Facts and fiction about food and cooking, by Peter Aitken
This is another myth that falls into the “suspend the laws of physics” category. That hasn’t happened yet in my kitchen, and if it has in yours then you can probably get on TV. Seriously, to illustrate how ridiculous this idea is without getting into physics and formulas, think of it this way. If you put cold water on to boil, at some time before it boils the water will have become warm. Let’s say it takes time “A” for the water to go from cold to warm. Then after some additional time it will boil – call the time it takes to go from warm to boiling “B”. So, the time it takes the cold water to boil is “A + B” and the time it takes the warm water to boil is “B.” If this myth were true then time “A + B” would be less than time “B” and there’s just no way this could be no matter how many martinis you’ve had. Read more of this post
The surface of guacamole turns brown by reacting with oxygen in the air. The guacamole that is directly under the pit won’t turn brown because the pit prevents air from getting to it. Otherwise, the oxidation process turns the exposed surface brown, just as it does on apples and other fruits. You’ll have much better luck protecting the surface from air by pressing aluminum foil or plastic wrap on it.
Yes, microwaves are radiation, just like the light from the sun, the warmth from a cozy fire, or the signal that brings you radio shows. But, it is nonionizing radiation, which means that it has no effect on food other than heating it up. It has nothing whatsoever to do with the truly dangerous ionizing radiation that is associated with atomic bombs and nuclear power plants.
It’s true that cooking reduces the level of some nutrients, but this is true of all cooking methods. It’s the heat that does it, and with boiling or poaching there’s also the fact that some nutrients are leached out into the water. Microwaves pose no special risk to nutrients and in fact may preserve more of them because cooking times and temperatures may be lower than with conventional cooking methods. Yes, I know that there are many web sites claiming that microwaves destroy nutrients, but they are wrong. Ask these people about their scientific background, may I suggest.
This is one of the very silliest myths but it refuses to die out. There are a lot of people who use their microwave for nothing but boiling water and reheating leftovers and they are really missing out on a lot. I suspect that this myth got its start when microwaves were a new tool and a lot of awful microwave recipe books were published. Some people tried to use their microwave as a general purpose stove and oven replacement rather than as a more specialized tool that is well suited for some jobs but not at all useful for others. For example, you would not want to use a microwave for a roast beef, fried potatoes, or baking bread, but it works just great for things like rice, poached fish, and steamed veggies. I find it particularly handy for making polenta and risotto, with results that are every bit as good as the stovetop with much less work and worry. If you want to expand your microwave repertoire I highly recommend The Microwave Gourmet by Barbara Kafka. Another excellent book is The Moghul Microwave by Julie Sahni (Indian dishes).
The microwave oven certainly has many legitimate uses, but baking potatoes (or anything else) is not one of them. Sure, you can cook a whole potato in the microwave, but what you get is a steamed potato. The crispy skin and fluffy interior of the genuine baked potato require a long cooking in dry heat.
This myth has some basis in fact. Raw milk (milk that has not been pasteurized) contains enzymes that can interfere with the thickening action of milk and the rising of bread. The scalding destroys these enzymes. Today, almost all the milk that is sold has been pasteurized, a process of heating the milk to destroy bacteria. This has the same effect as scalding the milk, so by the time you buy the milk those nasty enzymes are already gone. Unless you milk your own cow, you can skip the scalding.
Scalding can however be beneficial if you are making yogurt or other cultured milk products. Even pasteurized milk contains some bacteria, and they can compete with the yogurt culture and affect the result. By heating milk to 180 degrees you eliminate most of these other organisms and give the desirable culture bacterial a clean slate to work with.
Olive oil has a lower smoke point that most other oils and as a result many people think you cannot use it for deep frying. Balderdash! This would be news to many Italians including the famous TV chef Mario Batali. Olive oil’s smoke point is about 375 degrees and most frying is done below that. Also, just because an oil smokes a little does not mean it is ruined.
Using olive oil for deep frying is undoubtedly expensive. The least expensive olive oil is, in my experience, about twice the cost of other oils that are used for frying such as peanut or canola. Plus you should discard the oil after a single use because the low smoke point means that the oil degrades more during that first use. So, you may never actually want to use olive oil for deep frying, but it is most certainly possible – and can give terrific results for some recipes!
You certainly can use a serrated knife for ripe tomatoes, but there’s no need to. If you find yourself always turning to a serrated knife for this task it is probably because your straight-edged knives are not sharp enough. A well-sharpened regular knife will make paper-thin slices from a ripe tomato—in fact, some people use this as a test for a knife’s sharpness.
It’s become almost an article of faith that gas cooktops are better than electric, and that any “serious” cook should aspire to owning one. This belief does not stand up to intelligent scrutiny, however. Gas cooktops are fine, of course, but when comparing them to electric you will see that there’s no overall objective superiority. Let’s take a look at some of the ways gas and electric can differ: Read more of this post
This myth got its start a number of years ago when medical researchers found elevated levels of aluminum in diseased tissue from the brains of Alzheimer’s patients (dead ones, I hope). One logical possibility (but not the only one) was that the raised aluminum level was responsible for causing the disease. Get exposed to too much aluminum, from your job perhaps or your cookware, and you would have a better chance of coming down with this awful disease. People started avoiding aluminum cookware, and some still are – unnecessarily it turns out. Subsequent research has failed to show any connection between aluminum exposure and Alzheimer’s, and it is believed that the elevated aluminum in the brains of Alzheimer’s patients is a result of the disease process. In other words, high aluminum levels do not cause Alzheimer’s, but rather Alzheimer’s causes high aluminum levels.
