This blog post explores the principle behind decaffeinated coffee maintaining its flavor and how the core technology, the supercritical fluid process, is utilized across various fields.
On my way home after class, I pass countless coffee shops, including Starbucks. Amidst the city’s busy daily life, coffee shops might just be our commas. Like tired office workers on their way home or college students after class, I too naturally pause my steps when passing a cafe, drawn in by the fragrant coffee aroma. When I grab a cup of coffee to find a moment of respite, it often feels like my daily routine is finally complete.
The moment I pass by countless cafes, the enticing aroma of coffee stops me in my tracks. Diverse menus and sophisticated interiors tempt me, and ultimately, I can’t resist the allure. People enjoy coffee that suits their individual tastes. Some prefer strong espresso, while others favor smooth lattes. I tend to choose my coffee based on my mood that day. Today, craving a sweet caramel macchiato, I place my order and look around while waiting for it to arrive. Holding a cup of coffee in my hand, the world suddenly seems a little more relaxed.
I order a cup of coffee, take a photo, and post it on Instagram. Communication on social media has now become an important part of my daily life. I share small moments from my routine, building my own little world. This moment, sipping coffee and enjoying a brief respite, is one of them. Returning home satisfied, I go to bed early to prepare for tomorrow. But perhaps because of the coffee I drank during the day, sleep doesn’t come easily. Who knew a single cup of coffee could have such a big impact? After tossing and turning, I finally fall asleep, only to wake up feeling anything but refreshed the next morning.
On this tired morning, fighting off drowsiness, I grab a coffee milk from the convenience store and head to class. Then, the senior sitting next to me casually says, “Why not try decaf coffee? If caffeine is keeping you up, it might be worth a shot.”
Decaf coffee refers to coffee that has had over 97% of its caffeine removed, allowing people to enjoy the same taste and aroma of coffee while reducing their caffeine intake. Nowadays, cafes easily offer various decaf options. First developed in the 1970s, decaf coffee has seen its manufacturing process simplify, prices drop, and consumption steadily rise. While many immediately associate coffee with caffeine, health-conscious consumers now choose decaf, marking an era where coffee and caffeine are no longer synonymous.
So how does coffee with caffeine removed retain its original flavor? Coffee beans, the raw material, contain numerous chemicals besides caffeine. Only after selectively extracting just the caffeine is decaffeinated coffee complete. The key to this technology, which removes caffeine while preserving flavor and aroma, lies in the ‘supercritical fluid process’.
The supercritical fluid process is a technology combining various scientific principles, used to selectively extract only caffeine from coffee beans. We learned about the states of matter—solid, liquid, and gas—in elementary school, but in fact, matter can exist in another form called the ‘supercritical state’ under specific temperature and pressure conditions. In this state, the substance possesses the properties of both liquid and gas simultaneously, enabling the extraction of caffeine from coffee.
Specifically, when carbon dioxide reaches the supercritical state, it acts as a solvent that dissolves substances like caffeine. Carbon dioxide selectively dissolves only caffeine, leaving the compounds that determine coffee’s flavor and aroma unaffected. As a result, we can enjoy coffee’s rich flavor without the stimulation of caffeine.
This technology isn’t limited to coffee alone. Supercritical fluid processes are also being utilized in various food processing applications, such as extracting sesame oil or rice bran. Furthermore, it is being applied in diverse environmental fields, including eco-friendly dry cleaning without detergents and wastewater treatment technologies.
The potential of supercritical fluid technology is limitless. However, the cost of commercializing the technology remains a challenge. Nevertheless, anticipating the innovative changes this technology will bring, researchers continue striving to discover new materials and methods. Having once thought decaffeinated coffee was merely coffee with caffeine removed, I now enjoy it a little more after learning about the scientific principles hidden within.
Now, every time I drink coffee, I recall the complex process behind it. It fascinates me that even the small tranquility a cup of decaf coffee brings hides cutting-edge technology. Realizing that even a simple cup of coffee, always by our side, holds so many stories, I start my day today, too, by inhaling the aroma of coffee.
