[The science of cocktails]

Because the alcohol molecule has a portion that resembles a fat chain, and aroma molecules generally have the same, alcohol is especially good at extracting and holding aromatics from herbs, spices, fruit peels, etc. That’s no news to mixologists, of course! They have also long used steeping, pureeing, foaming, gelling, and similar kitchen methods for working with liquids. I don’t have any bright ideas at the moment. Anyone else?

[Emulsified Sauces]

More recent work on egg emulsions, which I’ve taken into account in the revision, give greater credit for emulsion stability to the yolk proteins rather than to the lecithin/cholesterol ratio, so low-cholesterol eggs should work just as well. Eggs pasteurized in-shell have suffered a small degree of protein denaturation and so may be somewhat less effective than raw eggs, but in hot egg sauces that’s probably not an issue—the sauce as a whole will get just as hot.

This would be a good experiment to try—making two sauces side by side with the two different eggs, then seeing whether they behave differently. If you do it, please let me know what you find!

[Corked Octopus]

I’ve looked into this, and found no indication in the scientific literature that cork contains anything that could tenderize muscle tissue, octopus or otherwise. I’ve also done the experiment a few times, and found that corks made no difference. In texture or cooking time. They are so light that they ride high on the surface—the contact with the liquid is probably just a few square millimeters per cork, which isn’t much.

[Animal Flesh, Storing in the Fridge]

Thanks, Geoff, I hope you do find the new edition useful.

Regarding meats that have been around for a while—hung meats develop a rancid, microbe-ridden surface too, and that’s one of the reasons that aged meat is expensive. That surface is cut off and there’s a lot of waste. Your precut steaks and chops are almost all surface, and there’s nothing to salvage if it gets slimy and smells off, both signs that you have billions of bacteria helping themselves. Most of those bacteria are harmless, and will be dead anyhow if you fry or grill or braise the meat, but it’s not going to taste very good. The microbes that cause food poisoning—listeria, salmonella, e coli, etc—are not detectable by sniffing or looking. If I were you, I’d keep throwing that old meat out.

[Stews]

Rather than answering point by point, let me try to summarize. The best candidates for stewing are cuts rich in collagen, which dissolves into gelatin and lends succulence to the otherwise dried-out muscle fibers. Fat also does this (and pork shoulder works well because it has lots of both; bottom round has less of both). In stewing tough cuts, you usually want to sear the meat to flavor and surface-sterilize it, then heat it slowly over the course of a couple of hours to allow for some tenderizing by enzymes in the meat, reaching a cooking temperature around 180F, and holding that temperature only as long as needed to dissolve the collagen and get the meat as tender as desired. Overcooking at any stage, including rewarming, can make the meat dry. Acid conditions do help weaken muscle fibers, but in a few hours can only significantly affect the surface. Alcohol will denature surface proteins, but I think boiling it off mainly improves the flavor. Brining will produce moister cubes but also a salty stew.

[Peel This! (or maybe not...)]

Vegetable and fruit peels do often contain higher concentrations of vitamins and minerals, but because the peel usually accounts for a small fraction of the food’s weight, it still accounts for a small fraction of the overall nutritional value. And refined preparations will be less so if they include shards or bits of (usually) tough tissue. Still, if you want to maximize the nutritional value of a fruit or vegetable or grain (or nut, many of which have antioxidant-rich seed coats), then you find ways to include the whole thing. Or serve the skin separately, as in marmalades.

[rare lamb vs rare beef]

Of course doneness in meats is a subjective matter, and I’m curious to hear from others whether there is indeed a consensus that lamb has a higher minimum temperature for becoming palatable.

I’ve never directly compared say a lamb loin and beef tenderloin cooked to the same “rare” temperatures. Sounds like a delicious experiment that I need to do! If there are differences, they might have to do with the distinctive flavor of lamb--I love it but have not enjoyed my encounters with lamb cooked bleu—or with textural differences due to the relative ages of the animals, the younger lamb having more water and immature collagen (I remember the bleu lamb being wet and slippery and chewy).

