Change one thing
Say you swap the pan, turn up the heat and use a new oil, and the steak comes out better. Which change did it? You can't know. A kitchen experiment works like any other: change one thing, the variable, and keep everything else the same.
Write down each test
Memory fades. Notes don't. Write down what you changed, the time and temperature, and what you saw and tasted. Run the test twice if you can, since one run might be a fluke from a hot spot or an uneven slice.
A fair test answers your own questions
You don't need fancy gear to learn something new. Take one dish you cook often, pick one thing to change, and cook both versions on the same night. The answer is on your plate.
Test yourself
Questions from the interactive lesson, with the answer and the why.
You want to know whether patting chicken thighs dry helps them brown. Which test works best?
Same pan, heat, oil and time: one dried, one left damp. Only the drying differs, so any browning difference comes from it.
True or false: If you change three things and the dish improves, you can tell exactly which change caused it.
False. With three changes at once, any of them, or a mix, could have caused the improvement.
What went wrong? You test whether salting a steak ahead helps. The salted steak goes in a cast iron pan, the unsalted one in a nonstick pan.
The pan changed along with the salting. Two things differed, so the result cannot be pinned on the salt.
Fill the blank: The batch you leave unchanged, to compare against, is the ___.
The batch you leave unchanged, to compare against, is the control. It is the baseline that shows what your change did.
How many things should you change at once in a fair test?
About 1 things. A fair test changes exactly one thing at a time.
Melted-butter cookies browned darker than softened-butter ones, but they sat in a hotter spot in the oven. What can you conclude?
Nothing firm, since two things changed. Repeat with both trays in the same spot, or swap them halfway.