Salt Production & Sourcing

Salt Production & Sourcing

Salt is non-negotiable. Humans die without it. Food cannot be preserved without it. Livestock require it. Historically, salt was so valuable it served as currency (the word “salary” comes from salt). A community must secure a reliable salt source or trade for it — there is no substitute.

Why Salt Matters

An adult needs 3-8 grams of salt per day depending on climate and activity level. Heavy labor in hot weather can require 10-15 grams. But dietary needs are only part of the picture:

• Food preservation: meat curing uses 8 lbs of salt per 100 lbs of meat. Canning and pickling require salt. Cheese making requires salt.
• Livestock: cattle and horses need 1-2 oz daily, goats and sheep need 0.3-0.5 oz
• Hide tanning: 1 lb of salt per hide for preservation
• Chemical feedstock: salt is the precursor for lye (sodium hydroxide) used in soap making

For a community of 100 people with livestock, realistic annual salt consumption is 1,500-3,000 lbs (700-1,400 kg). This is a significant production or trade operation.

Seawater Salt

Solar Evaporation (Warm, Dry Climates)

The simplest method if you are near the ocean in a climate with strong sun and low rainfall.

Process:

1. Build evaporation ponds: shallow basins (4-8 inches deep, any width) with clay-sealed or lined bottoms. Located above high tide.
2. Fill with seawater: pump, bucket, or channel seawater into ponds
3. Wait: sun and wind evaporate water over days to weeks
4. Multi-stage: use 3-4 ponds in series. First pond is largest (initial evaporation). As brine concentrates, move to smaller ponds. This allows impurities (calcium sulfate) to precipitate out in early ponds.
5. Harvest: when final pond is saturated and crystals form on the bottom, rake them out
6. Dry and store

Yield: seawater is approximately 3.5% salt by weight. One ton (2,000 lbs) of seawater yields about 70 lbs of salt. To produce 2,000 lbs of salt per year, you need to evaporate roughly 28.5 tons of seawater.

Pond sizing: a pond 20×20 feet, 6 inches deep holds about 1,800 gallons (~15,000 lbs of seawater). In a sunny climate losing 1/4 inch of depth per day to evaporation, this pond empties in about 24 days, yielding roughly 525 lbs of salt. Four such ponds in rotation can produce community-scale quantities.

Boiling Method (Cloudy/Cold Climates)

Where solar evaporation is impractical:

1. Collect seawater in barrels
2. Boil in wide, shallow metal pans over wood fire
3. As water evaporates, add more seawater to keep the pan full
4. When brine is highly concentrated (thick, syrupy), reduce heat
5. Crystals form as remaining water evaporates
6. Scrape salt from pan, drain, dry

Fuel cost is enormous: boiling away 1 gallon of seawater requires roughly 8-10 lbs of dry wood. Producing 100 lbs of salt by boiling consumes approximately 3,000-4,000 lbs of firewood. This is why coastal salt was one of the most traded commodities in history.

Efficiency tips:

• Pre-concentrate brine by running seawater through salt-grass or straw bundles in the wind
• Use multiple pans in series, with waste heat from one warming the next
• Boil only on windy days (wind increases evaporation rate dramatically)

Inland Salt Sources

Salt Springs and Licks

Salt springs (brine springs) occur where groundwater passes through underground salt deposits. Indicators:

• Animal activity: deer, elk, and livestock will travel miles to salt licks. If wildlife congregates at a specific spot, check for salty water or soil.
• White mineral deposits on rocks or soil near springs
• Taste test: simply taste the water. Salty springs are unmistakable.

Salt springs produce brine at various concentrations — some very weak (1-2%), some nearly saturated (20%+). Concentrate weak brine by boiling, same method as seawater.

Brine Wells

If salt deposits are known to exist underground:

1. Drill or dig a well into the salt layer
2. Pump in fresh water
3. Water dissolves salt, creating brine
4. Pump brine to surface
5. Evaporate (solar or boiling) to recover salt

This requires knowledge of local geology. Ask elderly residents, check old geological surveys if available, or follow animal trails.

Rock Salt Mining

Surface or near-surface salt deposits can be mined directly:

• Identify exposed salt layers in cliff faces, road cuts, or cave walls
• Mine with pick and chisel
• Crush and dissolve in water, filter, re-crystallize for purification
• Or use directly if clean enough (rock salt for preservation does not need to be food-grade pure)

Purification

Crude salt from any source contains impurities: calcium sulfate (bitter), magnesium chloride (hygroscopic — absorbs moisture), sand, clay.

Simple Purification Process

1. Dissolve crude salt in the minimum amount of boiling water needed to dissolve it
2. Filter through clean cloth to remove insoluble impurities (sand, clay)
3. Let sit: calcium sulfate precipitates out of hot concentrated brine as it cools — pour off the brine carefully, leaving precipitate behind
4. Re-boil the filtered brine to evaporate water
5. Harvest crystals — the first crystals to form are the purest sodium chloride
6. Drain and dry

The bitter end: the last liquid remaining after most salt has crystallized is called bitterns — concentrated magnesium and calcium salts. Discard it (or use it to make tofu from soy milk — magnesium chloride is a traditional coagulant).

Iodine Deficiency

Natural salt contains no iodine. Without dietary iodine, the community will develop goiter and other thyroid disorders within 1-2 years.

Iodine sources to supplement diet:

• Seaweed (kelp, dulse, nori) — the richest natural source
• Ocean fish
• Dairy from animals grazing on iodine-rich soil
• If near the coast, periodically burn dried seaweed and mix the ash into salt supply

Storage

Salt is hygroscopic — it absorbs moisture from air and clumps.

• Store in sealed containers: clay crocks with lids, glass jars, sealed wooden barrels
• Keep in the driest location available
• Add a handful of dry rice or dry corn kernels to containers — they absorb ambient moisture
• Elevate containers off the ground (moisture wicks up through stone and earth floors)
• Salt does not spoil — it can be stored indefinitely if kept dry

Community Salt Budget

Use	Monthly Need (100 people)	Annual Need
Dietary (cooking + table)	40-60 lbs	500-700 lbs
Meat curing/preservation	20-40 lbs (seasonal peak in fall)	200-500 lbs
Cheese making	5-10 lbs	60-120 lbs
Livestock	15-25 lbs	180-300 lbs
Pickling/fermentation	5-15 lbs (seasonal)	50-150 lbs
Hide tanning	5-10 lbs	50-100 lbs
Total	90-160 lbs	1,040-1,870 lbs

Salt is one of the few resources worth long-distance trade expeditions. If your community cannot produce salt locally, establishing a trade relationship with a coastal or salt-spring community is a survival priority.