How to improve the extraction of sweetness of iced hand coffee?

Compared with hot hand flushing, ice hand flushing gets a stronger coffee liquid by reducing the ratio of powder to water, and then diluting it with ice to make up for part of the extraction rate lost by reducing the amount of water, so the grinding degree is slightly finer than that of hot hand flushing.

Even if the ice hand has made an adjustment to improve the extraction rate, from the point of view of extraction, it is still missing the hot hand punch of the back stage, in other words, "insufficient extraction". Therefore, we will find that when using the same coffee bean, the fullness, sweetness, hierarchy and aftertaste of the hot hand are often better than the ice hand.

As a result, some friends asked Qianjie: is there any way to make iced coffee strong enough, sweet and yet exquisite at the same time? It is true that the requirement is a little high, but it is undeniably a topic worth discussing.

Qianjie has mentioned many times that the release time of a large number of sweet and sour substances is different, and the release of sweet substances often occupies more in the middle and later stages. On the other hand, with less water injection and shorter time, the extraction process may be over before the sweet substances are dissolved. To capture the sweetness in coffee during brewing means to increase the extraction of sweet substances, that is, to find ways to buy it more time to dissolve in water, thereby increasing the proportion of sweet substances in coffee.

The front street here takes strawberry candy coffee beans from Costa Rica as a demonstration, with the flavor of strawberry fudge, ripe tropical fruit and raisins, with a high degree of sweetness recognition, which is very suitable for making ice hands in summer.

Qianjie first tries to extend the extraction time by adjusting the grinding degree (EK43 scale 8.5) (the grinding degree of daily production is 9.5). As the coffee powder fines, the water drops more slowly and the extraction time lengthens. However, due to the high extraction rate due to the fine particles, the aroma and sweetness of the coffee were not improved after diluting and cooling with ice, and showed a slightly over-exquisite bitterness. Therefore, too fine grinding is not feasible.

Then the front street uses another way: water injection into more sections. In addition to the steaming stage, the more the number of lower stages with the same powder-water ratio, the more times of scouring the mixing powder layer, the longer the total extraction time, and the more substances released from each stage. However, the more the number of segments, the less the amount of water injected into each section, and the operation during ice flushing becomes more difficult, so it is necessary to appropriately increase the distributable water volume, that is, to increase the powder-to-water ratio to 1:12. Due to the increase in the amount of water and the decrease in concentration, it is easy to be "tasteless" if the coffee is diluted with ice directly, so Qianjie uses a more luxurious and fast cooling method: over ice.

Test parameters: 91 ℃, 15 g coffee powder, total water 180g, grinding degree EK43 scale 9, four-stage water injection: 30 g + 50 g.

In terms of technique, Qianjie also tries to improve the extraction of coffee substances by adjusting the size of the water flow. First use 30 grams of water to stew for 30 seconds, the first stage of water injection to 80 grams, from the center around the coin-sized small circle of small water to dig out the bubbles

The second stage of water injection to 130 grams, the same small water to the outward circle, try to wash all the powder; the last section of the center fixed point to pull up the flow, water injection to 180 grams. Stop injecting water in 1 minute and 35 seconds, and the time for all the coffee drops to be finished is 2 minutes 05 seconds.

Rinse the extracted hot coffee into a large number of hard ice cubes, repeat several times until the temperature drops to about 5-10 degrees, and finally get about 200 grams of iced coffee liquid.

Then pour the coffee into an ice cup placed in the refrigerator in advance to keep it cool. The strawberry candy flushed out in this way has a very full flavor, smooth taste, and the sweetness of preserved fruit is very clear. the fermented aroma is similar to that of fruit wine, with a hint of flowers and a lasting finish in the mouth.

Of course, the solution tried here is only the result of adjusting the extraction logic of Qianjie and the understanding of the flavor of this bean, not the absolute standard answer. Qianjie believes that there is no omnipotent brewing formula in the world, and the significance of hand brewing is to change the method each time, so that you can get more novel extraction angles, so as to appreciate the more diversified flavor aesthetics of coffee.

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