Introduction:The "morning test" conducted by coffee shops before opening is a key step in ensuring the daily stability of coffee flavors. This article delves into why even with the same equipment and beans, the flavor of coffee brewed each day can still vary, and provides a detailed introduction to the testing procedures for espresso, lattes, and cold brews. It helps professionals master quality control tips and improve customer satisfaction.
Many coffee shops carry out an internal quality control procedure before official business hours, commonly known as the "morning test." The primary goal of this process is to confirm whether the coffee produced that day meets the expected flavor standards. If any abnormalities are detected—such as unpleasant odors or off-profile tastes—adjustments must be made immediately to ensure customers enjoy a consistently high-quality coffee experience.
Many industry professionals and consumers may wonder: if the machines, water, extraction parameters, and even the coffee beans haven’t changed, why is daily testing still necessary? In reality, especially for espresso, it is highly susceptible to factors such as bean degassing status and ambient humidity, leading to subtle daily variations in extraction conditions. Therefore, the morning test is by no means redundant. In addition to espresso, lattes and cold brews also need to be included in the testing scope to comprehensively monitor the quality of daily output.
The "morning test" conducted before the start of daily operations at a coffee shop is, in essence, a flavor checkpoint for the coffee about to be sold. Through this routine inspection, any flavor shifts compared to the previous day—such as abnormal odors or poor taste—can be detected early, and corrective measures can be quickly taken. Only after confirming that the coffee tastes ideal will the shop officially open for business. However, many people don’t understand: if the equipment, water quality, parameters, and beans all remain unchanged, why would the flavor of the coffee still differ? Is this morning test really necessary?
Why do coffee shops need to conduct a morning test? Taking pour over coffee as an example, since its variables are relatively controllable, under stable operation and consistent extraction parameters, the flavor can usually remain relatively stable, and a morning test may not be needed every day to verify it. But the situation is very different for espresso. Even if all external conditions appear identical to the previous day, the stability of the extraction results cannot be guaranteed. The main reasons can be summarized into two points, the first being the effect of coffee bean degassing on the extraction process.
As is well known, after roasting, coffee beans release a large amount of carbon dioxide and enter a degassing phase that lasts approximately two months. During this period, the beans continuously emit gases. After a whole night of resting, the internal gas content of the beans significantly decreases, which in turn affects extraction performance. For example, a setting that originally used 20 grams of coffee grounds to extract 40 milliliters of coffee in 30 seconds might, due to overnight degassing, only require 25 seconds to complete the extraction the next day. Therefore, the extraction parameters set the previous day may not necessarily yield coffee with the same ideal flavor the next day.
Although the variables caused by the degassing effect are relatively limited, another more critical factor is the change in ambient air humidity. The espresso extraction process is highly sensitive to climatic conditions. The moisture content in the air fluctuates daily, especially under rainy or low-temperature weather, where humidity changes are particularly noticeable. In high-humidity environments, the air is filled with water molecules, which not only easily cause coffee grounds to clump but also affect the extraction pressure of the espresso machine, leading to unstable extraction and making it difficult to maintain the same flavor quality as the previous day.
In addition to conducting daily flavor calibration for espresso, shops typically also test other popular coffee items.
While the performance of espresso is important, its flavor characteristics do not directly represent how it will perform when used to make other espresso-based drinks. This is because different coffee beverages have significantly different flavor requirements for espresso. For example, when making Americano, consumers often prefer a clean and bright-tasting espresso with distinct flavor layers; whereas for lattes, a richer and creamier espresso base is desired. Since these two types of drinks have completely different requirements for espresso, shops usually adjust and confirm the flavor direction of their espresso based on the most purchased items, such as the popular latte. As a result, the latte becomes an indispensable test item in the morning test, alongside espresso.
In addition to espresso-based coffees, single-origin cold brews also need to be included in the daily testing scope. After extraction, cold brews are usually placed in the refrigerator for an overnight maturation and fermentation process. Therefore, the top priority before opening the next day is to confirm whether the flavor and concentration of the cold brew, after overnight fermentation, remain at an ideal level, and to adjust the ice-to-coffee ratio as needed to achieve the best taste. Moreover, although cold brews can generally be preserved in refrigerated conditions for about five days, refrigeration is not a completely sterile environment, so there is still a risk of spoilage. Therefore, throughout the entire shelf life, shops must conduct daily quality checks on cold brews to ensure their flavor and safety are not compromised.
In summary, the morning test procedure in coffee shops is not only a demonstration of responsibility to customers but also a crucial step in maintaining food safety and flavor stability. For professional coffee practitioners, this process effectively reduces the risk of flavor anomalies and enhances overall service quality. At home, one might adjust brewing to personal preference, but in a commercial setting, the morning test is a key step in ensuring that every cup of coffee meets a consistently high standard.
The above content is compiled by CoffeeHunters, a coffee news website.
