The coffee machine is most suitable for extracting once. This is because most of the extractable substances in coffee powder have already been precipitated during the first extraction process, and when extracted again, the residual substances are mainly bad ingredients such as wood fibers, which not only fail to provide a good flavor, but may also bring a bitter taste.
Why can't it be extracted multiple times
The precipitation characteristics of coffee components: Most of the volatile substances, soluble substances, and suspended particles in coffee are precipitated during the first extraction process. For example, most volatile substances precipitate within 20 seconds, while soluble substances precipitate about a quarter within 120 seconds.
Flavor changes: Multiple extractions can lead to changes in flavor, taste, and aftertaste. When the residual substances in the coffee powder after the first extraction are extracted again, the flavor and taste will significantly decrease, and may even bring bad taste.
Caffeine content: Caffeine is one of the most important components in coffee, and most of it has already been precipitated during a single extraction process. When extracted again, the caffeine content is already very low.
The extraction process and conditions of coffee are very complex, and the reaction to changes in conditions is also very sensitive. For example, the extraction process of tea is different from that of coffee, as tea leaves can still release sufficient amounts of flavorful ingredients after multiple infusions, while coffee does not.
