Price and performance comparison of Commercial Coffee Machine

First of all, let's recognize a problem: the way coffee is made by hand and French pressure. These methods all need to have a soaking process, which can also be understood as stewing. The role of stewing is to make the coffee powder fully contact with hot water before extraction, soak and expand. At this time, there is no real extraction of coffee. When we start to pour water again, the pressure begins to press down, and the pressure begins to press down, it is the separation of coffee liquid and coffee grounds. This is the real extraction stage.(Dissenting opinions are permitted, but are easily understood here by contrast). Viagra often says that making coffee is a one-way street, and making most coffee is the same truth. So it's easy to understand whether or not to pre-soak when making Espresso. At the beginning of the time with a small pressure (some machines start with tap water pressure, water tank machine has no pressure) to soak the coffee powder in the powder bowl, so that the coffee powder surface expands, so that the larger pressure (usually 9bar) When the water comes, the coffee powder surface is already fully prepared. Simply put, there are two advantages of pre-soaking: 1. The surface of coffee powder is fully absorbed, and there is no extraction. When 9bar water is extracted, the probability that all coffee powder particles can fully release aromatic substances is quite high. 2. The surface of coffee powder absorbs water and expands, which increases the contact area with the coffee machine water separation net, and is more compact, reducing the probability of extraction failure caused by uneven distribution of powder. Of course Viagra doesn't say it's bad to have no pre-brew coffee machine, because a coffee machine without pre-brew can make good coffee.

Here are a few pre-steeping methods for general awareness coffee machines:

1. Old drawbar coffee maker

Prepreg has existed since espresso was born, not something new invented in modern times. For the earliest drawbar machines, the pre-preg function was inherent. When making coffee, pull down the pull rod (lever), lift the piston, hot water into the cavity and filter bowl, hot water and coffee cake contact and start pre-soaking, at this time keep the pull rod not loose, until the desired pre-soaking time is completed, then release the pull rod, the piston under the action of the spring began to press down, to achieve coffee extraction. In this way, the pressure of the pre-soaked water is the pressure given in the boiler, and the extraction pressure comes from the pressure of the pull rod spring, which should be about 9bar at the highest.

Incidentally, the draw-rod machine does not require pressure relief because the spring pressure is already very low when the piston reaches the bottom of the cavity.

2.E61 brewing head

When the motor-driven pump works instead of the spring-and-piston, the barista can save a little time and effort. In order to achieve pre-impregnation in a new way, the brewing head of E61 was invented (of course, in addition to pre-impregnation, E61 also has the function of heating the brewing head by using the thermosiphon effect). The E61 brewer head has a cavity plus piston and spring system. This mechanical system allows the pressure of hot water in the filter bowl to build up slowly, thus achieving the effect of pre-soaking. FAEMA E61 This machine Viagra is still in use some time ago, the coffee production is really good, and the mechanical small pull rod brings the feel is very cool. The electronic pump is controlled by a small pull rod. The design is very clever. If the pull rod is not pulled to the end, it will always soak or even extract coffee at a very low pressure. There is a chance that everyone can play.

The E61 system has no solenoid relief valve, and the pressure in the bowl is manually released by moving a small handle.

3. Coffee machine

In the 60's, when automatic control technology was still expensive, the E61 brewing head was a smart solution. In today's microelectronics technology has become very popular, the implementation of prepreg is a very simple matter, the cost is much lower than the E61 solution. Electrically controlled version of the machine, prepreg generally has two working principles:

a) After pressing the make button, the water pump starts to run until the coffee is made, and the pressure relief valve is first opened (at this time, the pressure of hot water entering the filter bowl cannot be established), and it is closed after the pre-soaking is completed, and then the pressure relief valve is opened until the coffee is made.

b) After pressing the make button, the pressure release valve is always closed until the coffee is made and then the pressure release valve is opened, and the water pump runs briefly (at this time, the amount of hot water entering the filter bowl is small and the pressure is low), pauses for a while until the pre-soaking is completed, and then starts running again until the coffee is made.

4. Manual version coffee machine

What about the manual version of the prepreg? The manual "on-off-pause-on" approach is not advocated by experts. In fact, the pressure of the pump is not built up instantaneously. In addition, the water pipe entering the brewing head is very thin (or there is a very thin section) and has a limited flow effect. Therefore, the water pressure in the filter bowl is gradually built up. There is no need for manual pre-soaking.

In fact, no matter what kind of pre-soaking, the hot water only contacts the thinnest layer of coffee powder on the surface of the coffee cake pressed tightly in the filter bowl, not the whole coffee cake.