becomes rich, smooth, and layered.

In summary, to make standard cold drip coffee, we not only need specialized equipment but also must constantly monitor the water droplets to maintain stable extraction, grasp various parameters and details, and wait through a long fermentation process. Obviously, compared to the "anyone can do it" cold brew, cold drip coffee has many more complicated production elements, which is the main reason why few people choose to make cold 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, cold drip is also a drip coffee, except it uses ice water below 5°C as the solvent, which can be understood as low-temperature drip coffee.

Based on Front Street's experience, the production time of cold drip is mainly affected by the following four factors: water dripping speed, coffee grind size, extraction ratio, andmaturation time.

1. Coffee grind size

When grinding coffee, two points need attention: if the grind is too coarse, the resistance formed by the powder layer is smaller, and water passes through more easily into the lower pot. Under low extraction efficiency with cold water, this results in weak coffee with insufficient flavor. If the grind is too fine, the increased resistance can easily cause clogging and water accumulation, and prolonged soaking will bring out bitter and astringent flavors.

For cold 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: cold drip (cold brew) > pour-over (siphon) 80% > American drip 75-80% > cupping 70-75% > French press 65-70%. Therefore, the grind size for cold drip coffee should be finer than pour-over coffee, around 83-85% passing rate.

2. Water flow rate

Throughout the dripping process, new cold water continuously passes through the coffee bed, then filters to form new coffee liquid. Compared to static cold brew, cold drip is a dynamic brewing method that extracts and filters simultaneously. So to prevent extraction interruption, we must ensure water droplets contact the coffee bed at a steady rate, thus achieving a cup of cold drip coffee with both concentration and taste.

Thus, controlling the water dripping speed is a crucial part of making cold drip coffee. If the water flow is too fast, extraction may be insufficient, resulting in weak coffee with no aroma; on the contrary, if the flow is too slow, the coffee may ferment, producing unpleasant sourness or off-flavors.

According to Front Street's experimental results, when using light-roast coffee 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 asFront Street Red Cherry, Front Street Little Tomato; when using medium-roast coffee beans to make cold drip,for exampleFront Street Sidra, Front Street Strawberry Candy, Front Street recommends controlling the flow rate to a slower state of 5 drops per 10 seconds, which will give the final coffee a rounder body and fermented feel.

3. Extraction ratio

The ratio for cold drip not only affects production time but, more importantly, determines the coffee's concentration and extraction yield. Considering that the coffee will ultimately be served with ice to maintain a low temperature, Front Street typically uses a 1:10 ratio for cold drip. For those who prefer a lighter taste, Front Street suggests using 1:12 to 1:14, making the resulting iced coffee more suitable for drinking directly.

4. Maturation time

I believe many people know that even cold drip extracted under the same conditions will taste very different depending on the number of days it is stored.

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

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

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

But since we know the production efficiency of cold drip is low, most of the time we don't just make one cup—we make as much as the equipment can hold. For example, the equipment used at Front Street stores can hold up to about 650ml of coffee liquid in the lower pot, so each batch makes three cups' worth, using 60g of grounds to drip 600g of coffee liquid, with the valve at 7 drops per 10 seconds, taking about 7 hours for dripping. Finally, the coffee liquid is refrigerated overnight and ready to sell the next day.

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

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