What Einstein Kept Under His Hat: Secrets of Science in the Kitchen (23 page)

Note that the density of an object can decrease either by the object’s losing weight or by its expanding in volume. When a human object gains both weight and volume, his or her density decreases, because fat is less dense than muscle. Draw your own conclusion.

Another example: In making beignets, or “doughnut holes,” we drop spoonfuls of dough into deep, hot fat. The dough ball is less dense than the oil and therefore floats. But as the portion below the surface browns in the hot oil, it loses water in the form of steam and becomes even less dense. The bottom of the ball is now less dense than the top, and it may actually capsize like a top-heavy boat and proceed to brown its other side.

The first time I saw this phenomenon I was as surprised as if I had seen a pancake flip itself over when its first side was done.

Would you please explain the difference between apple juice, natural-style apple juice, and apple cider? Are they nutritionally identical? Do they have to be pasteurized?

....

I
t depends on where you live. In this country,
apple juice
and
apple cider
are often used interchangeably, referring simply to the liquid that runs out of pressed apples. But in most other countries,
cider
means apple juice that has been allowed to ferment and produce alcohol, just as grape juice ferments to produce wine. We Americans would call fermented apple juice “hard” cider, as distinguished from unfermented, alcohol-free “sweet” cider. To sidestep this ambiguity, we’ll adopt the international nomenclature: if it’s unfermented it’s apple juice, if it’s fermented it’s cider.

The word
cider
and its variations are ancient, originally meaning any intoxicating beverage made from fruit. Because all fruits contain fermentable starches and sugars, and because all you have to do to ferment them is leave them lying around so that airborne yeasts can fall on them, the world’s cultures have come up with a most remarkable variety of alcoholic beverages.

Apple juice may be bottled while still cloudy from suspended particles of fruit, or it may be filtered to clarify it. It’s just a matter of preference. As on most food labels, the word
natural
on a juice label can mean anything the bottler wants it to mean. But in the case of apple juice, it might be intended to mean unfiltered.

There is no federal requirement that apple juice be pasteurized, but many brands are routinely heat-treated to keep them from fermenting. If they haven’t been heat-treated, the labels must say “Keep refrigerated,” so the absence of that warning is your assurance that the juice has been pasteurized. Unpasteurized apple juice left in the refrigerator will become fizzy within a couple of weeks, indicating fermentation. It’s not wise to drink it, though, because the strain(s) of bacteria doing the fermenting are unknown, and the fizz means that they are feasting on sugar, producing carbon dioxide and alcohol, and multiplying like—well, like bacteria. In the reproduction department, rabbits can’t hold a candle to bacteria. (Just a figure of speech. Try very hard
not
to picture a rabbit holding up a candle to a petri dish of bacteria. Whoops! You failed, didn’t you?)

Regarding nutrition, some apple juices, especially the pasteurized ones, are likely to have been fortified with vitamin C. Check the label to see.

Can you straighten out the various alcoholic apple beverages? I’ve heard of hard cider, apple wine, apple brandy, and applejack. Or are they all the same?

....

T
hey differ mainly in the ingenious methods that have been invented to arrive at their percentages of alcohol.

Apple juice can be allowed to ferment naturally by just leaving it around in the open and letting airborne yeast cells fall into it. These microscopic, single-celled plants feed on the fruit sugars, converting them to ethyl (grain) alcohol. It doesn’t take many yeast cells to start the ball rolling, because the more they feed the more they reproduce, growing into voracious sugar-eating machines in a couple of days. But when all the sugar is consumed, the feeding frenzy ends; the alcohol concentration is about 5 percent, about equivalent to beer. That’s
hard cider
, as opposed to—well, “soft” or nonalcoholic cider, which is really just apple juice.

We humans don’t have a monopoly on intoxication. I used to have an apple tree that dropped its apples onto my driveway every fall. The apples would break open and release their juices, which would soon ferment. Bees would be attracted, sip the sweet alcoholic juice, become intoxicated, and roll around in delirium on the ground. I had lots of fun watching this apian bacchanal, but I was kept busy calling cabs to take them home to the hive. (
Don’t drink and fly!
)

In the cider-producing regions of England, France, and Spain—the south of England, the north of France, and the Asturias region of northern Spain—where apple trees thrive and grapevines don’t do very well, ciders are often drunk or used in marinating and cooking instead of wines. The characteristics of different ciders can vary as much as those of different wines. Like wines, ciders can be matched with foods based on their acidity, dryness, and fruitiness, qualities that arise from the specific varieties of apples the cider was made from and how it was fermented.

