Hi, I have a recipe for mayonnaise, that I suspect is from wartime. It has only condensed milk, sugar, mustard and vinegar. I had no condensed milk so made my own, using fresh milk. And it curdled when I added the vinegar. I made it again using powdered milk, and it did not curdle. And I suspect tinned condensed milk would have no drama. So questions are; Why curdling occurred with fresh but not powdered milk? How much milk should I begin with to make e.g.1 cup condensed milk? How far should it be reduced? And does anyone know the origin of this so called "mayonnaise?"