What's wrong with the slow filtration speed of cold extract coffee? How to increase the water speed of cold coffee?

Summer flames... Hey, forget it, get straight to the theme

! I believe that when making cold extract coffee, we often feel troubled by filtering problems. Because the filtration speed of cold extract coffee can be said to be extremely slow! The reason is that the very fine particles in coffee powder will block the filter paper and reduce the flow channel of coffee liquor, so the filtration time will be greatly extended.

If you only make a single cup of coffee at a time, you can't wait. However, as Jie mentioned in the article two days ago, people will not be so "honest" to make only one cup at a time, but will make many cups at a time to "once and for all." The more components you make, the longer the time it takes to filter. So, is there any way to shorten the filtering time of cold extracted coffee and filter the coffee out quickly? The answer is naturally there! Not only are there, but there are three more! They are all little tricks that baristas have at the bottom of the box! But what everyone needs to know is that no matter which method, in addition to advantages, they all have certain shortcomings, and there is no way to be perfect. So how to choose depends on everyone~

1. Using filter bags/filter cloth to directly isolate coffee powder may be the most familiar method to everyone, because Qianjie often mentions it when sharing the production of cold extract coffee! That is, before starting to soak, pre-pack the coffee powder with tea bags/filter cloth/filter bags, and then throw it into a bottle to mix with water, seal and soak.

As long as we use filter bags for sub-packaging in advance, we can solve the problem from the root cause. There is no need to filter, so how can there be problems of clogging and long filtering time? Then, the purpose of doing so is not only to directly omit the filtering step, but also to effectively increase the extraction rate of the coffee and make the cold extracted coffee brew a stronger flavor (refer to this article for details to learn about the "Portal "). But as Qian Jie said, this filtering method has a disadvantage, that is, it cannot filter out all impurities perfectly like filter paper, and some very fine particles will escape from the filter bag. The existence of fine powder can be good and bad. When the amount is small, it will add a certain degree of mellow degree to the coffee and make the taste more intense; but when the amount is too large, the bitterness will be very obvious, and the coffee will be very annoying to drink.

Therefore, when you use this method to make cold extract coffee, you can observe the final coffee liquid. If the filtered coffee liquor is very turbid or has obvious coffee powder particles, then it is best to use a filter paper cup to pass it over again, which will not take too long; if it is not so turbid and there are no visible particles, then whatever you like~(the third method is the same)

2. The second way to defeat "magic" with "magic" is a bit unique. Why? Because we want to use "magic" to defeat "magic"(coffee powder)! Different from the previous dispensing plan of coffee powder, this plan does not require any adjustments to the production of cold extracted coffee. Just before filtering begins, we need to take the initiative to apply coffee powder from cold extract coffee to the bottom of the filter paper. Don't use too much, just fill in half, and then start filtering.

Qianjie tested and found that the speed of filtering cold extract coffee in this method will be about twice as fast as the conventional filtering method. The principle is very simple, that is, the coffee powder itself is used as the medium to intercept the fine powder. Since our goal is to filter rather than brew, there is hardly much stirring during the entire process. When we spread coffee powder on the bottom of the filter paper in advance, the fine powder that falls to the bottom and comes into contact with the filter paper will be reduced because it is intercepted. Without too much fine powder clogging, there are more channels for coffee liquor to flow, and filtration naturally does not take too long.

The disadvantage of this method is that it is troublesome. First of all, we need to prepare an extra cup to pour out the coffee liquid, and then we can take out the fine powder at the bottom to fill the filter paper. Secondly, we can't use too much force when pouring the coffee liquor and filtering it. Otherwise, when the powder layer is stirred, the fine powder will slip to the bottom to block the filter paper, and the effect will be greatly reduced.

3. Suction filtration The matter of moving tools from the laboratory to coffee for use is not one or two items a day or two, and filtration is one of them. "Suction filtration", also known as "decompression filtration "/"vacuum filtration", uses a vacuum pump or suction pump to form a negative pressure/low pressure in the filtration system, and then allows the solution to quickly pass through the filter paper under the action of a pressure difference. Solid particles are intercepted by the filter paper, thereby achieving high-speed solid-liquid separation. It's easy to understand, we only need to purchase an additional set of suction filtration devices: Buchner funnel, suction filter bottle, and vacuum pump... Then filter, and the coffee liquor can be quickly filtered out. Basically, some large coffee shops or hot coffee shops will use this method to filter, which is simple and fast.

So what are its shortcomings? It is necessary to prepare an additional set of equipment to increase the cost (the price is around 100 - 300). But it is worth mentioning that suction filtration can filter more than just cold extracted coffee. For example, the clarified milk just shared by Qianjie the day before yesterday, or similar slow-filtered liquids can be used to speed up the filtration. In addition to the above three methods, some friends may want to say that you can also speed up the filtration speed by changing filter paper frequently. That is, filter a small portion at a time, and then replace a filter paper. Indeed, this can relatively increase the filtration speed slightly. After all, the channel of the filter paper has been "refreshed." When it comes to the cost, it will use more filter paper and at the same time it will be more troublesome. But no matter which method is used, it can indeed be filtered much faster than a single filter cup filter paper. How to choose depends on you~

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