Doneness Is a Temperature, Not a Time — and Carryover Is Real

Push the probe into the THICKEST part and stop at the centre. Too shallow reads the hot outside and tells you it is done when it is not; too deep comes out the other side into the pan and reads the pan. Avoid bone and avoid fat. Bone conducts heat differently and will read high; a pocket of fat reads differently again. Probe from the side of a roast rather than straight down, which makes it easier to find the true middle. Take more than one reading, in more than one place. The repeat-and-look-at-the-spread rung applies directly: a single probe reading is a single measurement, and the coldest spot is the one that decides whether the thing is safe.

Safety is a combination of how hot and for how long. Chicken at 74 degrees is safe instantly; the same chicken held at 60 degrees for a few minutes reaches the same reduction in bacteria — which is why low-temperature cooking can be both safe and far juicier. Texture follows the same logic in the other direction. A tough cut held at 80 degrees for hours converts its collagen to gelatin and becomes tender; the same cut taken quickly to 80 degrees is simply dry. Time at temperature is doing the work, not the peak. So braising is not a slow version of roasting. It is a different mechanism with a different target, and the thermometer question changes from "has it reached X" to "has it been at X long enough".

Put the probe in a glass of ice and water, stirred, and it should read 0 degrees. Put it in boiling water and it should read 100, less about 1 degree for every 300 metres of altitude. That is a two-point calibration using references nature supplies free, and it is the same idea as the Celsius rung. Many thermometers have an adjustment; those that do not can still have their error written on a label and subtracted. Do it when the thermometer is new, after it has been dropped, and once a year otherwise. A thermometer reading 4 degrees low will have you serving undercooked chicken with complete confidence, and nothing else in the kitchen will tell you.