Most cooks know that you should start with a hot pan to prevent or minimize food sticking. You may hear a bizarre theory that goes something like this: food sticks to pans because it seeps into minute cracks and pits in the pan and then solidifies when heated, becoming stuck. If you heat the pan before adding the food, the metal expands and fills in the microscopic cracks and holes in the pan’s surface or at least makes them smaller. With fewer or smaller surface defects for the food to grab onto it is less likely to stick.
Unfortunately whoever came up with this idea knew nothing about the physical properties of metals. When metal expands due to heating, each individual atom vibrates faster and faster and thus takes up more space. The result is the same as if each atom simply got a bit bigger, and the result is that the entire piece of metal, defects, holes and all, gets bigger. Thus, if you heat a donut-shaped piece of metal, the outer diameter gets bigger and so does the diameter of the hole. You have probably used this fact yourself when trying to get a metal screw lid off a glass jar. Running hot water over the lid expands the entire lid and loosens its grip on the jar, making it easier to remove. So, heating a pan would cause these hypothetical surface cracks to get larger, not smaller.
Here’s another “common sense” myth that turns out to be false. Alcohol has a lower boiling point than water so it should all evaporate first, right? Nope – that’s not the way it works. The alcohol will evaporate faster than the water but there will still be some left after even extended cooking. The text below shows just how much alcohol is left after different methods and periods of cooking.
The bottom line is that no one is ever going to get tipsy from alcohol in a cooked dish, but people who want to avoid all alcohol for religious or medical reasons need to be aware that some alcohol will remain even after long cooking.
It’s commendable that people do not want to inflict pain on animals, but this one is definitely false on the first account (screaming) and probably false on the second (pain).
As for the “scream,” there’s the problem that lobsters have no throat, no vocal cords, no lungs, so how could they scream at all? The fact is that the noise is caused by air trapped in the shell. When heated it expands and forces itself out through small gaps, causing the sound – sort of like when you force air out between your tightly clenched lips to make a rude sound. Read more of this post
Many people think that “sushi” is synonymous with raw fish. Not so – the term actually refers to the vinegared rice. This is made by dissolving sugar in vinegar (usually rice vinegar) and tossing with the hot, just-cooked rice. Sushi therefore refers to vinegared rice served with other ingredients which may or may not include fish (which in turn may be raw or cooked). The vinegared rice itself is referred to as shari. Raw fish served by itself without the rice is called sashimi.
Some people will tell you that using milk when making scrambled eggs and omelets results in tough eggs – that you should use water instead. It’s puzzling how this myth continues to propagate because it is so easy to disprove for yourself. But if you require the pronouncement of some authority, tests by Cook’s Illustrated (the “America’s Test Kitchen” people) revealed that scrambled eggs made with water are less flavorful, do not fluff as well, and are not as soft as those made with milk. Cream is better still, but that’s another story!
By the way, this advice is for eggs cooked to be moist and creamy, the way they should be. I know some people prefer the dry, fluffy style but all we can do is feel sorry for them.
A common technique in cooking is to use a starch to thicken a liquid such as a gravy or sauce. Wheat starch (flour) and corn starch are perhaps the most common, but potato starch, arrowroot, and tapioca are also used. Does it matter which one you use? Most definitely. These agents differ in five ways.
Now let’s look at how the various thickening agents stack up: Read more of this post
This myth seems to make sense—after all, you use fat to season cast iron and soap removes fat, case closed, right? It’s not that simple.
The seasoning layer on the surface of the pan is formed when the pan is heated while in contact with some fat or oil. This may happen during normal cooking or during a special seasoning process that many people use with a new pan. The result is a chemical reaction in which that fat polymerizes, meaning that multiple individual fat molecules join together to form larger molecules. It is these larger polymer molecules that bind to the metal of the pan and form the seasoning. And, guess what, the polymer is not dissolved by soap. So, it’s perfectly OK to use a mild soap on your cast iron if you are so inclined. Never use harsh detergent, put the pan in the dishwasher, or scrub with an abrasive, however, as these will take off the coating. You also should not cook acidic foods, such as tomato sauce, in a cast iron pan. Read more of this post
This is a very clever and successful marketing ploy by the baking soda people, but the fact is that baking soda is very poor at absorbing odors. It seems to make sense, however, so lots of people have spent untold billions of dollars to put boxes of baking soda in their fridge or freezer to no effect. Activated charcoal would work much better but is expensive. Better to wrap your food and clean the fridge once in a while.
You hear this on a regular basis, mostly from Texans. The fact is that many delicious traditional (and non-traditional) chilis are made with beans and/or tomatoes. Of course, some places do horrid things with chili (may God have mercy on Cincinnati). There is in fact some basis for this myth. Traditional Texas-style chili is usually made without beans or tomatoes, but that’s just one regional variant.
