Fermentation Salt Calculator: Brine Percentage for Any Vegetable
1 kg green cabbage (sauerkraut), dry salt at 2%: 20 g salt (about 1 tbsp plus 3/8 tsp pickling salt), 3 to 4 weeks at 70 to 75°F (21 to 24°C).
Figures fermentation salt the way extension recipes write it: percent of the vegetable for dry salt, percent of the water for a brine.
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Your ferment
Fills in the usual method and percentage from the table below. Change either one if your recipe differs.
Trimmed and ready to pack. 0.1 to 50 kg (0.2 to 110 lb).
2 to 2.5% for sauerkraut and kimchi (Clemson, NCHFP). 1.5 to 10% accepted; the result flags anything under 2% or over 5%.
Pickling or canning salt is the extension recommendation. Anti-caking agents cloud the brine; Minnesota Extension says iodine can interfere with a ferment, though NCHFP says iodized table salt is safe to use. Grams are what count; the spoons are a check. Which salt do I have?
1 kg green cabbage (sauerkraut), dry salt at 2%
about 1 tbsp plus 3/8 tsp pickling salt
- Salt
- 2% of the vegetable weight; the cabbage makes its own brine
- Water
- none added
- Time
- 3 to 4 weeks at 70 to 75°F (21 to 24°C), NCHFP and Clemson
- Finish
- pH 4.6 or below, then refrigerate at 35 to 40°F (2 to 4°C)
Common ferments
1 kg cabbage for sauerkraut, 2% dry salt
20 g salt (about 1 tbsp plus 3/8 tsp pickling salt)
2% of the vegetable weight
3 to 4 weeks at 70 to 75°F
2 lb cucumbers in a 5% brine
35.5 g salt in 3 cups water
about 1 tbsp plus 2 7/8 tsp pickling salt, 5% of the water
1 to 4 weeks at 70 to 75°F
1 kg carrots in a 2.5% brine
18.8 g salt in 750 mL water
about 1 tbsp plus 1/8 tsp pickling salt, 2.5% of the water
5 to 10 days at 70 to 75°F
500 g hot peppers in a 3% brine
11.3 g salt in 375 mL water
about 1 7/8 tsp pickling salt, 3% of the water
5 to 10 days at 70 to 75°F
2 kg napa cabbage for kimchi, 2% dry salt
40 g salt (about 2 tbsp plus 5/8 tsp pickling salt)
2% of the vegetable weight
3 to 7 days at 70 to 75°F
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A fermentation salt calculator that works the way extension recipes are written: dry salt as a percentage of the vegetable (the sauerkraut brine ratio, 2 to 2.5% per Colorado State Extension, 2.25 to 2.5% per Clemson) or a brine as a percentage of the water (the hot sauce brine ratio, 3%; cucumbers 3.5 to 5%). Pick the vegetable, weigh it, and the calculator gives grams of salt, the spoon figure for the salt you actually own, how much water to mix, and the NCHFP time band for your room temperature.
Two conventions, stated every time. Dry salting has no added water, so the percentage is of the vegetable. A brine is salt dissolved in water before it meets the vegetables, so the percentage is of the water, the same convention as every other brine calculator on this site and as the extension recipes written per quart of water (Minnesota Extension: 1 to 3 tablespoons of salt per quart, about 2 to 6%). Some fermentation calculators divide by vegetables plus water instead; the result shows that jar-wide figure as a second line so recipes written either way can be compared.
dry salt: sodium chloride (g) = vegetable (g) x percent / 100
brine: sodium chloride (g) = water (g) x percent / 100 1 mL of water = 1 g
water (g), estimate = vegetable (g) x 0.75 editable
jar-wide percent = salt / (vegetable + water) shown for comparison
salt to weigh (g) = sodium chloride (g) / NaCl share of the salt you chose
spoons = salt to weigh (g) / g per tsp, tbsp, or cup of that salt
time = the vegetable's band at 70 to 75°F; x 1.5 at 60 to 69°F
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Salt weights
The spoon line comes from the density of the salt you picked, never from a fixed teaspoon weight. The old version of this page used 6 g per teaspoon for every salt, which is right for pickling salt and about double the truth for Diamond Crystal. Unrefined salts carry water and minerals, so the calculator works out the sodium chloride first and then weighs up: Celtic light grey is about 81% salt, so a 2% ferment of 1 kg of cabbage needs 24.7 g of it, not 20 g. The full table and its sources live on the salt conversion calculator.
