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Harold McGee

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Posts posted by Harold McGee

  1. Thanks--I hope you enjoy the new edition. Milk foams are stabilized by the whey proteins, and skim milk is usually fortified with added whey proteins to provide the body removed when the fat is removed. The whey proteins are most efficient foam stabilizers when they're unfolded--denatured--by moderate heat, and become less so when boiled--they bond to each other and to the casein proteins and so aren't available for reinforcing the bubble walls.

  2. Given your dual interest in science and good food, I would suggest that you look at the Research Chefs Association, whose aim is to promote the marriage of culinary arts and food science in the food industry. Several colleges and universities are now offering programs in “culinology” with the involvement of the RCA. I would also say that the more biochemistry and food chemistry you get under your belt early, the more solid your training will be for whatever path you end up taking.

    And a pitch on behalf of food lovers: it would be wonderful to have scientists who value food quality and diversity as decision-makers in the governmental agencies that increasingly regulate what we can and can’t eat! How about getting a degree in food microbiology and then infiltrating Agriculture Canada or the World Health Organization?

  3. I really haven’t spent much time in professional kitchens—I’ve been stuck in front of the computer to get this book finished! In fact I’m looking forward to getting out and seeing what’s up. But I guess I would say that with or without scientific research, cooks generally know what they’re doing—they know what works, and have done for a long time. Right now I have the feeling that science is contributing to a fresh perspective on cooking, so that it’s not so much going to improve traditional preparations as suggest new possibilities.

  4. You get leathery skin when not enough of the skin’s collagen is dissolved into gelatin, and when the skin doesn’t get a chance to dry out completely. My guess is that you might want to increase the cooking temperature or time or both. And is the box vented at all? If it retains the pig’s moisture, the skin can’t crisp.

  5. It’s not so much the taste of that crystalline form of cocoa fat as its texture, and its stability. Most of the other crystal forms are less compact and stable, don’t form as well integrated a network of interconnected crystals, and therefore have a soft, greasy quality rather than a snappy one. The fat molecules themselves have no flavor.

  6. Cooks can control crystallization and thereby texture pretty well—ice creams, sorbets, candies, chocolate . . . I’m not aware of a treatment of culinary crystallizations as you describe. Flavor probably is affected by nature and proportions of crystals, because they affect the release of the flavors to our palate. For example, flavor molecules that are evenly mixed in a glassy (noncrystalline) candy are more segregated in a crystalline one—pure sugar in the solid crystals that need to dissolve before we can taste it, some sugar plus all the other ingredients concentrated in the syrup surrounding the crystals.

  7. The most laborious rewrite was expanding the original paragraph or two on fish into a 60-page chapter!

    My research for this book had two phases. One was to go through cookbooks and clippings I’ve accumulated from newspapers and magazines, and talk with colleagues, to understand what cooks are working with these days, and the kinds of techniques and issues that they deal with. The second was to immerse myself in the technical literature—food science, biochemistry, whatever was relevant—to understand the basic nature of the ingredients and their behavior. I generally did this by spending a few days per chapter at the University of California at Davis, which has a superb collection of books and journals and online databases.

    Then came the part that I enjoyed most, which was to bring the two phases together and try to illuminate and deepen the culinary perspective by incorporating the scientific.

  8. Alton protests too much! He’s a great communicator and I’m sure has gotten more good kitchen science out to more people than anybody else.

    The acids in wine are “non-volatile,” so they don’t boil off with the alcohol and water, and therefore do get more and more concentrated. Boil wine dry and you’re essentially left with cream of tartar. But the perceived acidity of the sauce depends on the balance of the other components, most of which are also getting more concentrated—the salts, sugars, maybe tannins. So the overall effect might be not that the sauce tastes more sour, but that it tastes stronger. And if the sauce does taste more sour, less balanced, then the cook readjusts the balance by seasoning it.

  9. Thanks for your kind words! Rubs and marinades are great for flavoring meats. In general I find rubs more useful because the usual acidic marinades leave the surface sodden and granular. Brief dry “cures” are good for concentrating and adding flavor, firming texture, and to some extent tenderizing (the salt disorganizes the protein fibrils). Gravlax and duck confit (especially the gizzards, or gesiers) are favorites of mine. In the case of Judy Rodgers’s roast chicken, the salting helps dry out the skin and get it cracklingly crisp.

  10. You’re absolutely right—meat loses juice during cooking no matter what you do to or have around its surface.

    No, I don’t brine chickens or turkeys either.

    Basting can be useful in a couple of ways. It delivers flavor to the meat surface, where it can get concentrated and maybe transformed by browning; and if the liquid includes water, then it cools the meat surface by evaporation, slows the cooking (as does opening the oven to do the basting!), and helps slightly reduce the over-cooking and drying-out of the outer layers of the meat. All that said, it’s also a lot of trouble! Most of the time I don’t bother.

    On vodka in cooking—you never cook out all of the alcohol. Alcohol does have a lower boiling point than water, so you do evaporate a lot of it, but significant amounts remain bound to both the water and fat phases of the dish.

