Recently, Qianjie saw such a brewing puzzle: "For the extraction of espresso, is the pressure of the brewing head greater when it is cold than when it is hot?" ”
Qianjie guessed that the friend's implication should be whether the handle at different temperatures will affect the extraction of espresso, and whether to adjust the strength of the press. In that case, let's do a round of experiments.
In this experiment, Qianjie changed the temperature of the handle, fixed the powder amount and liquid weight, and recorded the time variable for comparison, and other controllable parameters were kept as consistent as possible. The extraction time, the strength and flavor of the espresso, and the taste characteristics of the espresso when mixed with the same amount of hot milk are recorded.
Grinding scale of Galileo grinder: 20
Handle: Bottomless.
Coffee machine extraction temperature: 94
Coffee powder size: 20 grams.
Concentrate weight: 38 grams The handle temperature is divided into three: high temperature handle, normal temperature handle, and low temperature handle. (The low-temperature handle will be put in the refrigerator for 1 hour in advance and then used; The heat handle is snapped onto the coffee maker and let it warm up until it becomes hot before being removed).
The experiment used the sunflower warm sun blend coffee beans produced in the front street store, and the flavor of the ideal extraction was: vanilla, hazelnut, caramel, fermentation, and sweet and sour berries, and the flavor of vanilla, cream, and wine chocolate was made into hot milk coffee. The experimental data and results are as follows
Refrigerate the handle: The extraction duration is 30 seconds, and the concentration is 1052%
Concentrated: vanilla, berries, cream, prominent acidity, low body.
Milk coffee: berries, chocolate, heavy milky taste, thin taste.
Preheat the handle: The extraction duration is 29 seconds, and the measured concentration is 1022%
Concentrated: Wine aroma, hazelnut, caramel, tropical fruit sweet and sour, obvious sweetness, full body.
Milk coffee: chocolate, nuts, cream, fermented aroma, rich layersRoom temperature handle: The extraction duration is 27 seconds, and the measured concentration is 996%
Concentrated: Chocolate, fruit acid, slightly bitter, low body.
Milk coffee: hot cocoa, soft taste, slightly astringent aftertaste after cooling, I believe you can notice from the experiment that the difference in handle temperature will affect the extraction of espresso, and there are also differences in flavor performance, but refrigeration and preheating have not caused too much difference in concentration and extraction rate.
By tasting and comparing the espresso and milk coffee, it was found that the preheating of the handle was conducive to improving the extraction of mellow substances in the coffee, and the overall taste was more solid, while the refrigeration highlighted the gentle fruity aroma and brighter acidity. For example, the preheating handle allows the espresso to express a richer aroma and fruity flavor, and the milk coffee has a higher body, which meets our requirements for the extraction of this bean.
Of course, there are other factors that may vary in this experiment, such as the pressure pressure, the state of the coffee beans, etc., and the degree of roasting of the coffee beans will also affect the different effects under temperature changes. But the point of the test is not to find a way to make the espresso taste better, but to verify whether the handle temperature has an effect on the extraction. , the conclusion is: there is an impact!
Back to the question of the friend at the beginning, "Is the pressure of the dough greater when the brewing head is cold than when it is hot?" In the experiment, Qianjie tried to keep the pressing strength of the three tests the same, and the extraction of espresso changed accordingly with different temperatures, so the pressing strength did not need to be adjusted, and the powder was filled and compacted.
As for whether the handle should be preheated in advance or placed at room temperature, Qianjie believes that it should be based on the degree of roasting of the coffee beans we use (whether the flavor trend is sour or bitter), combined with the taste performance of concentrated, American or milk coffee, and then analyze which extraction method (details) is better. After all, the ultimate goal is to make the coffee taste better, right?
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