What is the principle of magic filter paper? What are the characteristics of non-woven coffee filter paper? What is non-weaving?

Recently, a friend brought a special filter paper to Qianjie evaluation. He said that this is a very magical non-bypass water filter paper, no matter what liquid is poured into the filter paper, it will not seep out of the filter paper when we do not start to extract coffee. Only after the coffee powder is poured in and the hot water comes into contact with the coffee powder to turn into coffee liquid will it begin to seep out.

This brings up the interest of Qianjie, so today let's test how magical this filter paper is.

Magical non-bypass filter paper? After the introduction on the packaging, Qianjie found that this is a non-woven filter paper, but it is very different from the conventional non-woven filter paper in terms of appearance and feel. As we all know, non-woven filter paper is made of special plastic. Because it does not need to be made by spinning, weaving and other processes, it also has a nickname for non-weaving. As the gap of the non-woven filter paper is larger than that of the conventional wood pulp filter paper, in addition to the coffee liquid, the coffee oil and fine powder can also pass through the filter paper to enhance the aroma and alcohol of the coffee. But as a result, it will feel rougher.

And this special non-woven filter paper will look closer to wood pulp filter paper, and its texture is not rough, but very smooth, with a little fluffy feeling. Details can be seen in the following picture, from left to right, are wood pulp filter paper, special non-woven filter paper and conventional non-woven filter paper.

So Qianjie began the test, put the filter paper into the filter cup, and then poured into the normal temperature water, hot water, and coffee liquid.

It was found that no liquid could seep out of the filter paper when poured into the normal temperature water. The water in the filter paper is like the oil in the non-stick pan, completely alienated. But then the front street uses hot water and coffee liquid, and when it is poured into the filter paper, the liquid seeps out of the filter paper. Although the rate of infiltration is very slow, it is not completely alienated like pouring into normal temperature water. Then Qianjie conducted an extraction test and began to brew coffee. Just after the coffee powder and hot water came into contact with the filter paper, the coffee liquid began to release immediately and flowed out at a relatively fast speed, which was completely different from the previous flow rate of pouring water.

After the brewing is over, we can see clearly from the filter paper that only the part of the filter paper that comes into contact with the coffee powder is wet by the coffee liquid. On the other hand, those parts of the filter paper that are on the top of the coffee powder and are not in direct contact are still in a dry state (deliberately injected with water when brewing). This shows that this filter paper can indeed achieve by-pass extraction (the premise that the powder wall has not been washed away).

It is indeed a magical prop, and the reason why this kind of thing can be done is mainly due to the special structural design of the filter paper-lotus leaf bionic structure. As we all know, the lotus leaf is hydrophobic because it has many micron and nanometer particles on its surface, and the particles are filled with air, forming a nano-scale air film. At the same time, its surface is also covered with a layer of wax, it is the joint action of the two, the lotus leaf can not be touched by water, water droplets can only roll on the lotus leaf. The filter paper is made using the same principle, so that it has the same hydrophobicity. But this layer of structure is not unsolvable, as long as we use extra fine solids to intervene and polish to destroy its micro-nano structure, the hydrophobicity will be reduced. The addition of coffee powder can achieve this goal! Through the combination of coffee powder and water, the hydrophobicity of the filter paper is broken when cooking and tumbling, so the coffee liquid can seep out.

In addition, high humidity environment and high acidity liquid can break this layer structure. That's why the liquid seeped out of the filter paper when we tested it with hot water and coffee liquid. It's just that their "destructive ability" is not so strong, so the infiltration rate is very slow. Okay! Then, Qianjie will actually explore the difference between coffee brewed with it and conventional filter paper, conventional non-woven filter paper and flow rate.

In the brewing experiment, three pots of coffee will be brewed in Qianjie this time, using conventional wood pulp filter paper, non-woven filter paper, and this special non-woven filter paper. As the latter two have the advantage of oozing oil, the coffee beans used in front street will be the most roasted-Sumatran gold Mantenin.

The cooking parameters are all the same, as follows: amount of powder: 15g grinding degree: 11 degrees of Ek43, 75% oversieving rate of No. 20 sieve, ratio of coarse sugar grinding water: 1:15 water temperature: 88 °C cooking method: three-stage use of filter cup: Kono that cooking process skipped, we directly check the results!

It can be seen that when cooking and baking beans, the flow rate of this special non-woven filter paper is not as fast as the conventional non-woven filter paper, and it will be closer to the wood pulp filter paper. So when we use it to brew deep-roasted coffee, we can apply the original parameters to brew. On the other hand, the conventional non-woven filter paper has insufficient extraction due to the fast flow rate, so we need to properly adjust the grinding of the coffee powder in order to extract a qualified cup of coffee (just the parameters are wrong, not the filter paper is not good. Conventional non-woven filter paper also has a slow version).

Then, because the gap of this special non-woven filter paper is moderate, it will not be as small as wood pulp filter paper, nor as large as conventional non-woven filter paper, so it can filter out only grease without bringing out fine powder. This enhances the aroma of the coffee while retaining its cleanliness (regular non-woven filter paper releases a little fine powder). Therefore, it is more like a filter paper that combines the characteristics of the two (wood pulp filter paper and conventional non-woven filter paper).

But it has two disadvantages: one is that the price is not very cheap, which is 2 to 3 times the price of the first two. It's OK if you buy it for fun, but if you want to put it into practical use, you still have to measure whether your wallet is strong enough (maybe that's not its drawback. Secondly, because the flow channel of the liquid is limited, when we brew shallow roasted coffee, the water is very slow because of the high density powder bed, and then superimposed by the filter paper itself, the launching speed will be even slower. If the flow rate is increased by adjusting grinding, it is easy to produce insufficient extraction, so it is a little unfriendly for novice friends. Well, the above are the only two shortcomings, and other aspects are quite good.

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