| Salt | g per tsp | g per tbsp | g per cup | NaCl share | Source |
|---|---|---|---|---|---|
| Table or pickling salt | 6 | 18 | 288 | 100% | USDA FoodData Central, 6 g per teaspoon |
| Morton Coarse Kosher | 4.8 | 14.4 | 230 | 100% | Morton label, 1.2 g per 1/4 tsp |
| Diamond Crystal Kosher | 2.8 | 8.4 | 134 | 100% | Diamond Crystal label, 0.7 g per 1/4 tsp |
| Redmond Real Salt | 5.6 | 16.8 | 269 | 96% | Redmond label, 1.4 g and 530 mg sodium per 1/4 tsp |
| Celtic Sea Salt, light grey | 6 | 18 | 288 | 81% | Selina Naturally label, 1.5 g and 480 mg sodium per 1/4 tsp |
| Fine sea salt (approx.) | 6 | 18 | 288 | 100% | Treated as table salt (Morton chart 1:1) |
| Himalayan pink, fine (approx.) | 5.5 | 16.5 | 264 | 97% | Is Salt density chart |
| Himalayan pink, coarse (approx.) | 5 | 15 | 240 | 97% | Is Salt density chart |
| Maldon and other flake salts (approx.) | 2.8 | 8.3 | 133 | 100% | DadCooksDinner, 33.2 g per 1/4 cup |
Time and temperature
The time bands are the vegetable's usual range at 70 to 75°F (21 to 24°C), the range NCHFP gives for fermented pickles and sauerkraut. Clemson Extension's sauerkraut figures set the temperature rule: 3 to 4 weeks at 70 to 75°F, 5 to 6 weeks at 60 to 65°F, softening above 75°F, and NCHFP notes sauerkraut may not ferment below 60°F. The calculator applies the same 1.5x stretch to every vegetable in the cool band and adds a warning in the warm and cold bands rather than inventing a number.
| Room temperature | What happens | Source |
|---|---|---|
| 70 to 75°F (21 to 24°C) | Sauerkraut and fermented pickles in 3 to 4 weeks; quick brined vegetables in 5 to 14 days | NCHFP, Clemson HGIC |
| 60 to 65°F (16 to 18°C) | Sauerkraut in 5 to 6 weeks; other ferments about half again as long | Clemson HGIC |
| Above 75°F (24°C) | Faster, but kraut may become soft; above 78°F risks spoilage | Clemson HGIC, UMN Extension |
| Below 60°F (16°C) | May not ferment | NCHFP |
Salt percentage by vegetable
Dry salt rows are a percentage of the vegetable; brine rows are a percentage of the water. Times are at 70 to 75°F. Rows marked house range sit inside the Minnesota Extension brine range (1 to 3 tablespoons of salt per quart of water) and are the starting points this calculator loads; the sourced rows are quoted from the extension page named. Olives are not covered: they need a debittering step first, so follow the NCHFP or UC ANR olive guide instead.
| Vegetable | Method | Salt | Time at 70 to 75°F | Notes | Source |
|---|---|---|---|---|---|
| Classic pickles | |||||
| Cucumbers (dill pickles) | Brine | 3.5 to 5% | 1 to 4 weeks | Half-sour in a week, full-sour in 3 to 4 weeks; NCHFP uses 1/2 cup salt to 8 cups water | NCHFP |
| Cornichons | Brine | 3.5 to 5% | 5 to 10 days | Small cucumbers, quick ferment | House range |
| Cabbage family | |||||
| Green cabbage (sauerkraut) | Dry salt | 2 to 2.5% | 3 to 4 weeks | Clemson: 2.25 to 2.5%; 3 tbsp canning salt per 5 lb is about 2.4% | Clemson HGIC |
| Red or purple cabbage | Dry salt | 2 to 2.5% | 3 to 4 weeks | Same as green; slightly sweeter | Clemson HGIC |
| Napa cabbage (kimchi) | Dry salt | 2 to 2.5% | 3 to 7 days | Salt, wilt, then add the paste | House range |
| Brussels sprouts | Brine | 2.5 to 3% | 2 to 3 weeks | Halve or quarter for an even ferment | House range |
| Cauliflower | Brine | 2.5 to 3% | 7 to 14 days | Cut into florets | House range |
| Broccoli | Brine | 2.5 to 3% | 5 to 10 days | Include the stems | House range |
| Root vegetables | |||||
| Carrots | Brine | 2.5 to 3% | 5 to 10 days | Sticks or coins | House range |
