To better understand the heat grading system at Wooboi Hot Chicken — and by “understand,” I mean determining the point at which I lose all hope for living — I ordered three sandwiches from the Herndon storefront and took them to my car, where I could cough my lungs out in private.

Chef and owner Minwoo Choi has classified his six heat levels — or “power” levels, as he labels them — as “classic” (no heat); levels one, two and three; “code red” and “code blue” (presumably the color you turn when you stop breathing). For my first tasting, I did away with the bottom two grades and jumped directly to the mid- and upper tiers. My order included the Sando with level-two spice, the Clubhouse with level three and the “code red” Thousand Sunny, which is Wooboi’s take on a KFC Double Down, with two fried-chicken cutlets serving as the bread. (Obviously, you can customize each sandwich to your own heat tolerance.)

To me, the level-two Sando is everything you could possibly want from a hot chicken sandwich, save perhaps for the insane amount of Scoville units necessary to prove your alpha-male indifference to pain — and your complete disregard for flavor. My Sando was sprinkled with a 12-plus-ingredient spice blend built around jalapeño peppers, and its heat was ample, stinging the tongue without exterminating its taste buds. The cider coleslaw atop the chicken added crunch and acid to a bite that already had a complexity I couldn’t quite comprehend, at least not until I spoke with Choi. (Hold that thought for now.)

My level-three Clubhouse, a fried-chicken riff on the club sandwich, took the heat to another level with a spice blend that incorporated habanero peppers and mitmita powder, the Ethiopian mixture of bird’s eye chiles, cardamom and more. This sandwich was the first clear indication that I was no longer in Nashville, if indeed I was ever there in the first place: The heat hadn’t yet taken my mouth hostage, but it was starting to paste together a ransom note in preparation. My eyes watered, my nose ran, but I could still taste the sweeter, savory spices embedded on that fried chicken.

One bite into the Thousand Sunny (the cutlets concealed a cache of American cheese and onion brûlée), and I knew I was overmatched. The sandwich was still greasy from its dip in a housemade chile oil, and the spice blend had been applied with a heavy hand, giving the nosh a particularly powdery persona. That’s the last thing I remembered before my Thousand Sunny collapsed into a black hole from which no light or human screams could escape. I felt as if someone had placed a hot poker directly on my tongue. I had to keep my mouth open, like a dog, in hopes that the night air might cool off my inflamed palate. So much water was pooling at the base of my jaw that I worried I might drown. I could taste nothing but my own fear.

The cause of my distress was Bhut jolokia, or ghost pepper, a chile that can be three to 1o times hotter than a habanero. This super hot pepper is the headhunter hiding in Choi’s code-red spice blend, and it had claimed me as a victim after only three bites. Nothing — not money, love or a world without Twitter — could entice me to try a fried chicken sandwich sprinkled with Choi’s code-blue blend, which relies on Carolina Reapers for its heat source. As a point of reference, a Carolina Reaper is twice as hot as the Bhut jolokia, which basically places the former in the same category as pepper spray, and last time I checked, pepper spray is still used as a weapon.

Despite evidence to the contrary, Wooboi Hot Chicken has not been designed as a daredevil stunt, or not just as a daredevil stunt. Sure, there’s a “waiver form” wall on the left as you enter the door that faces Spring Street, and it’s been signed by dozens of seemingly fearless customers, including one diner who added, “DON’T DO IT!!!” It’s sage advice when applied to code-red and code-blue sandwiches. Even the 25-year-old Choi, a graduate of the Culinary Institute of America, won’t stray beyond the level-two sandwiches.

There’s good reason for that: Beyond level two, you lose touch with the complexity built into every sandwich at Wooboi. Choi originally conceived his restaurant as a Korean fried chicken joint, a nod to his ancestry, but he found the flavors too limiting for a chef of his skill set. So his namesake dish splits the difference between the fried chicken of the American South and the one found in Japan. He has developed a proprietary brine that includes, among other ingredients, buttermilk and shio koji, the latter a fermented rice product that brings out the natural umami buried in his free-range, antibiotic-free chicken.

The genius of Choi’s shop lies in the fact that he hides the most elaborate parts of his business from public view: Diners may never grasp the precision behind every spice blend or learn about elusive sweetness in the chile oil or comprehend the transformation that takes place during the overnight brine. They just see the fryers bubbling with peanut oil (those with allergies take note), but they can taste the depth of flavor in every sandwich. Well, in every sandwich that doesn’t leave scorched flesh in its wake.

There are several ways to savor Choi’s mastery with fried chicken, including tenders that can be ordered with a housemade waffle and maple syrup, which fight a losing battle against those hotter pepper blends. At a time when Americans are arguing over their favorite fast-food chicken sandwich, I’ll take Choi’s sneaky hot Sando (level one or two) on a potato bun any day of the week. Maybe paired with fried okra, all crunchy and slimy. Or, better yet, paired with an order of Choi fries, a secret menu item that features waffle fries topped with acidic slaw, crunchy pickles and a remoulade-like sauce. The chef does for fries what he’s done for chicken: amps them up in ways that emphasize their inherent deliciousness.

If you go

Wooboi Hot Chicken

139 Spring St., Suite 1, Herndon, Va., 703-435-3703;

Hours: 11 a.m. to 9 p.m. Monday through Friday; 11 a.m. to 4 p.m. Saturday.

Nearest Metro: N/A

Prices: $2.99 to $12.99 for all items on the menu.