Pu’er Coffee

As specialty coffee brewing has become increasingly precise and controllable in recent years, technological innovations have spread across every corner of the field. More and more niche products have emerged as a result. Even something as seemingly insignificant as a filter paper can introduce major variables into the brewing process. Today, filter papers are no longer just about the basic concept of “filtration.” Instead, they have evolved into functional tools designed to adapt to different brewing conditions and scenarios. Some time ago, while discussing the historical evolution of coffee filters, I came across something quite unusual during my research: a product called the Perme coffee filter . I put “coffee filter” in quotation marks because it isn’t actually made from paper. Instead, it’s produced from a blend of polypropylene (PP) and polyethylene (PE) . Today, let’s talk about this rather unique “coffee filter.” I’m pretty sure that by the time you finish reading this intr...

 The coffee we drink is, at its core, water that has dissolved the flavorful compounds inside coffee grounds. In fact, more than 98% of a cup of pour-over coffee is water. We spend so much time chasing the best origins and growing regions, the most suitable processing methods, the perfect roast profiles, and the most precise brewing techniques—yet all of these efforts ultimately rely on water to carry the coffee’s flavor. If we overlook the foundational role of water, everything else can easily fall apart. **No.1 Water Plays Two Core Roles in Coffee Brewing: Extraction and Flavor** Water is responsible for extracting soluble flavor compounds from coffee grounds, and it also makes up the body of the final beverage itself. The chemical composition of the water directly influences what ends up in your cup. **No.2 The Soluble Compounds in Water: Alkalinity and Hardness** Water contains both negatively charged ions and positively charged ions. The concentration of negatively ...