The Secrets of Salt – How Is It Produced, and Why Is It Important for Shabbat Observers?

After exploring sugar and its hidden secrets, what could be sweeter than reporting on the familiar and seasoned salt, which also hides white secrets and several interesting components. It's worth providing some background and information on how salt is produced, though this might get lengthy and require continuation next time...

Worldwide, there are three main methods for salt production, but in our country, the most common is the solar method, which utilizes the sun's energy – simply put, evaporating seawater using sunlight. It's worth mentioning that salt is not extracted from the Dead Sea at all, despite Dead Sea water containing approximately 38 percent salt. This is because Dead Sea water also contains chlorine manganese and magnesium, making it bitter and oily to touch, with salt that's neither tasty nor particularly healthy. The main salt industry extracting from Dead Sea water at the factory in Kalya is used for other industrial purposes, such as leather processing. However, Dead Sea Works has recently begun to produce salt as well, but that's a somewhat different story that, Hashem willing, we'll discuss in the future.

This method was already mentioned in the Gemara (Tractate Shabbat - page 73b), "One who gathers salt from salt pans" - "who draws water from the sea into them, and the sun burns them, and they become salt" (Rashi). By the way, those who produce edible salt in our country using the simplest natural evaporation method are the "Salt of the Earth" factories located in Eilat and Atlit. In Eilat, most production occurs year-round from the Red Sea, while at the older factory in Atlit, built by Baron Rothschild, salt is extracted from the Mediterranean Sea – though there, salt is only produced during hot days when there is no rainfall that would prevent operations.

(Photo: shutterstock)

This salt production method raises an interesting halachic question, even before discussing the other additives in salt. If we try to summarize the production process, it works like this:

Seawater is drawn from areas where the water is quite deep and therefore relatively clean. From there, it flows naturally to evaporation pools, built in graduated heights between 40 cm and 20 cm. Initially, the salt percentage in the water is only about 4%, but as the water evaporates from heat and wind, and reaches a value of about 24% salt content, the water is channeled to several more pools where the salt begins to crystallize. These pools have drainage openings to allow water to exit before reaching a concentration of 28% salt, preventing magnesium in the water from settling on the salt and damaging it. Of course, we could elaborate on various simple and ingenious methods within this process. For instance, how important it is that seawater doesn't seep into the ground, even though this might seem like a convenient way to speed up seawater evaporation, but it reduces the salt level and causes the salt to absorb unwanted materials like gypsum and magnesium... Therefore, they utilize the pool height relative to sea level, as well as the nature of the clay soil in those locations. Besides various sealing methods for these pools, the technique of draining pool water back to the sea is also very interesting...

But if we approach the topic we're aiming for, we'll discover that after the seawater is drained and the salt is piled up, it's harvested monthly by harvesters (tractors) and trucks that bring the salt to the factory area. The salt is piled under the open sky in large, impressive mounds resembling snow mountains. After harvesting, the salt is washed with salt-saturated water (from recycled salt from the factory) to remove dust, gypsum, and sand that entered the pool with the wind, as well as the brine saturated with magnesium salts that remained on the collected salt. The washing is done in giant towers, with salt flowing downward and water flowing against it from above. After the salt is thoroughly washed and reaches a level of 98.5 percent sodium (salt), after all magnesium residues, sand, and gypsum are removed, the salt undergoes drying in a giant drum (centrifuge) reminiscent of a washing machine during the spin cycle. After the first wash, the salt undergoes another wash using the same technique, at which point the product reaches 99.8 percent sodium (salt) and becomes much whiter, then the salt is dried again. Up to this stage, there are no kashrut issues whatsoever.

But from here on, many kashrut and halachic issues arise. For example, after the second drying, the salt becomes truly dry, with all its moisture content totaling 3%, so if we touch it, it gives the feeling of dry salt. However, in this state, it's not suitable for packaging, and it will recrystallize, so it needs to be thoroughly dried. The drying is done via a conveyor that introduces the salt into a chamber with hot oil pipes at the entrance heated to 250 degrees Celsius. Next to the heating elements at the chamber entrance are air blowers that circulate hot air into the oven, causing the salt to reach a temperature of about 120 degrees Celsius. At the exit of that facility, there are also cold air blowers that cool the salt to fifty degrees Celsius.

(Photo: shutterstock)

This fact raises several questions. True, the salt is fit for consumption before drying and there's no concern of "bishul akum" (cooking by non-Jews), but on the other hand, how do we regard the drying? Is it considered fully cooked salt, since it contains some percentage of water that heats to a high temperature? If so, there's no prohibition to reheat it on Shabbat in a "kli rishon" (primary vessel). Or perhaps the minimal moisture only qualifies it as roasted, since the salt is heated when it's apparently very dry. And if it's considered roasted, how should those who follow Ashkenazi authorities handle it, who are concerned about the prohibition on Shabbat of recooking something already baked, "yesh bishul achar afiyah" (cooking after baking is prohibited)? Or perhaps it's not even considered cooked or baked, as the salt only undergoes drying in hot air, and anyone who has seen the process of how the salt rushes and flies inside the facility begins to be convinced that it's just drying and not even baking...

In conclusion, it's worth mentioning that this salt is not considered the refined salt that the authorities discussed, as its production is done differently, and its kashrut issues are completely different. The materials and concerns are also not similar to salt produced in Sodom.