I’m reading (and cooking) through that massive tome that is Modernist Cuisine, and am currently at Book Two: Techniques And Equipment, Chapter Eight: Cooking In Modern Ovens, Section One: Cooking With Moist Air. It is here they put their first sentence that is entirely in italics: “Humidity governs the temperature at which food actually cooks“. This is an important point, and helps understand why things are cooking the way they are, down to your particular oven and location. This is covered in Book One on the physics of heat and water. The basic takeaway is that transferring heat from air into food is more even and efficient when water vapor is condensing onto cooler food. For example, onto a roast chicken. Let’s observe.