Salt extraction II

June 11, 2010

As I returned to the iron cauldron, I noted that it had been carried outside during the weekend, possibly due to the rather unsightly appearance of the solidified salt. However, due to the rather unfriendly weather here, the cauldron still contained some water. As I had realised that the salt was somewhat corrosive to the metal in the iron cauldron I chose to move it to the more durable soapstone vessel. Though the water reduced quite well in the stone vessel, it was perhaps not an optimal method, a preferred approach would have been to use a rather open vessel in which small amounts of brine are added and boiled away.

Second boiling of salt

The finsihed salt

The salt broken up and grainy

The resulting salt was rather grey, coarse and never entirely void of water. In order to be able to weigh it I should have tried to cook it until it all was solid or hang it up to dry above the fire.

One Response to “Salt extraction II”

  1. If you try boiling salt completely dry inside a metal vessel (or any impermeable vessel)you will usually have that problem to evaporate the last bit of water.
    You need more time and more heat, because the layer of salt forming at the bottom and on the walls of the vessel acts like some kind of insulation. Unglazed ceramic vessels made of coarse and rather porous clay (so-called “briquetage vessels”) will have residual humidity evaporate through the vessel walls.
    If you use an iron vessel, best take one that is rather flat and with a wide opening, like a pan or a chinese wok. Take the salt out while it is still a bit wet and let it dry out on a board or inside a basket near the fireplace. Saves time and energy. The wet salt can be greyish in colour but usually gets whiter while drying.
    I have some pictures of salt making experiments with different kinds of boiling vessels at my flickr account:
    http://www.flickr.com/photos/27593333@N05/

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