Sauerkraut Salt Calculator

How the calculator works

The calculator scales one step from a tested recipe. The National Center for Home Food Preservation, the US reference for home preserving, tells you to work in batches: about 5 pounds of cabbage at a time, with 3 tablespoons of canning or pickling salt for each.

salt in tablespoons = cabbage in pounds / 5 x 3

A note on the two figures in the source

The same recipe states its salt in two places, and they do not match. The ingredient list gives 3/4 cup of salt for 25 pounds of cabbage, which is 12 tablespoons. The method adds 3 tablespoons to each 5 pounds, which comes to 15 tablespoons over the same 25 pounds.

This calculator follows the method, because that is the step you carry out, 5 pounds at a time. If you are making the full 25 pound recipe, read the source and decide which figure you are following before you start.

If you enter kilograms, the weight is converted to pounds first. One kilogram is 2.2 pounds and needs about 1 1/3 tablespoons of salt.

Worked example

You have two heads of cabbage that weigh 4 pounds together after trimming and coring.

1. 4 / 5 = 0.8 of a batch.
2. 0.8 x 3 = 2.4 tablespoons of salt.
3. That is 2 tablespoons plus a little over 1 teaspoon.

For 10 pounds: 10 / 5 x 3 = 6 tablespoons, which is 1/4 cup plus 2 tablespoons.

Weigh the cabbage, not the head

The ratio is based on the cabbage that goes into the crock. Outer leaves and the core are discarded, and they can be a good share of the weight you bought. Trim, quarter and core the cabbage, shred it, and then weigh it.

If you do not have a scale, buy cabbage by weight and allow for the trim. A scale is better. This is a recipe where the ratio matters.

The method in brief

The source gives the steps in full, and you should follow it. In outline:

1. Work with about 5 pounds of shredded cabbage at a time.
2. Add 3 tablespoons of salt and mix thoroughly.
3. Pack it firmly into the container until the salt draws out the juice.
4. Repeat with the next 5 pounds, until all the cabbage is in.
5. If the juice does not cover the cabbage, add the top-up brine.
6. Weight the cabbage so it stays under the liquid, and cover the container.

Then leave it alone. The same source says not to disturb the crock until normal fermentation is complete, which is when the bubbling stops.

Temperature and time

Where you keep the crock decides how long it takes and how it turns out. The figures from the source:

• 70 to 75 °F: fully fermented in about 3 to 4 weeks. This is the recommended range.
• 60 to 65 °F: fermentation may take 5 to 6 weeks.
• Below 60 °F: kraut may not ferment.
• Above 75 °F: kraut may become soft.

A cool room or basement in the low 70s is ideal. A warm kitchen in summer is not.

Top-up brine

Fresh, juicy cabbage usually makes enough liquid to cover itself. Older or drier cabbage sometimes does not. If the juice does not cover the cabbage, add boiled and cooled brine made with 1 1/2 tablespoons of salt per quart of water.

Boil the water with the salt, let it cool completely, and pour in only enough to cover. The calculator shows this ratio beside every result so you have it to hand.

Storing it

Once the kraut is fully fermented, it can be kept tightly covered in the refrigerator for several months. To store it on a shelf, it has to be canned. The source gives hot pack and raw pack instructions. Follow those exactly and do not improvise.

What this calculator does not do

It scales the salt for sauerkraut, using one tested recipe. It does not give salt levels for other ferments. Kimchi, fermented pickles and other vegetables each have their own tested recipes, with different salt levels and methods, and a ratio for cabbage should not be carried over to them.

Tips and common mistakes

Use the right salt. Canning or pickling salt is pure salt with no additives. Table salt often contains anti-caking agents and iodine, and flaky or coarse salts measure very differently by the tablespoon.

Measure level tablespoons. A heaped spoon can hold half as much again.

Mix the salt in thoroughly. Salt that sits in one layer leaves some cabbage oversalted and some unprotected.

Keep the cabbage under the liquid. Check that the weight is doing its job.

Use a food-safe container. The National Center for Home Food Preservation also publishes guidance on suitable containers, covers and weights for fermenting.