「Discussion」Can coffee powder be re-ground?

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We all know that coffee tastes best when it is freshly ground and brewed, but if you get a bag of medium-coarse coffee powder as a gift, you might want to grind it into a finer powder, and then use the second-ground powder to make espresso.

No matter how attractive espresso is to you, using pre-ground coffee to brew will not make good coffee even if you re-grind it. It is not recommended to re-grind such coffee. There are several reasons for reference:

Regrinding may clog the grinder

This is the most important point. If the coffee powder is poured into the grinder and ground into finer powder, the powder will not fall smoothly from the grinder's blade like beans. Not only will you not get the desired fine ground powder for espresso, but more powder will remain on the grinder's blade, contaminating the subsequent grinding quality.

In order to remove the residue of these powders and restore the grinding quality, you must also disassemble the grinder and clean the blade thoroughly. Many grinder manufacturers do not recommend customers to disassemble the machine by themselves, and may even not provide warranty services for this reason. When you can't put it back to the original state and you really want to drink coffee, it's not fun at all. Even if you can install it back smoothly, you still need to test and calibrate the grinding degree... It's really troublesome to think about it.

In addition, these second-ground powders are actually not suitable for making espresso. They can only be used for compost, deodorant and dyeing purposes, because the powders in this state are too fine, resulting in the inability of water to pass through the coffee powder to achieve the purpose of extraction.

Re-ground coffee has lost its flavor and is not fresh.

Even if you can adjust the grinder to the right size without contaminating the blade, the re-ground powder cannot produce a full-flavored espresso. The key lies in the aroma. Once the coffee is ground, the aroma will be released in large quantities, and the correct brewing can bring out the flavor of the coffee to the extreme. When you get coffee powder, even if you grind it again, the aroma will be lost in large quantities when brewing.

This is why we recommend grinding the coffee beans just before brewing, and it is best to brew the powder within five minutes. When the coffee powder is ground in advance, even if it is placed in a sealed can or in a vacuum state, the brewed coffee will still lose a lot of aroma and cannot reach its peak state.

Making up for the shortcomings of pre-ground powder by brewing

If you do get pre-ground coffee, the best way is to make up for the shortcomings of the powder by brewing it in a way that is suitable for coarse ground powder. Maybe you have left your French press dusty for a while, this is a good opportunity to use it again and test it with different hand-brewing parameters and methods, but the key point is still how coarse the ground powder in this bag is.

If you want to use medium-coarse ground powder to make espresso anyway, you can use the pressure relief valve on the back of the brewing portafilter to get something similar to espresso. In some coffee machines, this valve can be used to compensate for the lack of pressure caused by coarse powder. Although it won't be a very good espresso, at least the extracted water will flow down.

Cleaning and maintenance of coffee grinder

No matter how good the grinder is, there will be residual powder when grinding, and the residual powder will affect the quality of the coffee powder you grind next time. If you are grinding beans A now, the next time you grind beans B, the coffee powder of A will be mixed in. Therefore, you can prepare a small amount of beans B before grinding beans B to "clean" the grinder. You can also buy a brush and a blower to do basic cleaning and maintenance. It is not recommended to disassemble and clean. Not only will it be impossible to assemble it back, but it may also lose the original warranty qualification.

Regrinding ≠ secondary grinding

Finally, some people may ask, isn't the secondary grinding used by Japanese contestant Miki Suzuki in the 2017 Seoul Barista Competition just re-grinding? Why can she do it? Because Suzuki's idea is to increase the surface area of ​​the ground coffee particles as much as possible through secondary grinding, so that the flavor and touch have their own space. In fact, what she really does is frozen coffee beans + secondary grinding, which is very demanding on coffee beans and grinding utensils, and has poor applicability. It is not suitable for daily production or tasting at home. You can learn and understand her operating concept, but it is not recommended to copy and generalize.