I harvest salt through evaporation of saltwater from the ocean. The amount of money I save is negligible because table salt is so cheap – much like making my own soap, the value is in the quality. Harvesting salt is laborious but when done well I am left with a beautiful crystalized salt with no anti-caking additives.

Tools

Large carboy or drum to collect ocean water

Dolly or wagon (for transportation to your vehicle)

Cheesecloth or towel

Large pot – non-stick or glass or ceramic (metal pots can become damaged from the concentrated saltwater. Be aware, this pot may become permanently encrusted with minerals; see notes below)

Heat-resistant glass dish

Instructions

Find a beach far from a city with no runoff or boats. Collect the ocean water into a large carboy or drum and secure it in your vehicle so the water won’t spill.

Pour the saltwater through the cheesecloth or towel to filter out the larger detritus and put the filtered saltwater into your pot. Heat the water and boil it down to about 1/3 of its original volume. Lower the heat to a gentle simmer. A white substance will appear – this is calcium. The amount of calcium that precipitates out will vary depending on your saltwater and the amount you started with; once I see calcium I simmer for 20 minutes more then put a kitchen towel or coffee filter into a colander, set the colander into my glass dish, and pour my saltwater through. Discard the calcium and take a moment to scrub your pot clean.

Precipitation is when a solid is formed out of a solution, in this case by evaporating water and increasing the concentration of minerals until they crystalize. 

You can leave your glass dish out to evaporate on it’s own, or you can gently heat it using a hotplate. If using a hotplate, 130-150F is ideal.

Salt naturally forms crystals as the saltwater reaches saturation point. During evaporation, salt will form at the top of the water and stay afloat for some time as the crystals form an inverted pyramid structure, called hopper crystals.

If leaving your dish out It may take a few days for your solution to reach saturation. For either method, once saturation point has been reached your salt will begin to crystalize. Give the salt time to grow larger but don’t wait too long; magnesium will begin to precipitate as well, binding to the salt and giving it a bitter taste. (To correct this, dissolve the salt/magnesium crystals in water and leave to evaporate. When the salt crystalizes again, remove from the solution.) Some of your salt may fall to the bottom of your dish and some will remain floating at the surface. I use a spatula to scoop the crystals and use a fine mesh to drain them. After much of the water has drained away, set the salt on parchment paper to dry. You can also put your salt in the oven on the lowest setting to remove any additional moisture. Store as you would any salt.

Notes

Some additional minerals in ocean water are calcium, magnesium, sulfate, and potassium. These can crystallize and bind to your pot. I make sure to scrub any sediment away immediately after use.