SALT part 2: “The History of Salt Production in the S.F. Bay”

(See  SALT part 1: The Newark Museum of Salt)  

“The History of Salt Production in the S.F. Bay” is a small exhibit about salt in the Bay on the 2nd floor of the Fremont Main Library. There are photos and artifacts, a big chunk of salt crystal included, provided by Cargill. The exhibit will be there until the end of September.

On Monday, September 24th, there was a talk at the Fremont Library by a Cargill representative with the Washington Township Historical Society present.

You could learn some historical facts:

Captain John Johnston, ‘a failed 49er’, started the first commercial salt works on the Bay in 1854.  Several family owned salt works sprung up, especially after the Comstock Lode find when salt was used to extract silver. Leslie Salt refining Co. started in 1901 and then successively bought out a number of salts works through the years.

The salt was sold and used in paper pulping, for livestock and in food preservation.

Cargill purchased Leslie Salt in 1978. The peak of salt production was in 1994 with 40,000 acres and operations in Napa, Redwood City and Newark.

The Newark plant is the only solar (using evaporation of salt water) salt producer in the US, currently producing 500 000 tons of salt per year with 200 employees.

Some facts about salt production:

Originally the salt was harvested with picks and shovels and using mules and carts for transport. In 1936 Leslie Salt developed a mechanical harvester, and there were tracks laid out and moved where the carts went.

At one point there were windmills and ‘Archimedes screw’ technique to pump the water into higher ponds.

It takes about 4.5 years to go from salt water to harvesting of the salt. The salt is led into progressively saltier ponds until it reaches saturation, going from 2.5 % salt to 25% ’pickle’. At the saltier levels, only brine shrimp and algae can handle it. The higher the salt content, the redder the color of the pond. When it turns crimson it is ready.

Originally the salt was scraped of the clay bottom of the bay, but that resulted in a harvest with clay remains and other undesirable contaminants. Today the salt is grown in layers of 6 inch and you leave the bottom layers alone to get a purer harvest. There are also ‘crystalizer beds’ with retaining walls.

When a dam is opened you can see the water rush out, as at the Don Edward location. This stirs up the bottom of the canals and ponds and is greatly appreciated by the birds who feed on the plankton and shrimp that become accessible. This is when you can be treated to the sight of hundreds of pelicans next to Coyote Hills.

When it is time for harvest it is a 24/7 operation. You don’t want the winter rains to dilute the salt.

After harvest the salt is put on the ‘Stack’, the 90-foot salt hill that is a Newark landmark.

The salt is refined, washed and recrystallized several times before it goes to Morton’s Salt next door and is sold as table salt.

Cargill has chosen not to try to market any ‘fancy’ version of sea salt even though restaurants are now into NaCl (salt) in more expensive versions. The Cargill salt brand is ‘Diamond Crystal’. (You can read about ‘fancy’ salt in this NPR blog: http://www.npr.org/blogs/thesalt/2012/09/20/161498088/three-burning-ques...)

Bittern is a by-product after the sodium chloride (salt) is purified. It consists of magnesium chlorides, sulfates and other chemical compounds. It is sold off as dust control for construction sites and vineyards.

Cargill and the Bay

The Cargill representative stressed several times Cargill’s role as a ’preserver’ of the Bay and their generous land donations.

Part of the Cargill Empire became the Don Edwards San Francisco Bay National Wildlife Refuge in 1979.

In 2003 the State of California negotiated a Plan for the Bay and acquired more acres for restoration and Cargill got 100 million dollars. According to the deal with the State, Cargill has the right to keep their salt production in Newark (with 9,700 acres within the refuge) in perpetuity.

Other salty questions at the Monday talk:

Why doesn’t the salt hill melt in the rain?

-       The salt has a hard crust and the water will just run off.

How much money does the Newark plant make?

-       Not disclosed, since Cargill is privately owned.

How will global warming and sea level rise affect the ponds?

-       No problem, they will just raise the levees. The point was brought up that             the ponds and levees are protecting the communities around the Bay.

Why are there no tours or outreach to schools?

         ‘Corporate America’ doesn’t allow it. It is possible for Cargill to visit schools,          but the schools have to take the initiative to approach them.