What Is an Espresso and Why Does Rain Affect Extraction?

Rainy weather makes espresso harder to dial in because humidity and temperature shifts change how the puck behaves. With the same beans and the same parameters, extraction on a wet day often runs faster or unevenly, so the shot tastes different. The machine itself is not broken; the surrounding conditions and the coffee have changed.

Understanding what is an espresso helps explain the effect: pressurized water pushes through a compacted bed of fine grounds, so small changes in moisture, grind, and bean condition alter flow. During Guangdong's spring rains, baristas dialing in early shifts notice this most. Adjusting grind, dose, and temperature, and storing beans well, can reduce the variation in extraction.

Spring has arrived, and Guangdong is experiencing continuous rain. For baristas who need to get up early every day to dial in their espresso, this period is undoubtedly a test. Many coffee enthusiasts have noticed that with the same beans and the same parameters, as soon as a rainy day comes along, the espresso machine seems to throw a tantrum, and the extraction results are always less than satisfactory. What exactly causes espresso to be so difficult to dial in on rainy days? This article will analyze the issue in depth from multiple angles—humidity, temperature, bean condition, and more—to help you understand the real reasons behind unstable espresso extraction in wet weather, and offer practical solutions.

As temperatures slowly climb and rain becomes more frequent, it means Guangdong has officially entered the domain of spring. Don't assume Front Street is here to praise the beauty of all things awakening—not at all! With the spring rain drizzling down, those coffee professionals who need to work the early shift and dial in their machines ahead of time are destined to go through a phase of drinking espresso until they're stuffed (Front Street itself is no exception).

The above content is compiled by CoffeeHunters, a coffee news website.