What Einstein Kept Under His Hat: Secrets of Science in the Kitchen (5 page)

About one person in a hundred is sensitive to sulfites, which can even bring on an asthma attack in asthmatics. Sensitive individuals should avoid foods that contain any of the following: sulfur dioxide, potassium bisulfite, potassium metabisulfite, sodium bisulfite, sodium metabisulfite, and sodium sulfite. Note that, except for sulfur dioxide itself, the tip-off is the suffix
-ite
in the chemical name.

As with all ingested substances, it’s not a simple matter of good and bad. Any chemical is inherently neither “safe” nor “dangerous.” It’s all a matter of amount. The legal limit of sulfites in wine in the United States is 350 parts per million (ppm), although most wines with added sulfites contain only 25 to 150 ppm. According to federal law, if a wine contains 10 ppm or more of sulfites, the label must state that it “contains sulfites.”

With your wine storekeeper’s assistance, look for an FDA-approved “No sulfites added” notice on the labels of some bottles. Your husband can then try them and see if the small amount of natural sulfite is enough to give him a reaction.

And by the way, anyone who says that something “smells like sulfur” probably never took a chemistry course. The solid element sulfur, known biblically as brimstone, is perfectly odorless, but many of its compounds are evil-smelling. Sulfur dioxide is the smell of burning sulfur.

What’s so special about Sherry that makes it a separate category of wine? Is it the grape, the region, the method of production?

....

I
t’s all three, but primarily the method of production.

There are some five thousand varieties of wine grapes that could be used in almost one hundred
appellations d’origine
in France alone, plus seventy-four appellations in California, not to mention Australia, Chile, and dozens of other wine-producing countries. Multiplied by perhaps ten years of vintages, that amounts to over 37 million possible bottles of decent wine—plus untold bottles of plonk. I often wonder how anyone can select the best wine to match a dinner course when faced with such a staggering range of choices lying in a make-believe cellar the size of Antartica.

But I do know something about Sherry, having visited the one place in the world where it is produced: in and around the town of Jerez de la Frontera, a couple of hours’ drive south of Seville in Spain’s province of Cádiz. There, I was figuratively and almost literally immersed in Sherry as I toured the headquarters of Williams & Humbert, producers of Dry Sack, Pando, Canasta Cream, and many other Sherries and brandies.

Why the non-Spanish names Williams and Humbert, you may ask? And whence the English word
Sherry
? Several of the Sherry companies in Jerez were founded in the nineteenth century by British entrepreneurs for the purpose of exporting Sherry to England, where the dry Sherries have always been favored as apéritifs and the sweet ones as dessert wines. The word
Sherry
came into English from the name
Jerez
(HER-eth), but throughout the Spanish-speaking world Sherry is still known as
vino de Jerez
.

So what’s so special about Sherry?

The identity of Sherry is tightly controlled by a regulatory council. To earn the Denomination of Origin “Jerez-Xérès-Sherry,” the grapes must be Palomino, or less commonly Pedro Ximénez or Muscat, and they must be grown within the triangle formed by the towns of Jerez de la Frontera, Sanlúcar de Barrameda, and El Puerto de Santa María. (The regulatory council most zealously excludes the American state of California.) This small region has a unique microclimate influenced by the Atlantic Ocean, the Guadalquivir and Guadalete rivers, and the moist, warm winds from nearby North Africa. Probably the most influential factor in developing the character of the grapes is the area’s chalky, almost white
albariza
soil, which has an unusual capacity for absorbing and retaining air and water.

Of course, many great wines come from exceptional microclimates and soils. But what sets Sherries apart from all others is the unique process by which they are blended and aged.

After the grapes are pressed, the “must,” as the pressings are called, is put into huge stainless-steel tanks to ferment for forty to fifty days at a controlled temperature, achieving an alcohol content of 11 to 13 percent. The young wine then goes into 130-gallon American white oak casks (butts), where the aging begins.

Then comes decision time, when each wine is classified as being suited for transformation into either a dry Fino or a sweeter Oloroso, the two broad categories of Sherry. Finos include Manzanillas and Amontillados, while Olorosos include Cortados and various blends of the very sweet Pedro Ximénez grape. Wines destined to be Finos are fortified (strengthened with added alcohol) to 15 percent alcohol, Olorosos to about 17 percent.

