Curing Olives: Which Salt to Use and Why It Matters

Pickling salt is convenient, but weight is what makes a salt measurement dependable. A customer’s failed batch and a simple American Olive Farmer kitchen test demonstrate why the salt specified for curing olives should be weighed—not casually converted into cups.

Start With the Weight, Not the Salt

UC Agriculture and Natural Resources recommends pickling salt—also called canning salt or pure salt—for the olive-curing methods in Publication 8267, Olives: Safe Methods for Home Pickling. Its recipes were developed using fine-grained pickling salt, which dissolves readily and contains no anti-caking agents to cloud the brine.

That does not mean pickling salt is the only salt that can be used.

UC notes that an equivalent quantity of regular table salt may be substituted when pickling salt is unavailable. Coarse salt and kosher salt may also be used, but because their density can vary substantially, UC instructs home curers to measure them by weight to obtain the equivalent quantity.

UC also specifically advises against sodium-reduced salt substitutes.

Same Weight, Nearly Twice the Volume

To see how much difference crystal structure could make, we weighed one pound of two commonly available salts using two different digital kitchen scales.

• Morton Pickling Salt: in our test, 1 pound occupied approximately 1.75 cups.
• Diamond Crystal Kosher Salt: in our test, 1 pound occupied approximately 3.5 cups.

The same weight of salt occupied nearly twice the volume.

These measurements are not intended to create two new cup-conversion formulas. They demonstrate why converting between salts by volume is unreliable. The point is not to find a better cup measure. It is to stop converting and use the specified weight.

A Real-World Example: When a Volume Substitution Failed

A first-time olive-curing customer contacted me after noticing troubling changes in a batch of olives: dark freckles on the skin, dull or brownish flesh, and eventually visible mold in some jars.

The customer had followed a widely used curing guide, but when we reconstructed the process we found an important measurement mismatch.

Diamond Crystal Kosher Salt had been substituted for pickling salt using a cup measurement. Because the kosher salt occupied far more volume per pound, that volume-for-volume substitution delivered substantially less salt than the method specified.

By the time we spoke, some jars showed visible mold. The batch was discarded.

Different Methods Use Different Brine Strengths

There is another important reason not to memorize a single salt-to-water formula: UC does not prescribe one universal brine strength for curing olives.

The amount of salt changes with the curing method, the stage of the process, the size and variety of the fruit, and whether the olives are being cured or preserved for longer storage.

Selected examples from Publication 8267 illustrate the range:

These examples illustrate variation within the UC publication; they are not stand-alone recipes. Read the complete instructions for the method you intend to use before beginning.

This is why I no longer recommend describing “one pound per gallon” as a universal olive-curing rule. It is correct in some UC methods and stages, but not in others.

The Floating Egg: A Traditional Measure of Brine

Customers from several olive-curing traditions tell me some version of the same story: “My grandmother never weighed the salt. She added handfuls until a fresh egg would float.”

The floating-egg test is not an exclusively Italian practice. Variations of it have been documented in olive-curing traditions elsewhere around the Mediterranean as well. The principle behind it is real: as salt dissolves in water, the solution becomes denser. At sufficient density, an egg begins to rise and float.

In a kitchen without a scale or salinity meter, a fresh egg offered an ingenious and immediate way to judge the brine. In practiced hands—often using the same olives, salt, vessels, and family method year after year—it became part of an inherited way of working.

The word fresh matters. As an egg ages, the air cell inside the shell enlarges and the egg becomes more buoyant. An older egg may therefore rise more readily and give a different impression of the brine’s strength.

Even a fresh egg, however, is not a calibrated salinity instrument. It cannot tell us that a brine contains the particular weight of salt specified by a tested curing method. And as the UC guide makes clear, different olive preparations call for different quantities of salt.

There is another reason I hesitate to reduce this traditional practice to the instruction “float an egg.” The grandmother who performed the test every season may have understood far more than the memorable rule itself records: which egg, which salt, which olives, which vessel, how the brine should look, and what the fruit should feel like as the cure progressed. Some of that tacit knowledge can disappear even while the shorthand survives from one generation to the next.

