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Salt, Part 5: The Salts of Our Lives

Salt gets to our table in different ways and forms.  If you do much cooking, or pay attention to such things, you’ll have noticed that there are different forms of salt used in the kitchen, each with a specific role in coaxing food into a final state.  Crystal size is the primary differentiator between the salts we use for cooking, but the amount and type of impurities present also varies between salts.  Crystal size is determined by a combination of the concentration of the brine, the temperature and pressure of the evaporation process and the method of collecting the crystals.  Impurities may either be naturally present, added during processing, or be completely removed.

Table salt – This is the salt that we know and love. Small, uniform grains typically sold with iodine and anti-caking agents added.  Iodine has been added to table salt since a government initiative in 1924 to eliminate thyroid goiter from the population by providing a sure-fire source of iodine in everyone’s diet.  Today, thanks to the huge amount of salt used in canned goods found at the grocery, goiter not likely to cause visits to the doctor in the US.  Not so true outside of the US.

Kosher salt – Kosher salt is prepared and inspected in conformance with kosher food preparation rules, has no additives, and consists of large, light flakes of salt that are much less dense than traditional table salt.  Kosher salt is a joy to cook with since it is easy to sprinkle onto foods with great control.  The large grains allow the fingers to grip and release specific amounts of the salt.  Normal table salt grains act almost like a fluid between your fingers making it virtually impossible to precisely sprinkle salt onto foods. Counter-intuitively, Kosher salt dissolves more quickly that table salt, since the surface area of Kosher salt is quite large compared to table salt.  And, since Kosher salt is less dense that table salt, more grains of Kosher salt are needed to achieve the same saltiness as table salt – another level of control for cook!  As a general rule, because of the smaller grain size, a volume of table salt could have twice the amount of salt as the same volume of Kosher salt.  Sadly, the grain size of different brands of kosher salt vary, so if exact amounts are important, weigh out the salt and don’t rely on volumetric measurement methods.

Sea salt – Sea salt is scooped up after a body of salty water has evaporated or from the surface or bottom of a sea brine as it evaporates and forms crystals.  The flavor of sea salt varies depending on the type of other minerals and impurities that co-exist with the salt in the brine before evaporation.  Sea salt from specific regions is often sold as a specialty salt, such as Fleur de Sel, harvested from contemporary salt basins in the Brittany region of France, and pink sea salt which comes from ancient seas in the Himalayans.

Rock salt – Rock salt, or underground salt, is found throughout the world.  Interestingly, one of the largest deposits is located in Michigan, essentially beneath the city of Detroit!  Rock salt with impurities is generally sold for industrial use and for salting roadways.  Rock salt that has been reduced to brine and then re-crystallized is sold as table and kosher salt.

Pickling salt – A fine-grained table salt that contains no iodine or other agents.  It turns out that the additives found in common table salt cause unwanted color changes in pickled foods and can cause the pickling brine to turn cloudy.  A special version of salt just for pickling is the answer.

Popcorn and Seasoned salt – Table salt that has extremely fine crystals, approximating a powder, is sold as popcorn salt and is used primarily to season its namesake, popcorn.  The same salt also finds use in rubs and combined with other seasonings to make, not surprisingly, Seasoned salt.

Black salt – This strange seasoning comes from India and its unique flavor comes from the iron, sulphur and other minerals that are present with the salt.  It sometimes makes an unwanted appearance in that fine dish of Indian food you just ordered.  Some people like it I guess…

– Chris

Salt, Part 3: Between Salt and a Hard Place

Halite, the pure mineral form of salt, is the only rock that we routinely consume as part of our normal diet.  Unlike most foods we eat, salt doesn’t burn and doesn’t catch fire.  For all practical concerns in the kitchen, it won’t melt or boil either. In fact, you would have to heat your oven to over 1,400 degrees Fahrenheit to get salt close to its melting point!  And you would need more than another 1,000 degrees to get it to boil, at which point your pans would start to melt!

Like other minerals, halite or salt is created through geological processes.  Volcanoes spew thousands of compounds into the atmosphere, all under various forms of pressure, temperature and in different concentrations.  When exposed to water and other forms of erosion over millennia, elemental forms of sodium and chlorine are dissolved and have the opportunity to combine and form salt.  Eventually salt concentrates in sea basins where it is trapped and left as a deposit when the water evaporates.  This salt can be collected directly and is called sea salt.  Salt left in the basin of prehistoric seas and covered by sediment becomes a deposit of salt deep underground.  The weight of the soil that accumulates on top of the salt deposit forces the edges of the salt deposit downward, pushing sediment underneath and towards the center of the deposit, creating a salt “dome” deep under the surface of the earth.  These domes tend to be geologically stable and are often found harboring deposits of oil, or are exploited for underground storage of nuclear waste (hmmmm).  The salt from these underground deposits can be mined using traditional underground mining techniques utilizing shafts that lead to underground rooms supported by pillars of the surrounding salt or rock.  Alternatively, water can be injected into a salt deposit, and the brine that bubbles back to the surface can be collected and processed.

– Chris

Molecular Gastronomy

The latest issue of Wired arrived and what do you know, another food scientist is hard at work! Hervé This (yep, that’s his name) is generating formulas that describe the structure of food in terms of basic proteins, carbohydrates, etc. The idea is that you can construct existing dishes, as well has thousands of never-before created dishes simply by plugging ingredients into a generically descriptive formula. He’s written a book and I’ll send you an update and a recipe (I mean, a formula) after I give it a read!

– Chris