The reason for the difference is that the
flor
(literally, flower), a layer of local, naturally occurring yeasts that forms on the surface, cannot survive at an alcohol concentration higher than 15 percent, and all Finos must serve out their aging time under a layer of
flor
to develop their characteristic lightness and flavor. Olorosos are aged without a layer of
flor
, allowing air to oxidize them to a darker color, fuller body, and stronger nose. (
Oloroso
means fragrant.) Amontillados begin their aging under
flor
and finish after a
flor
-killing fortification to 17 percent alcohol.

During the aging, an intricate blending process unique to Sherries is carried out. Called
soleras
y
criaderas
, it consists of running the wine through a stack of butts containing wines of increasing ages. From the oldest, called the
solera
, one-third of the wine is drawn off for bottling. It is replenished from the next-oldest (the first
criadera
), which in turn is replenished from the next-oldest, (the second
criadera
), and so on, until the youngest wine butts at the top of the stack are “refreshed,” or filled, with brand-new pressings. (
Criadera
comes from the Spanish word for nursery; the
criaderas
are the upper butts in which the younger wines are nurtured.
Solera
refers to the stone floor, where the bottom layer of butts holds the mature wine ready for bottling.)

The complete cycle takes years, with several months of aging time between successive
solera
bottlings. By this method, the young wines gradually take on the characteristics of the older ones, leading to a consistent product that can retain its unique characteristics over a period of decades.

And
that’s
what’s so special about Sherry.

My lady friend was recently visiting me from England. We drank Champagne but didn’t finish the bottle. She suggested that I hang the handle of a silver spoon down into the neck of the bottle before putting it in the fridge. (She saw this on the telly over there.) Believe it or not, the next day the Champagne had not gone flat. How does this work? Would a fork work as well?

....

Y
es, a fork would work just as well. So would a railroad spike. Or a magic wand, for that matter, because the spoon did absolutely nothing. The spoon dodge is pure bunk. Or, if your British friend prefers, humbug and poppycock.

Champagne simply doesn’t go flat as fast as beer and soda do. It would have been just as fizzy the next day without the spoon. All that really mattered is that you refrigerated it. That’s important because carbon dioxide, like all gases, dissolves and stays dissolved to a greater extent in colder liquids.

In order for a dissolved gas to escape from a liquid, the gas molecules must have a microscopic speck of material (a
nucleation site
) upon which to congregate until there are enough of them to form a bubble. The main reason that true Champagne stays bubbly longer is that it is extremely clear and speck-free. If it says
méthode champenoise
on the label, it has been clarified by
dégorgement
—a process in which all sediment is allowed to settle down into the neck of the inverted bottle, after which the neck is frozen and the ice plug, along with the trapped sediment, is removed. Beers are rarely clarified to that extent and therefore lose their fizz more rapidly.

To save your leftover Champagne overnight, refrigerate the bottle with a tight stopper—not tableware—in its neck. You never know when you’ll have even more to celebrate in the morning.

About that tight stopper: You can spend up to $20 for a fancy “Champagne stopper” in one of those shops that cater to winos—uh, I mean wine enthusiasts. It grips the lip of the bottle around which the wire had been wound, and then you screw its rubber disk down tightly against the bottle’s mouth. It’s just great at holding the pressure if you intend to shake up the bottle. But it’s entirely unnecessary in less dire circumstances. The lip and the original wire cage were intended to hold the high pressure of gas produced during the in-the-bottle fermentation. That’s what makes the bottle pop when you pull the cork. But after the bottle has been opened, there’s no such pressure. Any cork or bottle stopper will preserve the residual gas in your leftover Champagne, provided that it is kept cold and unshaken.

(A footnote: Reportedly, a group of scientists at Stanford University in 1994 found that sparkling wine remained bubbly longer when the bottle was left open than when it was re-corked. But they had to do a lot of test-drinking during this prolonged experiment, and their observations may not have been, shall we say, sharply focused.)