Table salt has been around for thousands of years. It was first used for preserving food during prehistoric times. In modern times, kosher salt comes in different varieties, each with its own particular properties.
Sea salt is basically salt produced by the evaporation off of seawater into the sea. It's frequently used as a seasoning in baking, cooking, photography, and even for preserving food. It's also known as mined gold, solar salt, or cave salt. Unlike mined ore, the production of sea salt continues to date from prehistoric times to the present. The majority of the world's table salt comes from these ancient deposits.
Some table salt is still produced from seawater, but much of it is "artificially" mined from impure pools or lakes. The bulk of the salt goes into the cans and boxes we use to store it. As mentioned, some of it evaporates, which creates a distinctive salty flavor. Today, most artificially mined salts are treated with iodine, calcium, magnesium, strontium and zinc, which improve the shelf life and taste.
Another big difference between table salt and sea salt is its texture. In addition to being harvested from seawater, sea salt is commonly harvested from the inland seas and lakes. Sea salt can be frozen or processed to create many different variations. In the case of table salt, however, the main differences usually lie in the mineral content. Each type will have different percentages of sodium and other minerals.
Salt has always been found in nature, so you can't really blame modern civilization for making table salt. It's hard to believe, but kosher salt was discovered long before the dawn of civilization. The Celtic people, who inhabited the British Isles between the sixth and fifth centuries B.C., used what was available around them as their main source of food and water. They harvested sea salt and used the fine rock crystal dust found in its crystals to cook food and drink.
In addition to its flavor, the ancient peoples of Britain and Ireland also noticed that sea salt had a unique texture. When they placed sea salt on wet grass, they found that it retained more of the original flavor than if they had simply put the salt on a dry surface. This led the early Greeks and Romans to develop an enormous table salt industry, based on using the mineralogy of the salt to make various items. Salt has always had a unique texture and there is no wonder why it has such a devoted following today.
The process of evaporation occurs when table salt is exposed to heat and/or moisture for any length of time. Evaporated water has zero negative ions and therefore will not add salt to the food or water you cook. The longer that an item is exposed to heat or moisture, the more negatively charged ions are produced and this results in less desirable results, such as a salty taste. Salt does need moisture to release its natural flavor, but no matter how long it is exposed to heat, the trace minerals like magnesium, potassium, calcium and sodium that are naturally present in sea salt will be left behind. These trace minerals add flavor and texture to foods, but evaporation is necessary to retain these essential trace minerals.
For those with high blood pressure, table salt is fine; however, a teaspoonful or less of sea salt should be avoided, especially in amounts greater than two tablespoons per day. In the case of hypertension, it is best to take measures to lower your blood pressure before consuming table salt. High blood pressure is much more common among those who have salt intake problems and the recommended remedy is to take medications that lower blood pressure and avoid salt in foods. If hypertension is in fact a problem for you, talk to your doctor about ways to help control it through healthy lifestyle choices.