| Beets | Brine | 2.5 to 3% | 7 to 14 days | Peel first; colors the brine | House range |
| Radishes | Brine | 2.5 to 3% | 3 to 7 days | Quick ferment, stays crunchy | House range |
| Daikon radish | Brine | 2.5 to 3% | 5 to 10 days | Sliced or in batons | House range |
| Turnips | Brine | 2.5 to 3% | 7 to 14 days | Pink with a slice of beet (Lebanese style) | House range |
| Ginger | Brine | 2.5 to 3.5% | 7 to 14 days | Slice thin; the heat mellows | House range |
| Peppers | |||||
| Jalapeños and other hot peppers | Brine | 3 to 3.5% | 5 to 10 days | Rings or whole; slit whole peppers | House range |
| Habaneros | Brine | 3 to 3.5% | 7 to 14 days | Hot sauce base | House range |
| Hot sauce mash | Dry salt | 3 to 5% | 1 to 3 weeks | Blend after fermenting | House range |
| Bell peppers | Brine | 2.5 to 3% | 5 to 10 days | Sweet and colorful | House range |
| Alliums | |||||
| Garlic cloves | Brine | 2.5 to 3.5% | 3 to 5 weeks | May turn blue; that is normal | House range |
| Garlic scapes | Brine | 2.5 to 3% | 7 to 14 days | Spring only | House range |
| Pearl onions | Brine | 2.5 to 3.5% | 5 to 10 days | Cocktail onions | House range |
| Ramps (wild leeks) | Brine | 2.5 to 3% | 7 to 14 days | Foraged in spring | House range |
| Beans, pods, and stalks | |||||
| Green beans (dilly beans) | Brine | 2.5 to 3% | 5 to 10 days | Trim the ends, pack upright | House range |
| Asparagus | Brine | 2.5 to 3% | 5 to 10 days | Trim the woody ends | House range |
| Okra | Brine | 3 to 3.5% | 5 to 10 days | Leave whole to limit slime | House range |
| Snap or snow peas | Brine | 2.5 to 3% | 3 to 7 days | Quick and crisp | House range |
| Tomatoes and fruit | |||||
| Green tomatoes | Brine | 2.5 to 3% | 7 to 14 days | Classic Southern pickle | House range |
| Cherry tomatoes | Brine | 2.5 to 3% | 5 to 10 days | Prick the skins so they do not burst | House range |
| Preserved lemons | Dry salt | 10% | 4 to 8 weeks | Salt cure, not a low-salt ferment; use the rind | House range |
| Watermelon rind | Brine | 2.5 to 3% | 5 to 10 days | Remove the green skin, keep the white | House range |
| Mushrooms | |||||
| Button or cremini mushrooms | Brine | 3 to 3.5% | 5 to 10 days | Whole or halved | House range |
| Shiitake | Brine | 3 to 3.5% | 7 to 14 days | Remove the stems | House range |
| Traditional | |||||
| Capers | Brine | 8% | 4 to 8 weeks | A salt cure; salt-packing also works | House range |
| Curtido (Salvadoran) | Dry salt | 2 to 2.5% | 1 to 3 days | Cabbage, carrot, onion | House range |
| Giardiniera (Italian) | Brine | 2.5 to 3% | 7 to 14 days | Mixed vegetables | House range |
| Tsukemono (Japanese) | Dry salt | 2.5 to 3% | 1 to 3 days | Quick pressed pickles | House range |
How lacto-fermentation works, and the safety rules
Lacto-fermentation is the souring of vegetables by the lactic acid bacteria that already live on them, with salt holding back the competition while they work.
Lactic acid bacteria (Leuconostoc first, then Lactobacillus) live on the vegetables already. Salt at 2% or more holds back the competition long enough for them to take over, and the acid they make drops the pH to 4.6 or below, where the bacteria that cause food poisoning cannot grow (NCHFP, Utah State Extension). Keeping everything under the brine keeps oxygen, and with it mold and kahm yeast, off the surface.
- Use at least 2% salt. Clemson Extension puts sauerkraut at 2.25 to 2.5% and NCHFP's 3 tablespoons per 5 lb is about 2.4%; under 2% risks soft or spoiled ferments, and NCHFP says not to cut back on the salt.
