Book Notes: What Einstein Told His Cook

Robert l. Wolke writes a food column for The Washington Post in which he explains the science behind food, cooking methods, and so on. I read a collection of his columns, "What Einstein Told His Cook", and really enjoyed it. Here is a handful of the interesting parts, paraphrased:

* Caramelization is the heat-induced browning of a food that contains sugar, but no amino acids (which make up proteins). Onions contain amino acids, so technically one can't "caramelize" an onion. When a food with amino acids in addition to sugar is heated to induce browning, such as onions, a set of chemical reactions take place called Maillard reactions. (pg 23)

* White chocolate has no chocolate in it. It is the fat from the cacao bean mixed with milk solids and sugar. (pg 34)

* Salt expose: Salt Sense is real salt, but it can claim to have "33 percent less sodium per teaspoon" because the salt crystals are flaky and fluffy, taking more room in a teaspoon than regular salt. (pg 46).

* His general point about salt is that all types of salt--table salt, sea salt, popcorn salt, kosher salt--are either identical or virtually identical chemically. The only significant difference is the size of the salt grain. (pg 42, others)

* Most European butters have a higher minimum milk fat content, which give them a richer flavor than American butters. (pg 78)

* The point of pasteurization is to heat a liquid to a temperature that will kill or deactivate dangerous microorganisms. Traditional pasteurization, not used much anymore, heats milk to 145-150 degrees F for 30 minutes. Flash pasteurization heats milk at 162 degrees F for 15 seconds. Ultra-pasteurization heats it to 280 degrees F for only 2 seconds.

The ultra-pasteurization equipment heats the milk under a high gas pressure to raise the boiling point of milk and prevent it from evaporation during the process. The process also increases the milk's shelf life by 4-5 weeks compared to flash pasteurization. (pg 91)

* Potato chips bags have opaque windows to keep out ultraviolet light, which speeds up the oxidation process of the fat in chips, turning them rancid. As a general rule, keep all fats and oils out of strong light. (pg 118)

* Green skin and sprouting eyes on a potato are sources of solanine, a toxic alkaloid. The solanine doesn't lie deep, so you can cut these parts of the potato
off and use the rest. (p 119)

* Salt (mixed with a bit of water) preserves food because it kills or deactivates bacteria by osmosis. Osmosis is the passing of water through a membrane to balance out the concentration of water in a 2nd solution. The salty solution sucks out the less-salty water in the bacterium, making it shrivel up and become inactive. (pg 138) I wonder if water could bring a dried-out bacterium to life.

* If you aren't defrosting a home-frozen food in the microwave, put it in a metal pan. Metals are great heat conductors, better than air or water, and will transfer the room's heat to the food faster than those methods. A bowl of warm water changed every half-hour is better for bulky foods, like a whole chicken. (pg 201)

* You can sterilize a sponge by placing it in a microwave and running it for 1 minute. The sponge has to be wet or it could smoke or catch fire. (pg 255) This article, from the original study, recommends two minutes so I would go with that.

* Most microwaves can only operate at full power. When you select "50% power", the microwave is cycling on and off so it is only on 50% of the time. An exception is a microwave with "inverter technology", which can deliver a lower level of power. (pg 256)

* Microwaves can penetrate glass and not metal. The reason the metal grate on a microwave door blocks microwaves is because microwaves are 4 3/4 long, too long to fit through the tiny gaps in the grate. (pg 260)

* The most important quality of a frying pan is heat conductivity. The best heat conductor is silver. (I couldn't find a silver frying pan for sale online though). The next best is copper, which conducts heat 91% as well as silver. Too much copper can be toxic, so the pan will need to be lined with a less toxic metal, such as stainless steel or nickel.

Next is aluminum, which conducts heat 55% as well as copper. The aluminum will need some type of coating to protect it from damage from food acids. The worst conductor among common skillet materials is solid stainless steel, only 4 percent as good as silver.

* He tested how much water button mushrooms absorb when you wash them, and found that it's next to nothing. I've found this to be my experience too, in spite of the warnings against washing mushrooms. (pg 286)

* The reason for different measuring cups from liquids and solids (usually with wider mouths than liquid measuring cups) is to account for how the two substances settle in a container. One cup of a liquids will fill all available space in the container. One cup of a solid like sugar or flour will settle unevenly and leave small caps among the granules. Most measuring cups for solids have wide mouths to let the solids spread out more and fill the spaces between them (more like a liquid).

He mentions a product called a Perfect Beaker that does a good job measuring both dry and liquid substances. (pg 293)