  11. I’m glad you found the chuckles too!

    It’s true that cooking is changing faster than ever, but that’s also due to the shrinking of the globe and the general shortening of the attention span. The scientific, or maybe a better word is “experimental,” approach to cooking, makes it easier to innovate, but the drive for novelty is coming from somewhere else.

    I think that the role of inventive chefs is to invent, not necessarily to follow through. It’s up to the rest of the profession to explore the potential of those inventions to be refined and made into something more than the oddball but trendy dish of the week.

  12. Cooking sous vide is an interesting process in a number of ways, one of them being the microbiology. The FDA was concerned enough about the potential for spectacular food poisoning that in the 1980s they strongly recommended against its use. But those concerns have not been borne out in practice. The way I understand it is that while the cooking temperatures may not be high enough to kill all bacteria and spores, they are high enough to discourage their growth: and then the rapid chilling and continuous cold chain prevent growth during storage. While it may not be essential to maintain the cooking temperature within a degree F or 0.5 C, good temperature control is critical to make sure that the bag doesn’t become an incubator. A water bath set to the same temperature as a combi-oven should produce a similar result.

  13. Do you buy their flour freshly milled? The elasticity of the gluten proteins benefits from oxidation, which takes place naturally over the course of a few weeks after milling. Try letting the flour sit for a while before using it. You can also add "improving agents" that accelerate the oxidation. Ascorbic acid (vitamin C) and fava bean flour are two examples. Comprehensive baking books should give you an idea of proportions.

  14. This idea that saffron can dry out baked goods is news to me, and I don’t see offhand how it could have this effect, particularly in the small quantities in which it’s normally used. It is a dry powder and so absorbs moisture, but the proportion compared to flour would be insignificant. Here’s a wild guess: if some of these baked goods were originally made with a starter of some kind, the saffron might suppress the growth of the lactic-acid bacteria that contribute moisture-holding qualities to starter-raised breads.

  15. You have made your own discovery of "retarding"! Refrigerating the dough slows the fermentation and rising, of course (hence retarding). It also causes the dough gases, carbon dioxide from yeast and nitrogen from air, to seep from the dough matrix itself and collect in larger, coarser gas pockets. (The gases are less soluble in the water-based gluten at low temperatures.) The outer layers of the dough end up less continuous, more divided by bubbles, and the interior is less cakelike, more irregular.

  16. I too am skeptical of the temperature limits set in raw food preparation. The enzymes needed in digestion are digestive enzymes, and they come from our bodies, not from the foods. And any enzymes that might be thought to have health value are very unlikely to get into the body. Our digestive enzymes break enzymes down into amino acids (enzymes are proteins), and any enzymes that survive digestion won’t be absorbed in the intestine. It is true that the levels of some vitamins and other active compounds in foods are reduced by heating; on the other hand, what’s left may be more available because the food structure has been broken down and so is more digestible.

    I did eat at Roxanne’s near San Francisco before it closed, and enjoyed it very much, but more for its inventiveness—making “noodles” from coconut shavings and “flatbreads” from nuts—than for its supposed healthfulness.

  17. There is indeed heat on the seeds, but it didn’t originate there. The capsaicin in chillis is produced and stored in glands on the placenta, the inner pithy structure that supports the seeds. But any manipulation of the chilli breaks the glands and douses the seeds with capsaicin. So most of the heat is in the pith, but there’s always some—and sometimes a lot—on the seeds.

  18. Excellent observation and experiment! Yes, we normally think of browning reactions as a high-temp, dry process, but when the amino acids and sugars are sufficiently concentrated—or the cooking time long enough—they occur at sub-boiling temperatures and in liquids. Another example is the wort—the boiled extract of malt and grains—in beer making. And the white of eggs turns tan when simmered very gently for hours (Middle eastern beid hamin) thanks to the protein and a trace of glucose.

  19. One recent finding of interest is this: the receptors on our tongue that detect the presence of glutamate and other savory molecules are a variant on the receptors that detect the presence of sugars. This makes me wonder whether our taste sensations are as discrete as we usually think about them, whether maybe there is overlap or complementarity among some of them. I’m not sure there would be any practical significance to that, since most of our dishes are already pretty complex mixtures, but it might help us understand some details of that complexity.

    I don’t know of a good print source for glutamate levels, but you can find lists on the web via google.

  20. The reason that you’re having trouble peeling the eggs is that you’re making them too good! Very fresh eggs are harder to peel than eggs a few days or weeks old—apparently a matter of the white pH, which rises with age—and when you cook them carefully to produce a tender white, then they’re tender and easily torn. One thing that helps is to firm the whites by icing the eggs before trying to peel them. Otherwise, use older eggs and/or cook them to a firmer consistency.

  21. I don’t think there’s any way to generalize about salt uptake into foods—it depends a lot on the food, exposure time, and other factors. Potatoes will absorb relatively little salt, and mainly at the surface, because it’s already mostly water; pasta will take up more because it’ll nearly double its weight with absorbed water that penetrates all the way to the center.

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