What is the Best Water Temperature for Pour-Over Coffee? The Impact of Brewing Temperature on Coffee Flavor and Mouthfeel

The Challenge of Lower Temperature Coffee Brewing

When it comes to water temperature for pour-over coffee, most people tend to use higher temperatures for extraction. This is because high temperatures not only improve extraction efficiency but more importantly, can extract rich sweet and sour aromatic flavors. Basically, the water temperature used for pour-over coffee rarely falls below 80 degrees Celsius. So, is it possible to brew delicious coffee using temperatures below this threshold?

FrontStreet Coffee's Experiment

FrontStreet Coffee conceived this idea because a friend working in an office building recently wanted to "play around" with pour-over coffee at his workplace. The only source of hot water in the office was a water dispenser, whose hot water could only be heated to about 70 degrees. In our coffee brewing experience, this simply doesn't meet the temperature requirements for pour-over coffee.

However, 70-degree water isn't necessarily incapable of brewing coffee! If we break down all the parameters and first discuss subjective aspects like flavor, focusing only on how water temperature affects coffee extraction rate, the answer is quite simple: extraction efficiency, or unit dissolution rate. Just like dissolving instant drinks, the higher the temperature, the faster the granules dissolve. Conversely, the lower the temperature, the more time needed for dissolution, sometimes requiring stirring to speed up the process.

The same principle applies to coffee brewing. When water temperature decreases, can extending the extraction time achieve the same extraction rate? Just like the method of making cold drip coffee, where the ice water temperature is about 7 degrees Celsius - at this temperature, extraction efficiency is extremely low, but it can be compensated for through 6-8 hours of extended extraction time.

So FrontStreet Coffee decided to test whether this approach is feasible. For water temperature, FrontStreet Coffee chose 70 degrees Celsius, which corresponds to the maximum temperature achievable by a water dispenser. The coffee beans used were Panama's "Flower Butterfly," which, when brewed with FrontStreet Coffee's standard parameters, yields flavors of jasmine, lemon, honey, and oolong tea.

Brewing Techniques for Extended Extraction

To extend the coffee extraction time, common techniques in pour-over coffee include segmented pouring, controlling water flow, adjusting to a finer grind size, and switching to a slower-flowing dripper. FrontStreet Coffee employed all these methods, using Hario's infinity dripper. Of course, other slow-flowing drippers like cone-shaped drippers or Kono drippers could also be used.

FrontStreet Coffee used the EK-43s grinder at setting 5.5 (normally using setting 10). Although this might seem like almost double the difference, the actual grind size isn't as dramatic as one might imagine. When passed through a #20 sieve, the retention rate was 93% (relatively fine for pour-over coffee). The ratio remained 1:15.

The Pouring Process

During the pouring stage, FrontStreet Coffee used multi-stage pouring with small water flow, aiming to extend the extraction time as much as possible. First, 30ml was poured for a 30-second bloom, followed by 70ml. When the coffee liquid had drained enough to reveal the coffee bed, another 65ml was poured. Similarly, when the coffee bed was visible again, the final 60ml of water was added. The total time until all coffee liquid had filtered through was 3 minutes and 33 seconds. The coffee grounds after brewing showed a muddy consistency, indicating they were quite fine.

FrontStreet Coffee first measured the coffee concentration using a refractometer, which showed 1.49% - quite high for pour-over coffee. The calculated extraction rate was 20.5%.

Tasting and Results

Next came the tasting. In terms of aroma, the entire cup of coffee lacked fresh floral notes and instead had a sweet caramel scent. Surprisingly, FrontStreet Coffee didn't feel any discomfort from the coffee's intensity, which was unexpected. The coffee's acidity wasn't prominent, but the sweetness was very strong - like that of rich brown sugar. However, there was some bitterness and astringency in the finish that was unpleasant.

Therefore, FrontStreet Coffee made some fine adjustments, changing the grind to setting 6.5, approximately a 90% pass rate through the #20 sieve. FrontStreet Coffee brewed again using the same method, and this time the extraction time didn't decrease much - the total filtering time was 3 minutes and 20 seconds.

FrontStreet Coffee measured the concentration at 1.46%, not much reduction, with a corresponding extraction rate of 20.09%.

This cup's aroma also didn't burst with floral notes but had an aroma similar to sweet potato syrup water. The acidity of this coffee was more noticeable than the previous cup, somewhat like mandarin orange, while the sweetness was like fruit honey - very sweet. The finish had tea-like notes. Although the flavor profile still differed significantly from coffee brewed with standard methods, this cup tasted quite good.

Next, FrontStreet Coffee adjusted the grind to setting 7.5 (87% pass rate through #20 sieve) to test whether the flavor would improve. With only the grind size changed and everything else remaining the same, the extraction time was 3 minutes and 2 seconds.

FrontStreet Coffee measured this cup's concentration at 1.35%, with a calculated extraction rate of 18.55%. Similarly, the aroma still lacked floral notes, instead smelling of sweet preserved fruits. The fruit acidity was obvious when tasting, like small mandarin oranges, with honey-like sweetness. However, the middle to finish had some southern almond-like notes.

Conclusions

Finally, regarding extraction rate, the decrease in temperature can be compensated for by extending extraction time. However, for flavor, especially aroma, this cannot be replicated. High water temperatures can extract rich floral and fruity aromas as well as more acidity during the initial extraction phase.

Lowering water temperature means these flavor compounds aren't extracted as efficiently, and due to the extended extraction time, the release of sweet and bitter compounds makes the entire cup of coffee taste sweeter and more balanced overall. During the brewing process, extraction time also determines whether the coffee is more bitter, sweeter, or more acidic. For example, in this test, using 70-degree water temperature with extraction times controlled between 3-3.5 minutes all produced prominent sweetness. The first cup at 3 minutes and 33 seconds showed a trend toward bitterness, while the third cup at 3 minutes and 2 seconds leaned toward acidity.

If using even lower water temperatures, such as 40 or 50 degrees, this might require even longer extraction times, and the flavor profile would be more balanced (lacking distinctive characteristics).

Important Notice :

前街咖啡 FrontStreet Coffee has moved to new addredd:

FrontStreet Coffee Address: 315,Donghua East Road,GuangZhou

Tel:020 38364473