Grilling Steak
Salt [of the Earth?]

KitchenSavvy Kitchen Science

A frequent response I give when people ask me a cooking  question is, “Try it for yourself and see.” The problem with this reply, however, is that it is not always easy to do. I don’t mean that we don’t have the big science lab to test things out. What I mean is that human beings are naturally inclined to find proof in the face of little or no evidence. The problem is, we don’t structure our tests to find out what is really happening.

In science there is something called the scientific method that essentially says design an experiment, do the test, look at the results and figure out what happened. Try to keep everything else the same, except for the one thing you are testing. [My apologies to all of the real rocket scientists out there who are cringing at the over-simplification. My intention is to outline, not enforce.]

Take for instance the age-old belief that searing meat seals in juices. In his book  The Curious Cook: More Kitchen Science and Lore, Harold McGee describes an experiment done at home with a digital scale, a temperature probe, an electric skillet and slices of eye of round. The reading is interesting. The result is even more interesting: “By the time the meat had cooled down on the plate, the unseared slices had lost about 22% of their weight, and the seared slices about 25% of their original weight.” Exactly contrary to the common belief.

In fairness, he used a postal scale, which may be somewhat more accurate than a kitchen scale. My own kitchen scale is accurate to 2 grams. For a half pound steak (227 grams), that’s just less than one percent, so if I repeated McGee’s experiment with my own equipment, I might have read 23% loss for the unseared steak, an error of 2 grams on the high side, and 24% for the seared, an error of 2 grams on the low side. With only one percent difference between seared and unseared, I would still have concluded that searing doesn’t seal in moisture!

How about putting raw potato into soup an over-salted stew? When Robert Wolke tried that for his book What Einstein Told His Cook: Kitchen Science Explained, he found that “there was no detectable difference in the salt concentrations before and after being simmered with potato.” Being a chemist, Wolke has access to equipment that you likely wouldn’t have at home, but you could still do the same experiment, only relying on your taste buds

But that has a risk. If you expect to notice a particular result, you may fool yourself into finding it. That’s why scientists invented the blind test. No, you don’t necessarily have to be blindfolded. You just have to not know what sample you are tasting.

At home, the experiment would go something like this:

  • Make a stew as you normally would.
  • Divide it two-thirds, one-third. Set the two-thirds aside.
  • Over-salt the other third. Then divide it into halves. Set one half aside.
  • Put some fresh potato slices into the other half and simmer the stew just long enough to soften the potato but not enough so that it falls apart.  Remove the potato slices.
  • Now gather together some friends. Heat equal portions of the salty stew and the salty stew simmered with potatoes. Without telling them what your experiment is testing, let them each have a small taste of each kind and jot down their comments. No discussion until both kinds have been tasted.
  • See if they consistently said the stew simmered with potatoes was less salty.
  • Now, as a reward, let them eat the good stew!

If you think this is too complicated an experiment, you could just wait until you accidentally over-salted something and try it by yourself, setting aside a small sample before adding the potatoes. The problem, though, is that you need to be really, completely honest with yourself and taste with your tongue rather than your beliefs – a very hard thing to do.

Here is another example – in bread recipes your will frequently see something like, “2 1/2 to 3 1/2 cups of flour,” and further on, “the amount of flour will vary depending on the humidity.” To test that out, I put a kilo of all-purpose flour (1,000 grams, about 2 pounds) in a gallon ice cream pail. Each day over a period of a month, some sunny dry days and some wet and rainy, I weighed the flour. The relative humidity over the period ranged from below 40% to over 95%. The weight varied no more than 4 grams or less than one half of 1%. Remember, I said that my kitchen scale is accurate to within 2 grams, so a 4 gram difference was no surprise.

Suppose, however, that my scale was absolutely accurate. Then I might conclude that the 4 gram difference was due to the humidity. In most recipes, the flour to water ratio is somewhere around three to one. For a recipe calling for three cups of all-purpose flour, about 1/3 of a kilo, the moisture difference in the flour, based on my test, would be about 1 1/3 grams or just over a 1/4 of a teaspoon. At a three to one ratio, that would mean that I needed about a teaspoon more or less of flour, not a whole cup. The instructions allow for an error about fifty times greater than what is reasonable.

So the next time you hear or read some food claim you are just not sure about, figure out how you can try it yourself at home. Design an experiment and test your results. You may just be surprised.

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