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With the launch of a new generation of pressurized moka pots, everyone's attention has turned back to this coffee device that has been around for 90 years. Moka pots have set off another wave, and many friends have asked Front Street Coffee to talk about how to choose between single-valve and dual-valve moka pots, while others want to know how to use a moka pot. So Front Street Coffee is here to explain the basics of moka pots.

Must the moka pot's filter basket be filled to the top?

When filling the moka pot's filter basket, it is recommended to fill it completely. This way, the coffee extraction will be better than if you only fill it halfway. If you only fill it halfway, the resistance of the water passing through the coffee will be reduced, so the extracted coffee will tend to taste weaker and won't be as rich when you drink it. So it's not that you must fill it completely, but rather that coffee made without filling it completely may not taste as good.

The principle is simple: the less coffee grounds used, the less resistance the hot water encounters, and the easier the coffee liquid enters the upper chamber. First, this shortens the extraction time, causing the coffee to taste sharply sour; second, because the hot water keeps washing through, it over-extracts the bottom layer of grounds, making the coffee unbearably bitter.

Front Street Coffee often mentions in articles about espresso extraction that water has inertia and will preferentially choose the "path" with less resistance to pass through, commonly known as the "channeling effect." So besides the change in resistance, using less coffee also leaves some space inside the filter basket. When the hot water moves upward, it will preferentially bypass the coffee bed and go straight to the upper chamber, and this portion of coffee liquid will most likely be under-extracted.

If you want to make a cup of moka pot coffee with less coffee grounds, Front Street Coffee suggests that when pouring the coffee grounds into the filter basket, first gently tap left and right to let the fluffy coffee grounds fall naturally and make the particles closely connect with one another. Then find a small spoon and use its back to gently "press" the coffee bed until the coffee bed is completely reduced to half its thickness. To avoid over-extraction caused by too long contact between the hot water and the thinned coffee bed, before loading the filter basket, first pour half the amount of high-temperature hot water into the lower chamber. This can effectively shorten the heating time. When the moka pot's liquid fills the bottom, immediately remove it from the heat source, then use the residual heat to release all the remaining coffee liquid.

After this adjustment, not only did splattering not occur, but there was also a small amount of foam layer, and the concentration was much higher. Front Street Coffee made this "half-batch moka pot coffee" into iced milk coffee. On the palate, there are obvious cocoa and cream flavors, and the mouthfeel is balanced and mellow.

So, is a single-valve moka pot better or a dual-valve one better?

According to different structures and functions, moka pots come in two types: single-valve and dual-valve. Single-valve means the extracted coffee liquid flows out directly from the small hole at the top. A dual-valve moka pot adds a pressure-accumulating valve on top of the hollow tube. During extraction, it blocks the small hole in the hollow tube where the coffee liquid comes out, and a certain steam pressure is required to push it upward and open it. Therefore, the dual-valve moka pot with greater steam pressure can extract richer coffee oils, and the flavor is also more intense. But the increase in pressure also makes it easy to over-extract the coffee, so the grind size and dose of the coffee grounds need to be adjusted.

Front Street Coffee believes that a single-valve moka pot has a higher margin for error, and the coffee it brews is less likely to be over-extracted. It is friendlier to beginners who are new to coffee. A dual-valve moka pot, however, requires greater outflow pressure and easily extracts oils, but the risk of over-extraction is also greater. If you are not careful, the coffee you make will be very bitter.

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