[Which degree]

I would suggest that you do as much biochemistry as you can stand, since our foods are or were living things, and we in turn live on them. It will help not only with understanding cooking, but also will help you sort fact from fancy on nutritional matters, if that’s of interest to you.

That being said, if quantum mechanics feels right, then do that also or instead! The payoff will be less direct, but studying any science naturalizes you in a rigorous way of thinking, and this will make you a better observer and interpreter of the physical-chemical reactions that you harness in the kitchen.

[Herve This & That]

I’ve known Herve This for more than a decade, have spent several days with him at each of the half-dozen Molecular Gastronomy meetings at Erice, and admire him very much for the energy and gusto with which he collects observations, questions, and theories, and spreads the gospel of kitchen science. Maybe predictably for an Anglo-saxon, I find that some of his work gets pretty abstract and removed from real cooking, but there’s also a lot to be said for any approach that gets us to think freshly about things. Herve does that.

[Contentious Claims]

And my thanks to all of you!

I wouldn’t really say that anything has been contentious, because with cooking above all else, the proof of the pudding is in the eating! Or as another post says, cooks are pragmatists. A lot of people, professionals included, still believe and say that searing meat seals in juices, but when they think and talk through what each of them has seen in every piece of meat they’ve seared and served, they change their minds.

[Why are you doing this?]

Can’t get enough of that kind of pandering!

I explain how I got into writing about food science in the introduction to the new edition, which is pinned at the top of the forum page. Brief answer: the immediate inspiration was a form of expiration.

[Pickled Eggs and more]

The aspect of food preservation that fascinates me is how processes whose primary purpose was to increase “shelf life” were refined into processes that simultaneously increase flavor and pleasure. I don’t think we know who first started pickling food, and I bet that it was discovered in many seacoast places independently, deep in prehistory.

[Letting meat rest after cooking]

Hi Paula, thanks for your kind words, and for your question!

My answer is: it depends. If you finish the cooking at a temperature very close to the final temperature you want in the meat, and the final temperature is close to the serving temperature, then no: no second rest is needed. This might be true for tender cuts of beef or lamb, where you might be shooting for 120 or 130 degrees. However, if you’re cooking pork or a tougher cut to 150 or above, then a second rest will help the meat retain its juices: not redistribute them, but allow the protein structures to reabsorb moisture and become firmer, so that slicing doesn’t squeeze as much out.

[Preservation under pressure]

The pressure is significant in pressure cooking because it’s proportional to the temperature at which water boils: so the higher the pressure in a pressure cooker, the higher the temperature at which the food is being cooked. Typically a cooker maintains 15 pounds per square inch (psi) above atmospheric pressure, which corresponds to a boiling point of around 250 degrees F. This is useful for food preservation because some bacterial spores (a form of these microbes that is designed to survive harsh conditions) can survive long periods at the normal boiling point of 212 degrees. Pressure cooking kills the spores as well as the normal bacteria.

[Salting Water for Vegetable Cookery]

My first copies just arrived, so I hope yours has too. On salted water: it’s sometimes said that salted water boils at a higher temperature and therefore cooks vegetables faster and preserves color. Not true: it takes way too much salt to make a significant difference in the boiling point. However, try the experiment of cooking two batches of vegetables in two pots side by side, one with salted water, one unsalted. The salted water ends up less discolored. That’s because plain water is an osmotically unbalanced cooking medium. Since there’s nothing dissolved in it, it draws substances dissolved in the plant cell fluids—salts, sugars, amino acids—out of the cells, and the water itself flows into the cells, diluting what’s left. With salt pre-dissolved in the cooking water, the fluids inside and outside are more balanced, and less of the vegetable’s substance is drawn out into the water.