False, but true in a way. The heat in hot peppers comes from a chemical called capsaicin, and most of the capsaicin is contained in the pith, the white material that holds the seeds in place. The seeds actually contain very little. So, you could remove just the seeds from a pepper and affect the heat not at all, but because most people remove the pith along with the seeds, they get the desired result. Although, hot peppers are supposed to be hot, so why would you do this? Another mystery!
Nope. You may want the salt for the taste, but it has no effect on the color of the final product. A pinch of baking soda could actually improve color by making the water more alkaline, but because most people have water that is already a wee bit alkaline to begin with, you may not notice a difference.
Now wait just a minute, how can one statement and its opposite both be false? This is because there are so many divergent opinions about salting pasta water, often strongly held, and none of them is “true” in an absolute sense. Salting does not shorten the cooking time by raising the temperature of the water (it does, actually, but by a tiny amount that makes absolutely no difference). The fact is that salting does one thing and one thing only: it makes the pasta salty (well, duh!). You have to add a good bit of salt to get any real taste effect because most of the salt goes down the drain. There you have it. You want salty pasta, add salt – otherwise, no.
But, there is one situation where I think adding salt is a good idea. For the common tomato-based sauces, the sauce can add the needed degree of saltiness to the dish. With oil-based sauces, however, we face the fact that salt does not dissolve in oil, so the sauce cannot add the needed salt (and the result is often the addition of too much grated cheese to get the desired salt level). Salting the pasta water in these situations can provide a better balance. The same is true of pasta that is destined for a cold mayonnaise-based salad.
In theory, this will work-oil is slippery, after all! In realty, almost all the oil goes down the drain when you drain the pasta and the septic tank beasties will enjoy your good olive oil. Tossing the pasta with a little oil just after draining works much better. But, most sticking problems can be avoided by buying high quality pasta, which sticks less than the cheap stuff, by not overcooking the pasta, and by making sure you are boiling it in enough water. Also, stirring the pasta for 10-20 seconds right after adding it to the boiling water makes stickiness less of a problem.
This old saw has been around for ages, partly because meat cooked over low heat will exude liquid while meat cooked over high heat—seared—appears not to. When you cook meat, the collagen fibers contract and this squeezes liquid out of the meat regardless of the cooking temperature. With high heat, the liquid boils away immediately and you never see it, while at lower temperatures the liquid accumulates in the pan.
Another reason for this myth may be because searing meat that will be stewed, roasted, etc. does indeed give much better results. It has nothing to do with sealing in the juices, however. Careful experiments were performed in which identical pieces of meat were cooked with and without searing. If searing did seal in juices, then the seared meat would lose a smaller percentage of its weight during cooking than the unseared piece. In actuality, both the seared and unseared meat lost about the same amount of weight.
Searing, or more specifically browning, is important because of the Maillard reaction. When the proteins and sugars in meat are exposed to high heat (searing) a large number of chemical reactions take place, resulting in the creation of lots of new flavor elements. It is these flavors, both in the browned surface of the meat and in any pan juices that result, that make searing such an important step in some recipes.
The corn, not the worm! The corn earworm, Helioverpa zea, is the larva, or caterpillar, of a moth. They are almost always one per ear, and inhabit the tip of the ear, feeding on the kernels. I have seen a lot of people at the local farmers’ market rejecting ears of otherwise excellent corn because there’s a worm. What a waste! Organic corn usually has a worm, because spraying with toxic insecticides is the only way to prevent them. All you need to do is cut off the tip of the ear, removing the worm and the damaged kernels, and you’ll be fine. I’d much rather eat an ear of corn that had a worm removed than one soaked with insecticides.
Oh pish-tush! For medium to long-term storage (more than a couple of weeks) this in fact the best place to store coffee. Coffee goes stale mainly because the oils in the coffee (I am talking roasted coffee, whole beans or ground) react with oxygen in the air and go rancid, giving the coffee a stale taste. One way to prevent this is to seal the coffee away from air—this is why coffee in cans and some bags is vacuum packed. The second way is with cold, which slows down chemical reactions. Cold, freezer, duh!
The reason I have heard for not storing coffee in the freezer is that it can absorb odors from the other food. Well, I dunno about you, but I wrap things tightly before they go in the freezer. Even if my leftover garlic and limburger tart comes unsealed, the coffee will be in a jar or zip-loc bag.
There is one situation when freezer storage may not be a good idea, and that when the weather is very humid and your kitchen is not air conditioned. Because moisture condenses on cold surfaces, there’s the risk of the coffee becoming moist when you take it out of the freezer to use. This would likely affect the coffee.
We all know that extra virgin olive oil has the best flavor. But, it turns out that these flavors pretty much all vanish when the oil is heated to sautéing temperatures. If you still want to use olive oil, for the health benefits perhaps, save your money and use a cheaper refined oil, saving the extra virgin for salads, dipping bread, and other non-heated uses. If you want that lovely olive oil flavor on cooked foods, drizzle a bit of the good stuff on after cooking.
