Pu’er Coffee

 The first time I tried a Dirty coffee served in an ultra-low-temperature ice cup was back in 2023, at UNCLE SHU Coffee in Binjiang, Hangzhou. It was my first real encounter with that striking “hot-meets-cold” contrast, and the experience left a strong impression. Dirty coffee is something most coffee lovers in China are already familiar with. It’s fairly common in cafés across Asia, yet you’ll rarely find it in Europe or the U.S. At its core, a Dirty is simple: ice-cold milk topped with hot espresso. This collision of temperatures creates a dramatic, almost theatrical drinking experience that many people love. In recent years, however, a new trend has taken things to the extreme—using ice cups chilled to −86°C to make Dirty coffee. Compared with a traditional Dirty, which usually uses milk and a cup chilled to around 4°C, a −86°C ice cup paired with espresso at roughly 65–70°C creates a temperature difference of more than 150°C. This extreme contrast delivers a sharper, more int...

 This question is something I’ve noticed quite frequently over the past year while café hopping. Of course, it’s not a new topic for me—I’ve already touched on it multiple times in previous articles. Personally, I’ve encountered it so often that I’ve almost become “desensitized” to the idea of filtering crema from an Americano. But if we take a more rational step back, the reason many cafés now promote over-extraction–style Americanos is fairly clear: they’re chasing a cleaner, more stable, and smoother mouthfeel, while trying to avoid unpleasant flavors. From my point of view, over-extraction–based Americanos and traditional “espresso + water” Americanos follow fundamentally different extraction and brewing logics. In that context, removing the crema can be a 1 + 1 > 2 kind of optimization. However, if it’s just a standard espresso shot that’s brewed normally, then filtered for crema, and only afterward diluted with water, I personally feel it would be better to leave the cr...

 I’ve talked before about “coffee on airplanes,” and anyone who’s been on a long-haul flight knows the feeling—at some point, you just want a decent cup of coffee to stay awake. Unfortunately, what you usually get onboard is instant coffee, to the point where most people have completely given up hope. For a long time, I assumed this was simply airlines trying to cut costs, or maybe a result of limited cabin space that made it impossible to install proper coffee machines. Either way, I never felt I had a truly convincing explanation. Carrying that bias with me, I eventually started digging into the topic. After looking into the details, I finally found some solid reasons that answered a question I’d wondered about for years. So today, let’s talk about why it’s basically impossible to brew fresh coffee with a coffee machine on an airplane. I’m sure many people share this professional—or at least emotional—curiosity. The idea of sipping a freshly brewed coffee at 35,000 feet sounds i...

 As coffee continues to grow in popularity, the places where people enjoy it are no longer limited to homes or cafés. Today, coffee can be made almost anywhere—yes, even in outer space. That’s right: astronauts on space missions can enjoy coffee too. This may not sound like breaking news. In fact, it became possible more than a decade ago. However, relatively few people know the story behind it. So today, let’s take a closer look at the world’s first espresso machine designed for space: ISSpresso . Back in 2015, the Italian Space Agency partnered with Italian coffee company Lavazza to develop the world’s first espresso machine for the International Space Station. The machine was named ISSpresso. In space, due to microgravity, liquids don’t flow the way they do on Earth, making something as simple as drinking coffee extremely challenging. For many years, astronauts could only consume instant coffee squeezed out of pouches—hardly a pleasant or satisfying experience. ISSpresso fund...

 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 ...

 Coffee has long been one of the most important threads running through European history. But what many people don’t realize is that coffee also has its own “dark history.” When coffee first arrived in Europe in the late 16th century, it immediately raised alarm within the Christian church. This black beverage from the “infidel” Muslim world was once condemned as “the devil’s drink.” By the 18th century, this suspicion was still very much alive in Sweden. King Gustav III firmly believed that coffee was harmful to the human body and regarded it as a kind of poison. In order to prove coffee’s dangers, he organized what would later become one of the most infamous human experiments in coffee history. Although the scientific validity of this experiment is highly questionable by modern standards, it nevertheless revealed something remarkable: as early as the 18th century, humans had already discovered that coffee was, in fact, non-toxic. To understand this story, we first need some histo...

 For many people, that first cup of coffee in the morning is the switch that turns the brain on. But more and more coffee lovers are noticing a frustrating change: You used to handle three or even four cups a day without breaking a sweat. Now? Half a cup and your heart is pounding, your chest feels fluttery, and you start wondering: “Is something wrong with my heart?” “Am I really just getting old?” The good news: you don’t need to panic. Coffee-induced heart flutters are usually not a sign of disease. They come from how your body interacts with caffeine. Today, let’s break it all down clearly—so you can keep enjoying your coffee with peace of mind. 1. Heart palpitations after coffee = caffeine doing its job First, let’s get one thing straight: feeling a bit jittery or noticing a faster heartbeat after drinking coffee doesn’t usually mean something is wrong. It’s simply caffeine doing what caffeine does. The main effect of caffeine is activating your sympathetic nervous s...

 Do you still remember CLR CFF, the colorless, crystal-clear coffee that went viral nearly a decade ago? I was lucky enough to actually try that “internet-famous” product back then. For so long, we all believed coffee could be reddish-brown, brown, or even red—but it never crossed our minds that coffee could exist as something completely transparent. When CLR CFF was first released, it immediately caught the attention of coffee lovers. It became the world’s first colorless coffee drink, and its production process was always described in a vague, mysterious way—“made with methods never used before.” It sounded almost mythical, and no one ever seemed to crack the secret behind it. Today, the brand’s social media accounts have gone silent, its official website is no longer maintained, and similar products have essentially vanished. So how did they manage to make coffee completely clear? Let’s talk about this “mysterious” technology. Simply put, the core idea is to keep the flavor and ...

 For many people, that rich, aromatic cup of coffee each morning is more than a ritual—it’s the fuel that jumpstarts the day. But have you ever wondered what happens to your body when you drink coffee day after day, month after month? Today, let’s talk about three surprising changes your body may experience after a full year of consistent coffee drinking. 1. Your Metabolic Rate Increases You may have noticed that a cup of coffee doesn’t just wake up your mind—it seems to energize your entire body. There’s real science behind this. When caffeine enters the body, it gently stimulates the central nervous system and signals fat cells to break down stored fat. At the same time, caffeine boosts adrenaline levels, putting your body into a “ready-for-action” mode that accelerates fat breakdown and energy usage. After consuming caffeine, your metabolic rate can increase by 3%–11% for about three hours. That may sound small, but over time, it means your body burns more energy during...