Pu’er Coffee

  Introduction: Anyone who’s ever used a hand grinder knows this feeling well — some beans grind effortlessly, while others feel like a full-on workout. Why does that happen? Today, let’s uncover the mystery behind it. When it comes to grinding coffee, there are many factors to consider — origin, processing method, roasting level, and brewing technique. Each of these elements affects how coarse or fine the coffee should be ground for optimal extraction. However, even when using the same grinder, some beans are noticeably harder to grind than others. So, what makes certain coffee beans tougher to grind? 1. Exploring Bean Brittleness Before we go further, it’s important to distinguish between density and brittleness — two terms that are often confused but mean very different things. Density refers to the weight of a single coffee bean divided by its volume. In most cases, we talk about bulk density , which is the weight of a container filled with coffee (minus the container) ...

  Roasters frequently hear crackling sounds when roasting beans. Where do these crackling sounds originate, and why do they occur? Coffee roasting is the process of placing green coffee beans in a heat-resistant vessel and applying heat, which causes a series of physical and chemical reactions both inside and outside the bean. During this process, various flavors, such as acidity, bitterness, and sweetness, are generated, and the coffee's body (mouthfeel) and color are developed, transforming the green beans into dark brown roasted beans. The crackling sounds in coffee roasting are the result of the pyrolysis process occurring during the coffee bean's "First Crack" and "Second Crack." Taking a heat-resistant green bean as an example, the First Crack begins around the 7-minute mark and lasts for approximately two minutes. This sound is low and dull, signifying the onset of pyrolysis, the caramelization of starches, moisture evaporation, and the release of i...