What is WDT? How to use needle powder dispenser? Is it necessary to buy a needle type powder dispenser

Cloth powder is a required course for every barista. There are thousands of details to be paid attention to in a good Espresso, but the action of making a bad cup of coffee is only in an instant.

Whenever a rainy day comes, the Italian concentration of Qianjie is prone to channel effect in relatively humid air.

The extraction process of Espresso is that hot water permeates the coffee pressed powder under high pressure to release the soluble matter. When the density of pressed powder is inconsistent and the water passes through the obstacles of different "intensity", it chooses to "drill" into the gap with the least resistance.

The front street can see water jetting down through the bottomless handle, which is the most common phenomenon of the channel effect. The channel effect leads to the excessive extraction of the position where the water flows, while the position where the water is avoided is not enough, so the Espresso often has obvious bitterness and astringency.

When extracting espresso, a relatively fine degree of grinding is needed, and the friction between the fine powder in the process of producing powder produces static electricity, which makes the powder agglomerate. Even if the pressed powder is finally paved and compacted, the flow of water will "dodge" the tight caking position during extraction and pass through a looser place.

In order to solve the trouble caused by static electricity in the production of concentration, a Weiss Distribution Technique method (WDT for short) and needle cloth powder dispenser have appeared.

In 2005, when John Weiss John Weiss used a home bean grinder, the channel produced too much powder and caked, so he invented WDT. Use fine needles or similar tools to stir the coffee powder in the powder bowl to break up the lump powder and make the density distribution of the powder layer more uniform.

In the early days, many commercial bean grinders were usually equipped with anti-static power grids that broke large lumps, and the coffee powder that fell into the powder bowl was relatively uniform, so the emergence of WDT was not widely recognized by baristas.

With the growing atmosphere of boutique coffee, baristas continue to explore the various techniques of Espresso. By measuring and analyzing the pressure and flow rate in pressed powder, a number of techniques have been summarized to make the extraction more stable, including WDT. In particular, the contestants in the competition use it most frequently.

WDT tools usually use fine metal needles about 1mm in diameter, such as the one on Qianjie hand, which is a simple and compact design.

With the larger the size of the cloth powder, the more fine needles, and the appearance is as grandiose as a porcupine.

In operation, it is only necessary to connect the handle with the powder ring to the coffee powder and break up the coffee powder layer through the needle structure, so as to eliminate the caking and uneven problems caused by static electricity, and make the coffee powder surface without excessive undulation. Because the contact area between needle and powder is very small, this type of powder distributor is almost free of powder.

Qianjie compared the extraction process before and after the use of needle powder distributor. It is noted that the pressed powder extraction using a needle distributor is stable, and the concentrated column is stably located in the center of the powder bowl throughout the process.

The unused pressed powder concentrated and beat in the middle and later part of the extraction, and the color of the liquid was also somewhat uneven at the moment of offset from the central point.

Qianjie summed up during the operation that the needle cloth powder machine decomposes the coffee blocks and redistributes the powder bed from top to bottom, resulting in a steady improvement in the quality of the extracted Espresso. In addition, stirring should be vertical and gentle to avoid violent coffee powder spilling or uneven powder layer density.

In the daily bar production of coffee shops, speed and consistency are particularly important, so it is difficult to widely use WDT tools.

The addition of the WDT tool will increase the preparation time per cup of espresso, which goes against the efficiency of espresso.

At present, coffee circle cloth powder tools emerge one after another. I believe that a comprehensive powder distributor with WDT function will be launched in the near future, which can eliminate the annoyance caused by the channel effect for every barista.

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