Recently various nigari made through different processes have appeared in Japan. Make sure you know what sort of processes there are and what the levels of concentration are before making a purchase.

The processes of making nigari

Nigari is made by drawing up and letting seawater evaporate by exposing it to sunlight and heat. When seawater or saltwater taken from a saltpan is allowed to evaporate, first of all calcium sulfate (also known as gypsum, which is used in cement and is known to cause kidney stones) begins to crystallize. Calcium sulfate thus needs to be removed.

When the seawater has been reduced down to less than 1/10th, sodium chloride begins to crystallize. Finally, small amounts of magnesium sulfate, magnesium chloride and potassium chloride begin to form crystals. However we don’t let the process go that far, because when sodium chloride crystallizes, the liquid at this point contains a large number of minerals such as magnesium chloride, magnesium sulfate and potassium chloride, and is in fact nigari. Nigari has a distinct bitter taste (the word “nigari” is related to the Japanese word for bitterness, “nigai”). In particular magnesium sulfate gives it the bitter taste.

In making nigari, crystals form in the following order:

• Calcium sulfate (gypsum)
• Sodium chloride
• Magnesium sulfate
• Magnesium chloride
• Potassium chloride

The different ways of making nigari

Sun dried (natural nigari)

Natural nigari taken from the time-honored process of making salt by putting seawater into a saltpan and letting it dry in the sun. Nigari made by this process still contains large amounts of magnesium sulfate and hence has a very bitter taste. Nigari produced by this process is almost all non-Japanese.

Kettle-boiled (natural nigari)

Natural nigari taken from the water on top of the sodium that crystallizes on the bottom when seawater is boiled down in a large kettle. Almost all the nigari in Japan is produced by this method.

Reverse Osmosis

A process used in the making of deep ocean water.

When changing seawater to freshwater the “reverse osmosis” filter is used. With this reverse osmosis filter all the mineral elements as well as the impurities contained in seawater are removed, making this close to pure fresh water. The nigari taken from the reverse osmosis filter is added to this pure water, making deep ocean water. In other words, nigari water.

But this nigari, made from the reverse osmosis filter, is condensed seawater and is extremely high in salt (sodium) content. Rather than call it nigari, isn’t this just concentrated sea water, or strong saline? Basically nigari ought to be a solution of condensed seawater with the sodium largely removed, so that the sodium content is 1/5th of the magnesium content. The companies using this type of nigari cannot get it in large amounts so almost all of them either dilute it with water or adjust it by adding powdered magnesium. The right balance of minerals is very important for natural nigari.

The Ion Exchange Dialysis Method (natural nigari)

The ion exchange filter consists of double-membrane filters (80,000 yen each), with each block having 250 filters, there being hundreds of such blocks. Here sand-filtered seawater is ionized with electrical current, removing only the minerals. At this point PCBs, dioxins, poisonous mineral arsenic, mercury, lead and other such substances are removed. Currently no other system is able to deal with PCBs or dioxins. Also, as the salt water from ion exchange dialysis processed seawater contains almost none of the strong bitter-tasting ion sulfates and the calcium and magnesium sulfates do not crystallize out the resulting liquid is easy to drink. Natural nigari made by this process is very high in mineral content, quality, safety and comes with a reasonable price. This nigari is Japanese made.

Others

Great deals of chemically synthesized nigaris have appeared due to the recent boom of nigari in Japan. There are substances used as coagulants for tofu with calcium chloride and magnesium chloride added, as well as calcium chloride from non-Japanese sources. Magnesium chloride dissolved in water is also being sold as nigari. This is not unrefined magnesium chloride of seawater but simply unrefined magnesium chloride. We don’t take particular issue with the sale of unrefined magnesium chloride, but it is an extremely important that real nigari has a good balance of minerals.

As nigari itself is a byproduct of the production of salt and hence not easily obtainable in large amounts, there are retailers who sell it diluted with water. Kameyamado’s nigari has a naturally high level of concentration and so should be consumed 3-5 drops at a time, rather than in spoonfuls. There are also dealers who sell unchanged seawater as nigari. Nigari should have roughly five parts magnesium chloride to one part sodium chloride yet there are some products with nearly three times as much sodium chloride as there is magnesium chloride.