Vol. VIII · Browning Plate 2 of 9dry surface, patting dry, sear, evaporation, steam, browning, marinade, steakHT

Why a Wet Surface Will Not Brown.

Put a wet steak in a hot pan and it hisses, steams and stays grey. The pan is not too cool: the water is in the way.

Water on the surface of food is a thermostat set to 100 °C. As long as there is liquid water on the face touching the pan, the heat arriving goes into boiling it, and the surface stays at the boiling point — far too cool for quick browning (VIII.1). Only when that water is gone can the surface climb to 140 °C and beyond. Every gram of water on the surface costs about 2.3 kJ to remove, energy that would otherwise have browned it.

That is the reason behind three rules of searing: pat meat dry with kitchen paper; let a marinated piece drain and dry before it meets the pan; and do not crowd the pan, because crowded pieces release juice faster than the pan can boil it away (XV.3). The workshop sears one face of a 25 mm steak in a hot pan with as much water on that face as you choose.

Below: the temperature of the face touching the pan over three minutes for a patted-dry steak, a damp one, one dripping from a marinade, and yours (thermal bench).

What you will learn
Workshop
A 25 mm beef steak from the fridge on one face in a pan at about 200 °C (thermal bench). Water on the face is given in grams for a face of 150 cm²; patted dry is about 0.05 g, damp 1.8 g, straight from a marinade 9 g. Browning is the course teaching scale.

Pat it dry

With 4.5 g of water on the face, the surface is held at the boiling point for about 1.2 minutes before it can climb, and after three minutes it has browned to 0.27 on the course scale; patted dry, the same steak reaches 0.52, and straight from a marinade only 0.05, with the face pinned at 100 °C for 1.8 of its three minutes. Meanwhile the inside cooks on regardless, so the wet steak ends with less crust and a grey band at least as wide.

So dry the surface. Pat meat, fish and tofu with paper just before cooking; salt steak well ahead (an hour or a night, XVIII.4) so the brine is reabsorbed, or just before, but not ten minutes before, when it has drawn water out to sit on the surface. Lift marinated pieces out, let them drain and pat them. Dry vegetables after washing. For roasts and poultry skin, a night uncovered in the fridge dries the surface so well that the oven browns it far sooner.

At the stove

Sear two pieces of the same tofu or chicken in the same hot pan, one patted dry and one dipped in water just before. Listen: the wet piece hisses and spits for much longer. Turn both after two minutes and compare the colour.

Chinese cooks dust wet ingredients with starch before stir-frying (上浆, XXVII.4) partly for the same reason: the starch takes up surface water and forms a dry, quick-browning coat.

Terms

Latent heat
The energy needed to turn water to steam without raising its temperature: about 2.26 kJ per gram at 100 °C.
Searing
Browning a surface quickly over high heat.
Dry brining
Salting ahead so the drawn-out water is reabsorbed and the surface dries.
Pinned
Held at one temperature while a phase change absorbs the heat.
Surface water holds the face at 100 °C until it boils away. Dry the surface before searing.

Sources

  1. A teaching value chosen for the course: the right order of magnitude and shape, not a measurement of a particular food.