Front Street found that many friends are troubled by the problem of Moka pot coffee often being over-extracted. Because Front Street often shares tweets about Moka pots, some friends leave comments in the comment area with questions like: "How to avoid over-extracting coffee with a Moka pot" or "Why is the extracted coffee too bitter?" and other questions.
Moka pots, like espresso machines, use pressurized extraction. The advantage of pressurized extraction is that the extraction efficiency is very high, and the coffee can be extracted in a short time. However, due to the high efficiency, the coffee will be more likely to be over-extracted. Over-extracted coffee will have obvious burnt bitterness or many other flavors. Even if you add sugar and milk, the coffee will still taste unpleasant.
1. Channel effect
For pressurized extraction, one of the reasons why over-extraction frequently occurs in coffee is the "channel effect". What is the channel effect? This means that the hot water will be concentrated in a certain place for extraction, which will cause the coffee powder in this place to be over-extracted and the coffee powder in other places to be under-extracted. The coffee will taste bitter and sour, with a very poor balance.
The reason why the channel effect occurs is because water is inert and will preferentially flow to places where it is easy to flow. In order to dissolve a large amount of flavor substances in coffee powder in a short period of time, pressurized extraction of coffee powder generally uses very fine grinding, so that the powder cake has enough resistance to allow pressure to build up.
But if the coffee powder in a certain place is relatively small and the density is not as high as in other places, then hot water will be concentrated in this place and cause a channel effect. Therefore, if we want to improve the over-extraction problem of Moka pot coffee, we must first prevent the occurrence of channel effects. So, what factors lead to the channel effect?
① Uneven powder distribution: Just like espresso coffee, uneven powder distribution will cause channel effects. If the coffee powder that falls into the powder bowl is unevenly distributed and is filled without adjustment, the density of the powder cake will be different and the channel effect will occur.
Situations like this are easy to solve! After we put the powder into the powder bowl, we can pay appropriate attention to see if the amount of coffee powder in each place is similar. If so, we can perform filling and extraction.
And if not, we need to use our fingers to stir the coffee powder to make the coffee powder evenly distributed. Then tap the powder bowl gently to make the connection between the coffee powders closer, and finally fill and extract.
By adjusting the coffee powder in this way, we can make the density of the powder cake consistent and make the channel effect more difficult to produce.
②③, the fire is too small, use cold water: the initial water temperature and the size of the fire will have an impact on the extraction of coffee from the Moka pot. They mainly affect the length of time from the time when the Moka pot is heated to the time when the coffee liquid comes out. The longer the heating time, the easier it is to produce channeling during the extraction process.
As we all know, the reason why the Moka pot needs to be heated is to generate enough water vapor for pressure to push the hot water to extract the coffee powder. During the heating process, water vapor is continuously generated, and the steam in the water in the sink will flow upward and moisten the coffee powder at the bottom of the powder cake.
The density of the place that has been wetted by steam in advance will be reduced, and when it comes to extraction, this part will pass easier than the coffee powder in other places. If the heating time is longer, the powder cake will be moistened more, its density will be lower, and it will pass better.
The Moka pot is a pressurized extraction method that can best highlight the body and rich taste of coffee. If it is made with lightly roasted coffee beans, the texture of the lightly roasted beans is harder and a finer grinding degree is usually required to improve the extraction rate. However, fine grinding under high temperature and pressure not only easily makes the coffee sour and irritating, but also blocks the circulation of hot water, making it difficult to release the coffee liquid.
If you want the Moka pot to be more stable, you should give priority to using Italian blended coffee beans with a deeper roasting degree as raw materials. You can buy Front Street, which is rich in fat and has its own butter and chocolate aroma. Front Street classic blend, and Front Street, which is mixed with nuts and sweet like sugar cane. Brazil Queen's Manor.
If you don’t want your coffee to be too strong, it’s best to use Front Street Strawberry Espresso or Front Street Blackberry SOE. This way the Moka Pot can create a fresh, high-sweet taste with low bitterness and slight acidity. At the same time, because they are both processed with honey, the coffee has a rich aroma of berries and flowers.
Therefore, if conditions permit, Front Street recommends that you use medium to high heat to cook Moka pot coffee before discharging the liquid, and then the higher the initial water temperature, the better. In this way, the occurrence of channel effects can be greatly reduced, and there is a higher probability of making delicious coffee.
2. The firepower is too great after the liquid is discharged
It is worth noting that after the liquid is discharged, the best way to cook the Moka pot is to reduce the heat to low or even turn it off, and use the residual heat to generate steam to extract the Moka pot coffee.
Because if you continue to use the current firepower to extract coffee after the liquid is discharged, it will be over-pressurized due to excessive steam, allowing the hot water to quickly pass through the powder cake in a short period of time, and the extraction time will be greatly shortened. In addition to under-extraction, continuous cooking over high heat can also cause a channel effect, making coffee both bitter and sour.
3. Too fine grinding and too much water
Moka pots will come with an instruction manual, which details the usage method and official recommended parameters. For example, for 2 people, pour xx powder and 120ml of water for cooking, and for 4 people, use xx powder and 180ml. Many friends will follow the parameters in the instruction manual when they first get in touch.
There is nothing wrong with this, but if your grinding degree is relatively fine, which is close to flour-like particles like the grinding of an espresso machine, then you need to pay attention to the amount of water used.
Because finely ground coffee powder will precipitate flavor substances more easily, and more water will increase the dissolved flavor substances. If we use flour-like particles for grinding and use a lot of water, it will be easy to extract a cup of moka pot coffee that is burnt, bitter, and rich in flavor.
The coffee powder used by many friends is pre-ground, and the grinding degree cannot be adjusted freely. Therefore, in this case, we need to control the coffee extraction rate by adjusting the amount of water and the firepower after the liquid is discharged. However, the latter is relatively difficult to adjust, so Front Street recommends adjusting by reducing the amount of water.
So, the above are the three main reasons that Front Street can think of that lead to over-extraction of Moka pot coffee. If you have any other findings, please feel free to add them in the comment area~
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
