My first story for Cook's Science is online and boy is it a doozy! I spoke with more than a dozen bartenders to find out how they made their Milk Punch - and it turns out there are a lot of variations and contrasting opinions on how to to do. Hot or cold milk? How much acid is needed? What is the best way to strain it? Is high-fat milk better than low fat?
Milk Punch, as you may know, is a method of clarifying and preserving a punch by curdling it with milk and stringing the curds, so that it's shelf-stable in a cool environment.
They way Cook's Science works is that I did the initial research - talking to all the bartenders - and then their test kitchen tests the theories and tries to figure out the best practical way to achieve great drinks in as much of a controlled environment as they can make. They came up with some interesting confirmations and refutations of bartender Milk Punch lore.
Trying to write about the actual science of it was really challenging, and for that I relied heavy on Dave Arnold's Liquid Intelligence and Harold McGee's On Food and Cooking. I think I understand why milk punch is a clarification method well enough, but honestly I'd love to narrow down why exactly it preserves citrus too.
Anyway, I hope you enjoy the story. It was a big effort and a delight to write.