The functional characteristics of coffee pre-soaking is pre-soaking extraction suitable for all espresso beans

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Guide reading

Pre-soaking refers to the process of reducing the pressure for a short time and slowly injecting water into the coffee powder layer for uniform wetting before the espresso machine pressurized extraction. Pre-soaking can make the powder layer release carbon dioxide ahead of time, making the subsequent pressurized extraction process more stable.

Can all espresso machines be pre-soaked?

No ~ the espresso machine without pre-soaking function is pressurized the moment you buckle the handle with coffee powder and press the extraction button. As soon as the pressurized water will gather in the middle, the powder layer will be extracted by "impact" extraction. The espresso machine with pre-immersion function reduces the pressure at the beginning, allowing the water to be evenly and gently injected into and moisturized the powder layer before pressurized extraction.

(left: low-pressure water injection powder layer state / low-pressure pre-immersion right: high-pressure water injection powder layer state / no pre-immersion)

Characteristics of pre-soaking

| release carbon dioxide ahead of time

Freshly roasted coffee beans continue to release carbon dioxide a few weeks after baking. When coffee beans are ground into powder, carbon dioxide emissions will be accelerated, and bubbles will be formed between coffee particles when water comes into contact with carbon dioxide, which blocks the contact between soluble matter and water, and reduces the extraction rate of coffee. Pre-soaking is through the injection of an appropriate amount of water to guide most of the carbon dioxide emissions, reduce the production of bubbles in the extraction process, and improve the extraction rate of coffee.

| | reduces channel effect |

Espresso machine formally extract coffee when the pressure reaches 9bar, in the pressurized environment of water impact injection, it is easy to lead to cracks between the powder layers. The appearance of cracks will guide the flow of water quickly, and the coffee liquid extracted will become thin and uneven. If there is pre-immersion, the powder layer will become stronger after wetting, can better withstand the impact of water flow, reduce the occurrence of cracks, and make the extraction process more uniform.

So pre-immersion extraction is better than direct extraction?

Not necessarily!

The above characteristics of pre-soaking in Qianjie are based on the premise that pre-soaking should be carried out effectively. Effective pre-soaking means that the injected water can evenly moisturize the powder layer without dripping excess coffee liquid. If the amount of water is too little, the wetting of the powder layer is uneven, some of the powder layer does not release carbon dioxide in advance, which will affect the overall extraction effect; if there is too much water, it will make the powder layer become mushy, unable to resist the impact of the current to form a larger channel.

Although effective pre-soaking can improve the extraction rate of coffee, not all coffee beans are suitable for pre-soaking. If you use medium-to-light roasted beans to extract espresso, try pre-soaking; if you use medium-to-deep-roasted beans to extract espresso, consider whether pre-soaking will increase the chance of scorched coffee while increasing the extraction rate.

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