Salted_ A Manifesto on the World's Most Essential Mineral, With Recipes - Mark Bitterman [36]
FIRE EVAPORATED SALTS
In places where rough terrain makes solar evaporation impractical, or where inhospitable climate makes it impossible, fire can be enlisted to accelerate the evaporation of water. A tremendous variety of salts can be made by fire evaporation. Coarse granular traditional salts are possible, but often as not the salt maker takes advantage of the highly controlled environment to make something more unusual.
A salt maker re-creating a Lewis and Clark salt-making camp, Seaside, Oregon. Every year, the Lewis and Clark Museum in Seaside, reenacts the explorers’ saltmaking enterprise, undertaken to provision the party for the long return voyage to the eastern states.
This salt was tinted a copper-oxide blue from the unlined pots used to evaporate the salt. The original expedition would have had zinced or tinned pots to make a salt described by Lewis as “excellent, fine, strong, and white.”
Rapid boiling produces large, parchment-fine flakes. Slower simmering produces shio, the fine-grained salt mastered by the Japanese. Shio crystals are the most delicate of all salt crystals, perfected by continuous, carefully studied stirring. The gentle agitation of brine densely saturated with sodium and magnesium salts induces downy tufts of salt so fine they seem made up of single molecules. A few artisan salt makers crystallize their salt in a mold, drying it completely to yield a puck or ingot reminiscent of the salts made using briquetage, pottery shards, hundreds of years ago.
Collecting seawater or brine from a salt spring and boiling off over a wood fire is a common and ancient form of salt making. It is also the best documented. Pottery shards found in large quantities at many Neolithic settlements across Europe and Asia, once thought simply to be discarded ceramics, are now believed to be broken briquetage pots used in the boiling off of brine to make salt.
Modern artisan methods for evaporating salt have not changed much, though certain conveniences have been adopted, such as the filtering and/or purifying of seawater beforehand. Some very creative, high-tech evaporators have harnessed geothermal energy. Salt makers in some countries avoid heat altogether in favor of electricity-based techniques like ion-membrane separation. But such methods generally yield salt that has been robbed of its soul, its ties to nature severed. It is difficult to think of such salts as artisan, regardless of the salt maker’s intentions.
Artisan or otherwise, salts made with fire require considerable input of natural resources. It can take as much as two tons of liquid fuel to make one ton of salt. The huge industrial solar saltworks at Rio Tinto in Australia produce 6.1 million metric tons of salt a year by evaporating 1.1 million metric tons of saltwater (290 million gallons, enough to fill 18,000 residential swimming pools) every day. The company estimates 14 million tons of coal would be required daily to achieve the same result. As outlandish as that may sound, consider that seawater is just 3 percent sodium chloride, so more than 30 tons of water must be boiled or simmered off to make that ton of salt. Nonetheless, fire evaporation has a long and distinguished place in our history, and the fire evaporated salts that have survived the industrialization and subsequent hyper devaluation of salt can achieve extraordinary culinary heights. Like a fluffy chocolate mousse, a blazing flambée, or an architectural salad, our awareness of the food is heightened despite the artificiality of the process—or indeed because of it. Turning your back on fire evaporated salt would be like turning your back on gin or hamburgers or pasteurized milk: they all require fuel to produce, and yet their deliciousness makes them indispensable.
INDUSTRIAL FIRE EVAPORATED SALT
In industrial settings, vacuum evaporators—and some artisanal ones—are used to improve fuel efficiency. Water is boiled in a closed vat and the air above is vacuumed out,