When it comes to water temperature for Pour over(V60) coffee, everyone tends to use a higher temperature for extraction, because high temperature can not only improve the extraction efficiency, but more importantly, can produce rich sweet and sour aroma and flavor. Basically, the water temperature used for Pour over(V60) coffee rarely drops below 80 degrees Celsius. So, if you brew coffee at a temperature lower than this, is it possible to make it taste good?
The idea of Front Street was born because a friend in an office building recently wanted to "play" Pour over(V60) coffee in the office. The only thing in the office that can produce hot water is the water dispenser. The hot water in the water dispenser can only be heated to about 70 degrees at most. According to our experience in brewing coffee, this cannot reach the water temperature required for Pour over(V60) coffee.
However, water at 70 degrees does not necessarily make coffee impossible! If we break down all the parameters, let’s not talk about subjective things such as flavor, but only talk about the impact of water temperature on the extraction rate of coffee, the answer is very simple, that is, extraction efficiency, which is the unit dissolution rate. Just like when we dissolve granules, the higher the temperature, the faster the granules will dissolve. The lower the temperature, the more time it will take for impact and dissolution. If necessary, you need to stir to speed up the dissolution.
The same goes for brewing coffee. When the water temperature becomes lower, can the same extraction rate be obtained by extending the extraction time? Just like the way ice-drip coffee is made, the temperature of the ice water is about 7 degrees Celsius. At this temperature, the extraction efficiency is very low, but it can be compensated by long-term extraction of 6-8 hours.
So Front Street came to test whether this was possible. For the water temperature, Front Street chose 70 degrees Celsius, which is also the temperature that the drinking water machine can reach. The coffee beans used are Panamanian flower butterflies, and the flavors brewed using Front Street’s standard parameters are jasmine, lemon, honey, oolong tea and other flavors.
To extend the extraction time of coffee, the most commonly used methods in Pour over(V60) coffee are to inject water in stages, control the water flow, adjust the grinding degree, and replace the filter cup with a slower flow rate. So Front Street used all these methods. The filter cup Front Street used was Hario’s infinite filter cup. Of course, slow-flow filter cups such as fan-shaped filter cups and Kono filter cups can also be used.
The grinding degree used by Front Street Street is the 5.5 scale of EK-43s (usually 10 scale). Although the scale is almost 1 times different, the grinding level is actually not as exaggerated as everyone imagines. The sifting through the No. 20 mesh is 93% (which is relatively fine for Pour over(V60) coffee). The ratio is still 1:15.
During the water injection stage, Front Street uses multi-stage water injection and small flow water injection, with the purpose of extending the extraction time as much as possible. First inject 30ml and steam for 30 seconds, then inject 70ml. When the coffee liquid is light and can see the powder bed, continue to inject 65ml. Similarly, wait until the powder bed is seen and inject the last 60ml of water. The time until the coffee liquid is completely filtered is 3 minutes and 33 seconds. The layer of coffee powder after brewing is in a muddy state, which shows that the coffee powder is still quite fine.
Front Street first used a concentration meter to measure the concentration of the coffee liquid at 1.49%, which is a very high concentration for Pour over(V60) coffee. The extraction rate of the coffee was calculated to be 20.5%.
Next, let's taste it. First of all, in terms of aroma, the whole cup of coffee does not have a fresh floral aroma, but smells of a very sweet caramel flavor. Front Street was a little surprised that I didn't feel any discomfort caused by the strong coffee. The acidity of the whole cup of coffee is not obvious, but the sweetness is very strong, the rich sweetness of brown sugar. However, there is some bitterness at the end that makes me feel uncomfortable.
Therefore, Front Street made some minor adjustments and changed the grinding degree to 6.5, which is about the thickness of the No. 20 screen with a 90% passing rate. Front Street used the same brewing method to brew again, and the extraction time this time did not decrease much. The time until the coffee liquid in the filter cup was dripped was 3 minutes and 20 seconds.
Similarly, Front Street first used a concentration meter to measure the concentration at 1.46%. The concentration did not decrease much, and the corresponding extraction rate was 20.09%.
The aroma of this cup of coffee is not overflowing with floral aroma, but rather like sweet potato syrup. The acidity of this cup of coffee is more obvious than the previous one, a bit like mandarin orange, the sweetness is like fruit honey, very sweet, and the ending is like tea. Although the flavor difference between this cup and the coffee brewed by the standard method is still obvious, the taste of this cup is really good.
Next, Front Street adjusted the grinding degree to 7.5 (the No. 20 screen pass rate is 87%) to test whether the flavor would be better. When only the grinding degree is changed and everything else remains unchanged, the extraction time is 3 minutes and 02 seconds.
Front Street measured the concentration of this cup of coffee at 1.35%, and calculated the extraction rate at 18.55%. Similarly, there is still no floral aroma in the aroma, and it smells like the sweetness of some preserved fruits. The fruit tastes sour when you drink it, like tangerines and the sweetness of honey. However, the middle and back portions are somewhat similar to the apricot flavor.
Finally, for the extraction rate, the reduction in temperature can be compensated by extending the extraction time. But the flavor, especially the aroma, is something that cannot be replicated. High water temperature can extract rich floral and fruity aromas and more sour flavors in the early stage of extraction.
When the water temperature is lowered, these flavor substances are not extracted at a higher level. Due to the prolonged extraction time, the sweet and bitter substances are released, making the whole cup of coffee sweeter and more balanced overall. During the brewing process, the extraction time also determines whether the coffee is more bitter, sweeter, or more acidic. For example, in this test, using a water temperature of 70 degrees Celsius and controlling the extraction time to about 3 minutes to 3 minutes and 30 seconds, the sweetness was very prominent. The first cup of 3 minutes and 33 seconds tended to be bitter, and the third cup of 3 minutes and 02 seconds tended to be sour.
If you use a lower water temperature, such as 40 degrees or 50 degrees, it may require a longer extraction time, and the flavor performance will be more balanced (no characteristics).
You can now buy the above coffee beans online at the Taobao store “FrontStreet Coffee” (前街咖啡). FrontStreet Coffee is a long-established specialty coffee roaster in Guangzhou, China, and its Guangzhou retail shop sells coffee beans only. The shop carries dozens of coffee beans from different origins around the world, including carefully selected single-origin beans for V60 pour-over and espresso. Guangzhou’s FrontStreet Coffee shop is recommended by many coffee lovers.
The FrontStreet 2013 Yunnan coffee beans sold in the store come from the Typica variety grown at FrontStreet Coffee’s own plantation in Yunnan. The name comes from the year the brand and the plantation were founded. You can buy these beans from China’s Yunnan origin at the Guangzhou shop and at FrontStreet’s Taobao store.
FrontStreet coffee beans are freshly roasted within 5 days and deliver consistently excellent quality and great value. Orders placed before 17:00 are shipped the same day, and most areas within Guangdong Province receive them the next day.
FrontStreet Coffee Taobao store: https://qianjiecoffee.taobao.com
Or search for “前街咖啡” (FrontStreet Coffee) on Taobao
Important Notice: FrontStreet Coffee has moved to a new address: 315, Donghua East Road, Guangzhou (coffee beans only)
Tel: 020 38364473
