我们需要烧水20分钟左右，因为是小酒精灯。水由于加热变为水蒸气，水蒸气

We need to boil water for about 20 minutes, because it is a small alcohol lamp. The water turns into water vapor due to heating, and the water vapor gradually soaks the coffee powder through the perforated lid. The pressure of water vapor in the airtight container is getting higher and higher, which will push the water from the tube to the upper cup. Converting water to water vapor in the same volume, the water vapor in this volume will generate huge pressure), which will last for a while. We remove the heat source, and the water in the upper cup (that is, the prepared coffee) will also fall back into the round bottom beaker through the tube. This is because the heat source is removed and the water is no longer boiled, so no steam is produced, and the steam is reduced. Cooling means that the internal pressure of the water beaker decreases. When the water vapor pressure is no longer greater than the mass of water, the water will fall (note: the coffee in the upper cup did not fall down immediately when the heat source was just removed, because of the residual heat in the beaker reason.). And this method of "making coffee" is very high-end, purer and more expensive.

We need to boil water for about 20 minutes because it's a small alcohol lamp. As the water heats up, it becomes water vapor, which gradually soaks the coffee powder through the perforated lid. Water vapor creates increasing pressure in an airtight container, pushing water from the tube into the upper cup (for example, mr. Class: we have a volume of water and a volume of air, a volume of air with a mass less than a volume of water, and if water is converted into water vapor at the same volume, there will be great pressure on water vapor in this volume), which will last for some time. We remove the heat source, the water in the upper cup (i.e. made coffee) will also pass through the tube back into the round bottom be cup, because the heat source is removed water is no longer boiled so not to produce water vapor, water vapor cooling for the water behemoth internal pressure is reduced, when the water vapor pressure is no longer greater than the quality of the water, the water will fall (note: just remove the heat source when the coffee in the cup does not immediately fall down, because the heat in the cup. )。 And this "coffee-making" method is very high-end, purer and more expensive.

We need to boil water for about 20 minutes because it's a small alcohol lamp. The water changes into steam due to heating, and the water vapor gradually soaks the coffee powder through the perforated cover. The pressure of water vapor in the closed container is increasing, which will push the water from the pipe to the upper cup (for example, we have integral water and a volume of air, and the mass of one volume of air is less than that of integral water. If water is converted into steam under the same volume, the water vapor in this volume will generate huge pressure), which will last for a period of time. When we remove the heat source, the water in the upper cup (that is, the prepared coffee) will also fall back into the round bottom beaker through the pipe. This is because the heat source is removed and the water is no longer boiled, so no steam is generated. When the water vapor pressure is no longer greater than the mass of water, the water will fall down (Note: when the heat source is removed, the coffee in the upper cup will drop It didn't fall immediately because of the waste heat in the beaker. And this method of "making coffee" is very high-end, purer and more expensive.<br>