The inside of the Three-Legged Mottled Brass Cauldron was a dark, ball-shaped chamber eighteen inches in width.
Its inner walls were lined with a tiny fraction of an inch of glassy Dan Yi. The dark, glassy patina formed from forty years of stone and botanical deposits. To a careless potion-maker, this lining was simply old dirt. To Pei Jing, it was a seasoned baked-clay barrier that padded the raw bronze from acid-burning herbal acids and prevented copper leaching into the broth.
He didn’t scrub it with iron wool. He cleaned the chamber with a soft sponge soaked in warm, diluted rice vinegar. He wiped away loose soot specks while preserving the hard, glassy surface beneath.
Old Monster Gui lay propped on his straw pillows in the nook, a wool blanket pulled to his chin. His breathing was shallow, his yellow eyes tracking every motion of Pei Jing’s hands.
“The Jade-Root Ginseng,” Gui croaked, his voice muffled by the linen around his throat. “It must be crushed... To the fineness of flour. If you leave chunks the size of mustard seeds, the core will remain raw while the outside chars into carbon.”
“Flour isn’t enough,” Pei Jing replied calmly. “Particle size must be uniform to within forty hair-fractions. If there’s a wide grain-size spreading, the dissolving rate varies across the batch, producing inconsistent active concentration.”
