Severus nodded, feigning full understanding. He'd find a library and do a bit of research later. He was perfectly willing to convey to Lily that she was the brightest person on that big blue world.
"Credit... Sounds like they're asking for trouble," he said, leaning into Lily's side, "Do you need anything else to drink? Or something to eat? I don't want to keep you too long, but I can't say I mind the company. At all."
He paused a moment.
"Can I even get what I'd need for brewing here? Herbs, of course... what about more... exotic ingredients. Do muggles have a market for that?"