Read The Language of Food: A Linguist Reads the Menu Online
Authors: Dan Jurafsky
By 1662 sherbets were available across Europe. The London coffeehouse Morat’s in Exchange Alley advertised
“sherbets made in Turkie of Lemons, Roses, and Violets perfumed.”
And by 1676 in France, sherbets were the business of
the guild of limonadiers
, in charge of lemonades, iced waters, ices of fruits and flowers, sherbets, and coffee.
The Arabs had earlier brought lemons
and sweetened lemon juice to Sicily and Spain. Although at first lemons were available only to the wealthy, by the seventeenth century lemons were more widely available in London and Paris. Nicolas Audiger, a limonadier of Paris, published
La Maison Reglée
in 1692 with the first French recipe for lemonade:
Sur une pinte d’eau mettez trois jus de Citron, sept ou huit zestes, & si les Citrons sont gros & bien à jus il n’en faut que deux, avec un quarteron de Sucre, ou tout au plus cinq onces; lorsque le Sucre est fondu & le tout bien incorporé, vous le passerez a la chausse, le ferez rafraichir & le donnerez a boire.
Add the juice of three lemons to a pint of water, along with seven or eight zests, and if the lemons are fat and full of juice you’ll only need two, with a quarter pound of sugar, or at most five ounces. When the
sugar has dissolved and is completely incorporated, strain it, chill it, and offer it to drink.
So where did the idea and the technology come from for freezing these sherbets and lemonades to become the fruit ices that we now call sorbets or sherbets? Yes, people had been putting ice and snow into drinks to cool them for over 4000 years, but freezing sweetened fruit juice or cream requires a much lower temperature than just ice can achieve. (Pure water freezes at 0° C, but every gram of sugar added to a liter of water drops the freezing point by about 2° C.) Obviously liquid nitrogen, the darling freezing technology of modernist hipster cuisine, was not available in the sixteenth century.
The insight came from fireworks. In the ninth century, during the Tang dynasty, the Chinese first realized that saltpeter (potassium nitrate) could be mixed with sulfur and coal to create the explosive mixture we now call gunpowder. Gunpowder was quickly adopted by the Muslim world, where
potassium nitrate was called “Chinese snow”
in Arabic.
It was in the Arab world rather than in China that the process of purifying and refining potassium nitrate was perfected, and it was in Damascus that it was discovered, probably by
the physician Ibn Ab
Usaybi’a
, in his 1242
History of Medicine
(
Uy
n al-
nb
)—although he credits a lost work from an earlier Muslim physician, Ibn Bakhtawayh, from 1029—that saltpeter had refrigerating properties: when potassium nitrate (saltpeter) is added to water, it chills the water. Dissolving salts like potassium nitrate (KNO
3
) in water breaks the bonds between the potassium and nitrate ions, but it takes energy to break these bonds, and so heat is drawn from the surrounding water. This endothermic reaction, the basis of the modern cold pack, can drop the temperature of the water enough to freeze pure water, although not low enough to freeze fruit ices or ice cream.
An intimate character study of the Mughal Emperor Akbar, 1542–1605, drawn late in his life
By the early sixteenth century this discovery was widely used in Muslim India to chill water for drinking. At this time most of what is today northern and central India, Pakistan, and Bangladesh, as well as parts of Afghanistan, was ruled by the Mughal emperor Akbar the Great. The Mughals were originally Turkic speakers from central Asia, and the royal line that conquered Delhi traced their descent from Genghis Khan (
Mughal
was the Persian word for “Mongol”), but had adopted the Persian language and culture. By the time of Akbar, the Persian-speaking court at Agra was a center for the arts, architecture, and literature. The Ramayana and the Mahabharata were translated from Sanskrit to Persian during this period, and Akbar’s keen interest in painting and architecture led to the development of styles of art that mixed Persian, Hindu, and European forms. Like many places where scientific and culinary innovation and mixing flourished (Moorish Spain, early Norman Sicily), Akbar’s reign was a beacon of relative religious tolerance, in which the tax on non-Muslims was eliminated and other religions were allowed self-government. Agra was steamy hot (as was his later court in Lahore), and drinks were cooled by spinning a
long-necked flask in saltpeter-water. Here’s a 1596 description from the records of his empire, the
Ain-I-Akbari
:
Saltpetre, which in gunpowder produces the explosive heat
, is used by his Majesty as a means for cooling water, and is thus a source of joy for great and small . . . One sér of water is then put into a goglet of pewter, or silver, or any other such metal, and the mouth closed. Then two and a half sérs of saltpetre are thrown into a vessel, together with five sérs of water, and in this mixture the goglet is stirred about for a quarter of an hour, when the water in the goglet will become cold.
Very quickly this idea of using saltpeter to cool water was adopted in Italy. Blas Villafranca, a Spanish physician working in Rome published the idea in 1550, saying that this saltpeter bath had become the
common method of cooling wine in Rome. The figure on the previous page shows the method, with a bulbous flask clearly adapted from the Indian flasks. This shape makes it easy to turn the bottle in the cold bath, speeding up the cooling.
A goglet and bucket
for cooling, from Blas Villafranca’s
Methodus Refrigerandi ex Vocato Sale Nitro Vinum Aquamque (
“Method for Cooling Wine and Water with Saltpeter”
),
after similar Mughal goglets
In 1589 the next step in ice cream technology was taken by the Neapolitan Giambattista Della Porta. In the second edition of his
Magia Naturalis
he experimented with adding saltpeter to snow rather than to water. The result successfully froze watered wine:
Because of the chief thing desired at feasts, is that Wine cold as ice may be drunk, especially in summer. I will teach you how Wine shall presently, not only grow cold, but freeze, that you cannot drink it but by sucking, and drawing in of your breath. Put Wine into a Vial, and put a little water to it, that it may turn to ice the sooner. Then cast snow into a wooden vessel, and strew into it Saltpeter, powdered, or the cleansing of Saltpeter, called vulgarly Salazzo. Turn the Vial in the snow, and it will congeal by degrees.
Della Porta’s combination was a happy accident; it was not saltpeter’s endothermic reaction with water that caused cooling when mixed with ice, but a completely different chemical property. Adding a solute (a dissolved substance; practically anything will do) lowers the freezing point of water, by interfering with the crystal structure of the ice. Adding salt or potassium chloride slowly draws water out from its crystal mixture, and since the freezing point is lowered, turns into a salty slush. The phase shift from solid to liquid takes energy (another endothermic reaction), resulting in an even colder freezing brine that reaches -20° C, easily cold enough to freeze ice cream or fruit ices.
Sometime between 1615 and 1650, the Neapolitans combined the liquid Ottoman sherbets with the newly invented saltpeter-and-ice freezing method, resulting in a new food: frozen sherbets or frozen sorbets. The idea of freezing other liquids like milks and custards soon followed.
We don’t have any of these early Italian recipes, the way we have early English and French recipes, but evidence for the Italian innovation comes from French ice cream makers like Nicolas Audiger who reported having to travel to Italy to learn how to make ices. Soon afterward the Italians also figured out that common salt worked better than saltpeter for freezing (salt is a smaller molecule than saltpeter; the smaller the molecule, the more ions from each gram of solute interfere with freezing); by 1665 the English chemist
Robert Boyle said that “a Mixture of Snow and Salt”
was the method “much employ’d” in Italy to chill drinks and fruit, “though little known, and less us’d here in
England
.”