I would never dismiss the floating-egg method as foolish. It is part of the ingenuity and accumulated experience through which families cured olives long before inexpensive digital kitchen scales sat in our drawers.

A peer-reviewed study of traditional olive preparation in the eastern Mediterranean describes the practice of adding salt to water until a raw chicken egg floats. The paper, Early Production of Table Olives at a Mid-7th Millennium BP Submerged Site off the Carmel Coast (Israel), examines evidence of olive processing thousands of years ago.

USDA also explains why the word fresh matters when using an egg as a rough indicator: the air cell inside an egg enlarges with age, making an older egg increasingly buoyant.

Read Early Production of Table Olives at a Mid-7th Millennium BP Submerged Site off the Carmel Coast (Israel)
Read USDA guidance on egg quality and the air cell

Curing and Preserving Are Different Stages

The distinction became much clearer to me as I worked through Publication 8267 page by page.

Curing removes enough of the olive’s natural bitterness to make the fruit palatable. UC describes water, brine, dry-salt, and lye methods, each producing a different style of olive.

Preserving addresses what happens after curing when longer storage is desired. Depending upon the olive style, UC discusses concentrated brine, refrigeration, freezing, drying, and pressure canning.

The salt concentration appropriate to one stage should not simply be carried over to another. Follow the complete method rather than isolating one salt ratio from its context.

American Olive Farmer’s Practical Rules for Measuring Salt

• Choose a tested method first. Do not begin with a preferred salt ratio and build the cure around it.
• Follow the specified weight. If the method gives ounces or pounds, use a kitchen scale.
• Do not substitute salts cup for cup. Crystal shape and density can make equal volumes very different in weight.
• Pickling salt is the simplest default. UC’s recipes are based on fine-grained pickling salt, and it dissolves readily without anti-caking agents that may cloud the brine.
• Kosher or coarse salt can be used when weighed. Measure the equivalent weight called for in the method rather than trying to calculate a volume substitution.
• Do not use sodium-reduced salt substitutes.
• Mix the brine as directed. Dissolve the salt thoroughly and include vinegar or other ingredients wherever the tested method specifies them.
• Label your batch. Record the curing method, salt used, salt weight, and date so you can reconstruct the process later.
• Take spoilage seriously. UC advises that olives which become moldy, soft, or bad-smelling during curing or preserving should not be eaten or tasted.

Frequently Asked Questions

What kind of salt should I use to cure olives?

Pickling or canning salt is the simplest choice because UC ANR’s recipes are written around fine-grained pickling salt. An equivalent amount of regular table salt may be substituted. Coarse and kosher salts can also be used when the required amount is measured by weight.

Can I use Diamond Crystal or another kosher salt?

Yes, when the curing method’s required salt quantity is measured by weight. Do not substitute kosher salt cup for cup for pickling salt.

Is it ever acceptable to measure salt in cups?

UC provides both weights and cup equivalents for the fine-grained pickling salt used in its recipes. American Olive Farmer recommends using the stated weight whenever possible, and especially whenever you change salt type or brand.

How much salt do I need for one gallon of water?

There is no single answer. Publication 8267 uses different salt quantities for different olive styles, fruit sizes, curing stages, and preservation methods. Choose the method first and follow its complete specification.

Does iodized table salt make olives unsafe?

UC’s concern with regular table salt is that anti-caking agents may make the brine cloudy. Its publication allows an equivalent quantity of table salt when pickling salt is unavailable. For simplicity and predictable brine appearance, pickling or canning salt remains the easiest choice.

Can I use a reduced-sodium salt substitute?

No. UC ANR specifically advises against sodium-reduced salt substitutes in its olive-curing publication.

Can I use the floating-egg test instead of weighing salt?

The floating-egg test is a genuine traditional method for judging brine density, but it is not a substitute for the salt weight specified in a tested curing recipe. Egg buoyancy changes with age, and different olive methods require different brine strengths. When a tested method specifies a weight, use the weight.

What should I do if my olives become moldy, soft, or bad-smelling?

Do not eat or taste them. Consult UC ANR Publication 8267 and its guidance for spoiled or questionable olives.