Evening Chemistry, Week Nine

I had him down as a time-waster. I'll admit that up front. Twenty-eight, chef's whites under his jacket most weeks, arrived late from a shift smelling of fryer oil, sat at the back, never asked a question. In thirty years of industrial chemistry I'd learned to read a room, and I read him as somebody's condition of employment. Do the course or lose the job. I was wrong, but I didn't find out until week nine. Week nine is buffers. It's the one that loses people. You've spent eight weeks on acids and bases and everyone's just about got the idea that a low pH is acidic, and then you tell them that some solutions resist changing pH and here's an equation with a logarithm in it, and you watch a third of the room decide they'll pick this up later. I did the equation. I did the worked example. I asked if there were questions and there weren't, there never are, and I was about to move on when Marek, at the back, said, "Is that why the mayonnaise splits?" I stopped. "Say that again?" "When you make mayonnaise. If the vinegar's too sharp it splits. Or it won't come together. And if you add a bit of mustard it's more forgiving. Is that a buffer? Is the mustard doing that?" I stood there for a second. Thirty years in a lab and I'd never once thought about mayonnaise. "Partly," I said. "Partly it's emulsification, which is a different thing, we'll get to it. But the pH does matter for the proteins in the yolk, and yes, mustard's got components that'll moderate it. So, partly yes." "Right," he said, and wrote something down, and that was that. Except it wasn't, because after the class he waited till everyone had gone and came up to the front with his notebook, and the notebook was full. Not of my notes. Of his. Diagrams of pans. Lists of what happened when he'd tried things. Temperatures. "Custard curdled at 85, why?" "Bread didn't rise, old yeast or cold kitchen?" Page after page of a man trying to work out his own kitchen from first principles because nobody had ever told him there were principles.

"Nobody at work knows any of this," he said. "The head chef just says do it like this. And I do it like this and it works but I don't know why it works, and if it doesn't work I can't fix it. I just have to start again." "So you came to a chemistry class." "It was this or physics. Physics was Mondays and I do Mondays." I asked him why he'd never said anything in class. He looked at me like it was obvious. "I didn't know if my questions were the right kind." I've thought about that a lot since. The right kind. As if there's a kind. As if I'd have been wasting my time on mayonnaise. We did emulsions the next week, out of order. I brought in eggs. The whole room made mayonnaise in beakers with a magnetic stirrer, and it split, and we worked out why, and Marek stood at the front explaining the mustard to a woman who works at the pharmacy, and she was nodding, and I stood at the side and drank my tea and was, for the first time in a while, entirely unnecessary.