The dryness of a cider is the extent to which the apples’ sugars have been fermented to alcohol; the driest ciders have had all their sugars used up. The very dry Spanish
sidra
of Asturias, for example, is a particularly good stand-in for dry white wine in virtually all its applications.

A sparkling or effervescent cider, like sparkling wine, has been bottled before fermentation is complete. A highly regarded example of this is the French-style cider (
cidre
), either sparkling or still, with its alcohol content limited to 2 to 5 percent by arresting the fermentation process, either by pasteurization or by the addition of sulfur dioxide.

Very early in the game, humans figured out what was happening to fermenting apple juice and wanted to boost the alcohol content to fuel their paeans to Dionysus. They added more sugar to feed the yeast, eventually also allowing the juice to absorb tannins from the insides of wooden barrels for complexity and depth of flavor. The alcohol content was in this way boosted to between 10 and 12 percent, comparable to that of grape wines. We have now made
apple wine
.

Want still (pun intended) higher alcohol content? Distill the apple wine, just as some wineries distill their grape wine to make brandy. That is, boil the liquid and cool the hot vapors to condense them back to a liquid. Because alcohol evaporates more readily than water does, the vapors and hence the condensed liquid (brandy) will be richer in alcohol than the original liquid (wine) was.

Laird & Company, the biggest producer of apple brandy, distills cider until it is 80 percent alcohol (160 proof), cuts it with water to about 65 percent (130 proof), and ages it in charred oak barrels. It comes out as
apple brandy
. At bottling time it is adjusted so that the alcohol content is 40 or 50 percent (80 or 100 proof) and labeled
applejack
, although strictly speaking it is still a brandy, according to the U.S. Alcohol and Tobacco Tax and Trade Bureau.

The French apple brandy Calvados, a product of the eponymous
département
14 in Normandy, is similarly made by distilling apple wine twice: first to achieve an alcoholic content of 28 to 30 percent and again to reach 72 percent, after which it is “cut” to a more drinkable 40 to 43 percent (80 to 86 proof).

The word
brandy
comes from the Dutch
brandewijn
, meaning burnt (actually, distilled) wine. In France, brandy is known as
eau de vie
, or water of life. I guess it’s a matter of priorities.

I like to buy raw cashew nuts at a health-food store. I sometimes pulverize them to make a tasty milk. But my daughter came home from school telling me that cashew nuts contain a highly corrosive, toxic substance and that they must never be eaten raw. Health food?!

....

T
he succulent “fruits” of the tropical cashew tree
Anacardium occidentale
, often called cashew apples, are about the size and shape of a pear. They are not only edible but quite delicious. Since they are highly perishable, however, you won’t find them very far from the trees. I was lucky enough to taste them when I lived in Venezuela, where they grow and are called
merey
.

A “cashew apple” on the tropical cashew tree,
Anacardium occidentale
. The edible “apple” is known as
merey
in Venezuela,
cajueiro
in Brazil, and
marañón
in most of the rest of Latin America. The cashew “nut” (botanically, the fruit) is inside the lower, kidney-shaped appendage.

Attached to the “apple” at its lower end is the kidney-shaped nut (which, botanically speaking, is actually the fruit), encased in a double shell. Between the shells is a gummy phenolic resin containing the corrosive and poisonous chemicals anacardic acid and cardol, among others. If eaten, this resin would actually cause blisters in the mouth.

Obviously, the poisons must be removed before the nuts are safe to eat. This is accomplished by roasting the unshelled nuts in hot oil, which does two things: it drives off the resins, and it makes the shells brittle enough to crack by hand with a mallet, a method that continues to survive into the twenty-first century. Both the shells and the corrosive chemicals are long gone before you ever see them in the store.

The nuts are perfectly edible at this stage, and are sold as “raw cashews” in spite of the fact that they have already been cooked at 365 to 375°F (185 to 190°C). Commercially packaged cashews are usually roasted again at 325°F (163°C); this roasting softens them and enhances their color and buttery flavor.

Those raw-foods-only restaurants and other raw-food devotees who insist that food must never be allowed to exceed 118°F (48°C) make frequent use of “raw” cashew nuts and “raw” cashew butter in their creations. Either they’re kidding themselves or they don’t know that their nuts were roasted at a much higher temperature long before they saw them.