Make salt

Boil seawater or salty spring water down and down until white salt crystals are left in the pot.

takes patience⏳ two daystradition — not yet hand-tested

Salt is the key that unlocks most of keeping food. Rubbed on meat, it pulls the water out. Mixed into brine (salty water), it lets vegetables sour safely instead of rotting. Your body also needs a little salt every day to live, and food without any tastes flat and grey.

The sea is full of it. Every bucket of seawater is about one part salt in thirty. Boil the water away, and the salt cannot leave — it stays behind, white and dry, in the bottom of your pot.

You need

• Salty water. Seawater is the usual source. Inland, look for salt springs — water that tastes clearly salty — or salty pools where animals gather to lick the ground. Taste is your test: if the water tastes strongly of salt, it will make salt.
• Clean water, not harbour water. Take seawater from an open shore with waves, away from river mouths, camps, and anything dead or foul. What is in the water ends up in your salt.
• A wide clay pot — or several. Wide beats deep, because water leaves from the surface. This is why cooking in pots comes first.
• A cloth or tight basket to filter with — to strain out sand, weed, and small creatures before boiling.
• Lots of firewood — more than you think. Boiling water away takes long, steady heat. Gather a big pile first.
• Patience and a stick for stirring.

Steps

1. Collect the water at high tide from a clean, open stretch of shore. Fill every container you have — thirty measures of seawater give only about one measure of salt.
2. Let the water stand for a few hours so sand settles, then pour it through cloth or a tight basket into your pot, leaving the last gritty bit behind.
3. If the sun is strong, cheat first: leave the water in wide shallow containers in sun and wind for a day. The sun boils water away for free, and saltier water saves you firewood.
4. Set the pot over a steady fire and boil. Top the pot up with more filtered seawater as the level drops — this way one pot does the work of many.
5. Skim off any grey scum that rises. That is not your salt; your salt is dissolved and invisible.
6. Watch for the change. After hours of boiling, the water turns cloudy and white crystals begin to appear, like snow forming in the pot. Now the dangerous, easy-to-ruin part begins.
7. Lower the fire to gentle coals and stir often. Salt scorches and the pot cracks if you rush the end.
8. Stop while there is still a little wet sludge, not bone-dry. Scoop the wet salt out and spread it on cloth, bark, or a flat stone.
9. Let it dry in sun and wind for the rest of the day. Break up the lumps. You now have coarse white or greyish salt.
10. Store it bone-dry — in a pot with a lid, off the ground, away from rain and damp. Salt keeps forever if it stays dry; it only cakes into lumps when wet, and even then it is still good.

Watch out

• Dirty water makes dirty salt. Never use water from harbours, stagnant pools, or anywhere that smells bad. Everything bad in the water concentrates as it boils down.
• Burning the salt at the end. Strong fire on nearly-dry salt scorches it bitter and brown and can crack your pot. Finish slow, on coals, stirring.
• A bitter aftertaste in the very last liquid. The final spoonfuls of liquid that refuse to crystallise hold the sea's bitter salts. If your salt tastes bitter, pour that last liquid off before the final drying next time.
• Cracked pots. Clay pots hate sudden heat changes and hate boiling dry. Keep liquid in the pot until the very end, and warm pots gently.
• Running out of firewood halfway. Half-boiled brine left standing just waits for you, so no harm — but gather twice the wood you expect before you start.

How it works

Salt dissolves in water — it hides between the water, invisible. But when water is heated it leaves as steam, and salt is far too heavy to fly away with it. So every drop of steam that leaves makes the pot saltier, until the water left cannot hold all the salt anymore, and the salt is forced back into solid crystals before your eyes.