"You're early," Snape grinned. He floated the watch glass over to a softly bubbling size three silver, and tilted the glass. The fluffy cocoons released a fountain of tiny white sparks as they dissolved into the pale lavender potion, calming its bubbling at once. Snape lowered the Bluebell Flame under that cauldron to the slowest simmer, and nodded in satisfaction. "Perfect," he muttered, before he put a lid on that cauldron and turned toward a rapidly boiling size four brass.
"What brings you here?" he asked as he picked up a bone stirring rod.