Types of coffee machine-advantages and disadvantages, structure and function differences between American coffee machine and Italian coffee machine

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There are many utensils for making coffee, including French filter kettle, wind kettle, hand brewing pot and all kinds of coffee machines.

This article mainly introduces the mechanical coffee machine.

Mechanical coffee machines are mainly divided into two categories, one is American coffee machine, the other is Italian coffee machine.

The American coffee maker is relatively cheap because of its simple function. Most of the coffee pots sent by cards on the market, or coffee machines with a full price of about one thousand yuan from store promotions, are American-style coffee machines. The American coffee machine flushes out the original liquid of the coffee in the way of filtering, so it will be lighter in taste.

The structure of the Italian coffee machine is more complex, and its function is slightly better. It can make milk foam and even multiple types of coffee such as cappuccino.

The price of Italian coffee machine is often tens of thousands of yuan or even to the coffee chain gold mine on the market, the professional equipment of 85C will cost hundreds of thousands of yuan. In the general small family is the main consideration of less purchase, Italian coffee machine is the way of high-temperature and high-pressure extraction to flush out the original coffee liquid, the taste is relatively strong.

American coffee machine

Advantages, easy to operate, large supply.

Disadvantages: long extraction time, easy excessive extraction, high caffeine, easy oxidation after cooking and storage for a long time.

Cooking method: put in filter paper-put in ground coffee powder-set the amount of water required-drip

The fineness of the American coffee machine powder needs to be adjusted, and the coffee dripping speed is slightly slower than the hot water flowing down the machine.

Italian coffee maker

Advantages: stable, steam supply, fast and continuous supply of coffee, low caffeine, coffee oil can be boiled.

Disadvantages, large volume, need special bean grinder, need professional soft water equipment, need professional training.

Cooking method: remove the handle of the filter cup-drop the powder from the bean grinder to the filter cup-fill the powder in the filter cup-hot water and pressure to cook

# there are many kinds of Italian coffee machines, manual, semi-automatic and fully automatic

There are several forms of boiler

1. Single boiler (manual piston machine, small household machine)

two。 Double boilers or multiple boilers (steam hot water is separated from coffee hot water boiler)

3. Heat exchange boiler (coffee boiler interspersed with steam hot water boiler)

Since Luigi Bezzera launched the first commercial coffee machine with steam pressure in 1901, whether it is the Pavoni Gaggia or other machines that use steam or pistons as pressure, there has been only one boiler: the bottom of the boiler is the hot water for brewing coffee, and the top provides steam, but in order to produce steam, the whole boiler must be heated to boiling, causing hot water near the boiling point to burn the coffee powder and lose the aromatic oil hidden deep in the coffee powder. And extract the coffee that is doubly bitter.

Because the water for brewing coffee is heated in a large boiler, the water will not be fresh if it is placed in the boiler for too long, and the temperature difference of hot water will increase due to the use of steam, because the different amount of steam also increases the temperature difference of hot water for brewing coffee.

In order to improve the temperature difference, in 1960, Ernesto Valente, in the world's first pump-powered FAEMA E61, changed the way the water used to brew coffee was heated, so that the water used to make coffee did not come into direct contact with the heat source, but used a method similar to water-separated heating.

In the middle of the boiler of FAEMA E61 (hereinafter referred to as the outer boiler) is a tube (hereinafter referred to as the inner pipe line), which uses a pump to introduce fresh cold water into the internal curved pipeline. When the pump pushes the fresh cold water through the tube, the cold water will become hot due to the hot water in the outer boiler, but there are tubes around it, so the fresh water will not come into contact with the hot water of the outer boiler, and the inner water pipe is curved in shape. the aim is to make the cold water have enough time to come into contact with the external boiler and become a hot water temperature just suitable for brewing coffee.

(see the picture below, which is a bit simple.)

┌─ vapor

│ ┌─ →

│ │

┌─┐ │ ^ │ water level

Cold water ─┴ ┴─┴──┐┌──┴──┐

→ ─┬ ┬─┬─┐││┌─┬─┐│

└─┘ │ │└┘│ │ shower head

Pump │ └──┘ │

│ │

│ │

└─┘

Boiler boiler

Due to the circulation of hot water in the boiler, the temperature of each cup of coffee is very close, whether it is one cup an hour or a hundred cups at a time. In this way, it can not only reduce the temperature difference, but also take into account the freshness of the water, while the hot water in the outer boiler is only used to produce steam to make milk foam, not to brew coffee.

This is the principle of a single boiler heat exchanger. Today, more than 30 years later, the internal structure and principle of most Italian coffee machines are still very close to the FAEMA E61.

From the above explanation, we can infer that the larger the capacity of the external boiler, the lower the temperature difference in the hot water for brewing coffee, and the more it can reduce the temperature difference caused by the use of steam.

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