Vol. I · What Cooking Does Plate 7 of 10seasoning, salt, tasting, feedback, perception, dilutionF

Taste, Then Adjust.

A cook seasons the way a thermostat holds a room: measure, nudge, measure again — in small steps, because the response is steep.

No recipe can tell you exactly how much salt a soup needs: the stock may already be salty, the vegetables sweet, your palate used to more or less. So cooks season by feedback. Taste, add a little, stir, wait a moment, taste again. It is the same loop a thermostat runs, and it fails the same way if the steps are too big — you overshoot.

Salt makes overshooting easy because perceived intensity grows faster than concentration: the rise from 0.6 % to 1.2 % salt feels like much more than doubling. The workshop seasons a litre of soup and lets you rescue an over-salted one by adding liquid.

Below: how salty a litre of soup tastes as salt is added (intensity in multiples of the threshold, a teaching model following Stevens's power law), with the band most people find well seasoned; and the effect of adding unsalted liquid.

What you will learn
Workshop
Salt concentration of a 1 litre soup as salt is added, and its perceived saltiness (multiples of the detection threshold, intensity ∝ concentration^1.3). The shaded band, 0.8–1.2 %, is where most soups and sauces are found well seasoned.

Small steps, because the curve is steep

Nine grams of salt in a litre is 0.89 % — inside the band most people call well seasoned. Doubling the salt from 0.6 % to 1.2 % does not double the saltiness: by the power law it multiplies it by 2.46. A cook who adds the second half of the salt in one go, tastes, and finds it "a bit flat" will add more and overshoot. Add salt in pinches, stir, wait for it to dissolve and spread, and taste again.

Twenty grams makes 1.96 %, which most people find too salty. There is no ingredient that removes salt; acid, sugar and fat change how it is perceived (Vol. XI) but do not take it away, and the old advice to add a potato does almost nothing. The honest fix is to dilute: 700 mL of unsalted liquid brings the soup to 1.16 %, at the cost of more soup and a thinner flavour that then needs building back.

At the stove

Make a cup of plain stock or water with a stock cube left out. Add salt a quarter of a teaspoon (about 1.5 g) at a time, stir, and taste after each addition. Note the step at which it changes from "flat" to "seasoned", and the step at which it becomes "salty". The gap between those two steps is smaller than most people expect.

Professional kitchens often keep salt in a open dish beside the stove and season with the fingers, because a pinch is a consistent, small amount and can be felt as it is added; shaking from a closed salt cellar is how overshoots happen.

Terms

Seasoning
Adjusting salt, acid and other flavour so a dish tastes complete; done by tasting.
Threshold
The lowest concentration at which a taste can be detected.
Power law
Perceived intensity rising as a power of concentration; for salt the exponent is above one.
Dilution
Adding liquid to lower a concentration; the only way to take salt out of a dish.
Season by small steps and repeated tasting: saltiness rises faster than salt, and nothing but dilution takes it back out.

Sources

  1. S. S. Stevens, Psychophysics, Wiley, 1975: taste intensity grows as a power of concentration; exponents near 1.3 for sucrose and sodium chloride. The course uses teaching exponents near the published ones.
  2. A teaching value chosen for the course: the right order of magnitude and shape, not a measurement of a particular food.