So cooking vegetables in salted water helps retain more of the vegetables’ nutrients and flavor. Are the differences significant or easily noticed? It probably depends on the vegetable and how it’s subsequently prepared. I’m not aware of any careful studies of this question.

[dried food, greater flavor]

Thanks for your welcome! That’s a good question. It depends on the food, but drying can create flavor in a couple of ways. One is by enzyme action, something that happens in mushrooms. As the cellular structure is damaged by the drying, enzymes (protein catalysts that act on and change other molecules) come into contact with their targets and generate new molecules, some of which volatile and have aroma, some of which are pieces of proteins and have a savory taste. A second way that flavor is generated is by the reaction of all kinds of molecules in the food, enzymes or not, as they become more and more concentrated in the drying tissue. This is why drying often causes browning at low temperatures: the sugars and amino acids are so concentrated that they react even without the heat of cooking.

Tea is a somewhat different story: enzyme action takes place after the leaves are damaged by rolling but not reallyu during drying; and drying is often done at a high enough temperature to amount to a form of cooking.

[Oil Loving vs. Water Loving...]

Most aroma molecules have both fat-like and water-like portions, and so have at least some ability to be extracted into both fats and oils on the one hand, and water-based liquids on the other. The most volatile molecules, the ones that most readily escape into the air and reach our smell receptors in the nose, are predominantly fat-loving (lipophilic)—otherwise they would be held more tightly in foods (which are almost all water-based). Something to keep in mind—if you extract a fat-loving aromatic into fat or oil, the fat or oil is going to hang onto it and make it less volatile than it would be in water. This means the aroma will be released more slowly, but also more gradually, with a greater persistence. Flavor extraction and release are fascinatingly complicated, and it’s hard to generalize about real foods.

Prego!

[Brining]

Hey, I like those experiments in the Course! Regarding the effects of salt on the muscle proteins, I wouldn’t exactly say they’re denatured in the way that cooking denatures them. Instead, the fiber proteins seem to be disassociated from each other, so that instead of being tightly wound together, there’s more space between molecules, and therefore more room for fluid—and the charged salt ions are both attracted to charged regions of the proteins and help retain the polar (electrically asymmetrical) water molecules. So the muscle tissue soaks up and holds the brine, even when the proteins are subsequently denatured during cooking.

Though I agree that brining can produce meat that is remarkably juicy, I’m not a big fan of it and almost never do it. The meat and pan residues end up much saltier than I like, and the overall flavor one-dimensional. Brining is one effective way of coping with modern low-fat immature meat, but it amounts to making up for the meat’s tendency to become dry by filling it with salt water. For myself, I prefer to cook such meats gently and carefully to make the best of their own flavor and juice as much as possible.

[What's For Dinner?]

I’m glad to be here!

It’s important for cooks to trust their own experience and observations, no matter what book or boss or other form of received wisdom that experience seems to contradict. Facts are facts, and if they don’t fit the received wisdom, then the wisdom needs to be revised. And it’s being revised all the time. Of course it’s trickier to disagree with a boss than with a book!

As I say in the introduction to the new edition, I welcome questions and corrections. The time that I spend reading and writing is time that I’m not cooking, and people who cook a lot have logged more direct experience of foods and their behavior. I’m grateful for their input.

I’m interested in the variousness of foods and cuisines, so I like to explore—but not at the edge of outer space! My mother was born and raised in India, and I’ve had Indian food all my life, love it, and enjoy making it. I’ve also been a big fan of Mexican food since my first Patio TV dinner decades ago, and especially enjoy making moles (which have a lot in common with Indian dishes). I’ve done a fair amount of bread baking, though not so much right now. Weekend slow roasts on the grill are another pleasure. Day-to-day standbys are quick pasta dishes, risottos, stir-fries.

["On Food and Cooking" by Harold McGee]

Boy, talk about burning ears! Many thanks for the interest in my book and for the kind words posted about it. I'm looking forward to the q&a next week--if you have questions for me, please join in.