What is the Three Warm Hand Brew Method? Introduction to Variable Temperature Brewing Principles and Parameter Characteristics

In the world of coffee brewing, besides the beans themselves, there are three main variables that affect the extraction stage: grind size, water temperature, and coffee-to-water ratio. These are also the most commonly used parameters for quickly adjusting a pour-over coffee.

Following the principle of playing it safe, compared to the other two factors, water temperature is generally our "year-round constant" value—either using a lower 88°C, adopting a higher 93°C, or taking the middle value of 90°C, mainly focusing on avoiding mistakes.

However, in the eyes of some brewing champions, water temperature can become their key variable for adjusting coffee flavor. Using two or three different water temperatures for segmented brewing to achieve an ideal extraction model, this technique is also known as "variable temperature brewing." For example, the Three-Temperature Pour-Over Method, invented and used by 2016 World Barista Championship (WBC) winner Tse-Lin Wu, is still favored by many enthusiasts today, and FrontStreet Coffee plans to recreate it.

Why Use Multiple Water Temperatures to Brew Coffee?

In previous articles, FrontStreet Coffee has always emphasized that higher water temperatures more easily accelerate the extraction efficiency of flavor compounds in coffee, causing the sour, sweet, and bitter components from various stages to be released more quickly; conversely, lower water temperatures make soluble substances more difficult to diffuse into water, requiring longer brewing time to obtain flavor. The water temperature we often refer to is actually the value measured by the thermometer before formal pouring, known as the initial kettle temperature, which gradually decreases step by step with room temperature throughout the process.

In reality, brewing coffee can be seen as a process of controlling flavor molecules such as sour, sweet, bitter, and astringent. According to the coffee flavor release fluctuation chart, acidity and sweetness are more concentrated in dissolving during the early to middle stages, while body and bitter substances are released more in the later stage.

If a relatively high initial water temperature is used in the early stage, the coffee bed will maintain a high-temperature environment, and the large release of acidic and sweet substances will give the coffee higher flavor complexity. Of course, some of the thick bitter substances will also come out earlier accordingly. Therefore, to achieve a balanced taste of sour, sweet, bitter, and pleasant aftertaste, it's necessary to suppress the movement of bitter and astringent components in the final stage by lowering the water temperature, which means preventing over-extraction.

Specific Parameters of the Three-Temperature Pour-Over Method

As the saying goes, "Good tools are prerequisite to the successful execution of a job." To play with variable temperature brewing, you first need to equip yourself with containers that can provide several different temperatures. Tse-Lin Wu's Three-Temperature Pour-Over Method, as the name suggests, involves 3 temperature values: 94°C, 90°C, and 80°C.

In terms of coffee powder and water distribution, he uses 16 grams of powder as the standard commonly used in his shop, with a coffee-to-water ratio of 1:15, divided into four pouring segments of 1:2:2:1, meaning a total of 240 grams of hot water needs to be poured (40g, 80g, 80g, 40g).

Here, FrontStreet Coffee plans to use 2 pour-over kettles + 1 room temperature water kettle to achieve this. First, pour the boiled water into two pour-over kettles respectively. One kettle's lid is opened to cool to 94°C for the first bloom + second segment. The second kettle of water is covered with a lid and fitted with a thermometer to cool naturally. By the time of the third pour, it will have cooled to about 90°C. Immediately after, add a small amount of room temperature water (about 15-50ml) to the first pour-over kettle to bring the temperature to 80-85°C, then immediately proceed with the final pour.

In terms of grind size, Tse-Lin Wu did not give an exact figure, but asked everyone to judge based on their total brewing time. FrontStreet Coffee believes that if the dripping time is less than 2 minutes, you can grind the powder finer. If your coffee takes more than 2.5 minutes, you can consider grinding it coarser.

FrontStreet Coffee is using a honey-processed Geisha from the New Oriental region of Guatemala, a medium-light roast coffee that tends to express sweet aromas like toffee, sweet orange, and cocoa biscuits. Therefore, we will use the fine sugar grinding commonly used in our daily store production, which is the coarseness with 80% pass-through rate of a #20 sieve (EK43s grinder setting 10). As for the filtering equipment, FrontStreet Coffee plans to use the recently acquired Hero variable-speed flat-bottom cake filter cup, which can provide temporary immersion function in the final stage.

Let's Start Brewing Without Delay

For the first bloom, pour 40g of 94°C hot water in a circular motion and bloom for 30 seconds. (Before pouring, first confirm that the cake filter cup setting is in drip mode for even water flow.)

After the bloom ends, continue using the same high-temperature water with a large flow, slow circular motion to pour the second segment of 80g, raising the coffee bed to 2/3 of the filter cup's height.

When the coffee liquid in the filter cup is almost completely dripped through, you can pick up the other kettle with pre-prepared 90°C hot water to start pouring the third segment. Similarly, use a large flow, slow circular motion to pour 80g. After pouring, the liquid level will just reach the height of the powder layer formed by the previous second segment.

While the coffee liquid in the filter cup is still extracting, we add a small amount of room temperature water to the high-temperature kettle, bringing the thermometer reading to 80°C, preparing to start the final pour.

Wait for all the coffee liquid to flow into the lower kettle, turn the filter cup knob to immersion mode, pour the remaining 40g of water onto the powder layer, and immerse for 20 seconds. Finally, open the valve to let it all flow into the lower kettle. The total coffee dripping time is approximately 2 minutes and 18 seconds.

Tasting Notes

Finally, FrontStreet Coffee tasted very prominent aftertaste from this pot of New Oriental Geisha brewed using the Three-Temperature Method. The entry shows solid and uplifting citrus acidity, with some chocolate aroma and the sweetness of dried cranberries, accompanied by a mouth-watering sensation—it's a very comfortable coffee to drink.

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FrontStreet Coffee

No. 10, Bao'an Qianjie, Yandun Road, Dongshankou, Yuexiu District, Guangzhou, Guangdong Province

Important Notice :

前街咖啡 FrontStreet Coffee has moved to new addredd:

FrontStreet Coffee Address: 315,Donghua East Road,GuangZhou

Tel:020 38364473