Harry Potter: My Life as Hermione’s Houseguest

"Professor Snape, you're our very first venom customer! For you, we'll do a special: just one hundred Galleons per pint!" Qin Yu announced with a bright, businesslike grin, hand extended expectantly.

For all his earlier bravado, Severus Snape found himself nursing a headache as he stared at the boy's outstretched palm. He'd never expected this child to be so shamelessly skilled at asking for money.

"…I'll take two ounces for now," Snape muttered, producing a slender glass vial from his robes. His lips twitched in irritation.

"If you're short on cash, Severus, I could always lend you some!" Professor Swinton chimed in, his tone teasing as he watched the scene unfold.

"Professor Swinton, I hardly think we're on borrowing terms. Besides, my potion research only requires a single ounce. I'm buying two just for emergencies!" Snape shot back, voice clipped and eyes narrowed.

"No problem, Professor Snape! Two ounces, coming right up!" Qin Yu replied smoothly. He could tell Snape was low on funds, but he'd never embarrass a customer—especially not his first. Two ounces might be a small sale, but every business had to start somewhere.

He accepted the vial from Snape and had Hagrid fetch a one-ounce measuring ladle.

But just as Qin Yu was about to draw venom from the nearest jar, Snape raised a hand to stop him.

"Wait. Not that one. I want the venom from over there," Snape said, pointing at the jar on Qin Yu's right.

Qin Yu hesitated, frowning. "Is there a difference between the two, Professor?"

"Of course there's a difference! That jar holds venom from juvenile Acromantulas—see how it's tinged yellow-green? The one I want is a pure pale green, from spiders at least ten years old. The toxicity between the two is worlds apart," Snape lectured, voice brimming with seven parts pride and three parts disdain.

George and Fred crowded around, peering into the jars with baffled expressions. To them, the venom all looked the same shade of… well, slime.

Qin Yu could only vaguely make out a difference, and even then, he wondered if it was just his imagination.

Hagrid was completely lost, squinting at the jars and seeing no difference at all.

"You can really tell them apart, Professor?" Qin Yu pressed.

"Obviously." Snape's reply was cold and impatient.

But Qin Yu paid no mind to the sour look. He shoved the vial and ladle into George's hands, then bounded over and grabbed Snape's hand in both of his, beaming. "That's fantastic! Professor Snape, you've just saved us from a huge loss! We would've never known the difference otherwise!"

Truth be told, Qin Yu hadn't known a thing about venom grades, but he recalled they'd started milking the biggest Acromantulas first—since their venom sacs were easiest to find—filling one jar before moving on to the next. The result? Their venom was accidentally sorted by age and potency.

Now that Snape had pointed out the differences, Qin Yu was more than happy to take his word for it.

Snape stiffened at the sudden contact, then wrenched his hand away with a look of deep disgust. "Don't touch me! And don't talk nonsense—I haven't done anything."

Unfazed, Qin Yu just chuckled and rubbed his hands together. "Here's the deal, Professor: help us with a little favor, and those two ounces of venom are yours, free of charge!"

"…"

Snape blinked in surprise. Was there really such a thing as a free lunch?

Professor Swinton, who'd been watching the whole exchange, glanced from the jars to the two of them, a knowing smile flickering across his face.

…

Qin Yu's request was simple—at least for a Potions Master like Snape: help them sort the venom by grade.

The boys had planned to sell all their Acromantula Venom wholesale to Diagon Alley merchants, assuming it was all the same. If not for Snape's expertise, they'd have sold their most valuable product for a song.

Once he realized the value of his knowledge, Snape decided to make himself even more indispensable. He set about dividing the three jars of venom into four distinct grades.

Three jars divided by four grades? No problem for the great Professor Snape.

Qin Yu and the others watched, spellbound, as Snape began his demonstration.

He identified the best batch as S-grade, the worst as C-grade, and set aside the one in the middle.

With a flick of his wand and a muttered incantation, the venom in the jar began to swirl. After a moment's observation, Snape waved his wand again, and the liquid split neatly in two—like a knife slicing through water.

The sight left Qin Yu, George, and Fred speechless. Even Hagrid and Professor Swinton looked genuinely impressed.

"Well? Don't just stand there—take one half out!" Snape barked at Qin Yu.

He hurried to scoop out half the divided venom with a large ladle, transferring it into an empty jar.

"Professor Snape, that was incredible! You're like the modern-day Lu Yu!" Qin Yu blurted, unable to contain his excitement.

"Lu Yu? Who's that?" Snape frowned.

"Er… an ancient Chinese potioneer. Famous for brewing potions with tea," Qin Yu improvised on the spot.

"Ah, tea. An excellent potion ingredient—I use it often," Snape said with a rare nod of approval.

And so, Snape expertly sorted their venom into S, A, B, and C grades. For his two-ounce "fee," he even helped them decant the venom into clear glass vials.

When all was done, Qin Yu kept his promise, giving Snape one ounce each of the B and C grade venom.

…

Watching Snape leave Hagrid's hut—face as frosty as ever, but with a definite glint of satisfaction in his eyes—Swinton couldn't help but laugh.

"What's so funny?" Snape growled, frowning.

"Oh, nothing. It's just impressive—this clever kid got a Potions genius to work for him all afternoon, and all it cost was a splash of venom. And you seemed to enjoy every minute," Swinton teased, eyes twinkling.

"Hmmph. I simply performed labor equal to my compensation," Snape replied coldly.

But was he happy? Well, anything involving potions always put him in a better mood.

…

"If we'd just sold everything wholesale like we planned, we would've lost out big time. Thanks to Professor Snape's grading, we can price the venom by quality. At least the best stuff won't go for bargain bin prices…" Qin Yu explained to his three "partners." They quickly understood the logic.

Next, Qin Yu had them fill a dozen tiny vials—just a few drops each—to send as samples to prospective buyers in Diagon Alley.

By the time they finished, it was nearly dinner.

Qin Yu and the Weasley twins declined Hagrid's dinner invitation in perfect unison, fleeing the hut before he could insist.

Still, Qin Yu doubled back to grab the magical creatures book Hagrid had promised, then made his escape for good.

… Dimensional Wall …

Translator's Note:

The "Lu Yu" reference comes from a Chinese legend about the Tang dynasty scholar Lu Yu, famed for his expertise in tea. In one story, he could instantly distinguish and separate different waters for brewing tea—a feat Qin Yu likens to Snape's magical sorting of venom. The parallel is a playful nod to both Eastern lore and Snape's potions mastery.

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