- Keep the vegetables submerged. Anything above the brine is exposed to oxygen and can grow mold. Use a weight.
- Check the pH. A finished ferment reads 4.6 or below, usually 3.4 to 4.0. Strips are enough for a jar; a meter is better for long storage.
- Refrigerate when it tastes right. 35 to 40°F (2 to 4°C) slows the ferment to a crawl and keeps it for months.
- Trust your senses. Fuzzy mold, a slimy texture, or a putrid smell means the batch goes out. A flat white film is kahm yeast: skim it and check the brine level.
- Use salt without anti-caking agents. Pickling or canning salt, kosher salt, or plain sea salt. NCHFP says iodized salt is safe in fermented pickles; Minnesota Extension prefers iodine-free.
What you'll need
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- Digital kitchen scale reading to 1 g. A 2% ferment of 1 kg of cabbage is 20 g of salt; a scale is the only way to hit it with any salt.
- Glass fermentation weights that fit your jar mouth, to keep everything under the brine.
- pH test strips (range 2.5 to 4.5) or a pocket pH meter, for the 4.6 check before long storage.
- Pickling or canning salt. Plain sodium chloride, 6 g per teaspoon, nothing that clouds the brine.
How this page is checked
This calculator was built by Cedrick Reese for BrineCalculators.com. The sauerkraut percentage, the temperature bands, and the softening threshold are quoted from Clemson HGIC's sauerkraut page and Minnesota Extension's fermentation page; the cucumber brine and the 3 to 4 week time come from the NCHFP fermented dill recipe; the pH 4.6 line and the do-not-cut-the-salt rule come from NCHFP's general fermenting page and Utah State Extension. The other vegetable rows are house starting points inside the Minnesota brine range and are labeled that way in the table. Salt densities and purities are the site's shared constants, sourced on the salt conversion calculator.
The preset tiles and the answer strip are generated from the same constants and vegetable table as the calculator, so they cannot disagree with it. When an extension page changes a figure, the row in the table and the constant in this page's script change together. If a figure here disagrees with the source named next to it, report it through the contact page.
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Frequently asked questions
What salt percentage should I use for lacto-fermentation?
2% of the vegetable weight for a dry-salted ferment like sauerkraut or kimchi, with 2 to 2.5% as the working band; Clemson Extension gives 2.25 to 2.5% for sauerkraut, and the NCHFP rule of 3 tablespoons of canning salt per 5 pounds of cabbage works out to about 2.4%. For vegetables fermented in a brine, 2.5 to 3.5% of the water covers most of them and cucumbers take 3.5 to 5%; the NCHFP fermented dill recipe, 1/2 cup of salt to 8 cups of water, is 7.6% of the water in a loosely packed crock. Do not go under 2%: NCHFP says not to cut back on the salt a fermented recipe calls for.
How do I know when my ferment is done?
Taste it. Sauerkraut is fully fermented when it tastes tart and the bubbling has stopped, 3 to 4 weeks at 70 to 75°F and 5 to 6 weeks at 60 to 65°F (Clemson Extension). Brined vegetables such as carrots or beans reach a pleasant sourness in 5 to 14 days and fermented cucumbers in 3 to 4 weeks for full-sour (NCHFP). A cloudy brine is normal. For a check you can measure, the pH should be 4.6 or below, and finished ferments usually land between 3.4 and 4.0.
What's the white film on top of my ferment? Is it safe?
A thin, flat, white or wrinkled film is kahm yeast. It is not dangerous but it can add an off flavor, so skim it off with a clean spoon, make sure everything is under the brine, and carry on. Fuzzy, raised spots in green, black, pink, or blue are mold; discard that batch. Kahm is flat and matte, mold is fuzzy and three-dimensional. When you cannot tell, throw it out.
Why are my fermented vegetables mushy instead of crunchy?
Too warm, too little salt, or too long. Clemson Extension says sauerkraut above 75°F may become soft, and Minnesota Extension flags spoilage risk above 78°F; keep the jar at 60 to 75°F, with 70 to 75°F the NCHFP working range. Salt under 2% lets the softening enzymes and the wrong bacteria get ahead. Move the jar to the fridge once it tastes right. For extra crunch use fresh, firm produce, trim the blossom end off cucumbers, and add a tannin source such as a grape, oak, or horseradish leaf.
Should I weigh my salt or measure by volume?
Weigh it. A tablespoon of pickling salt is 18 g, a tablespoon of Morton Coarse Kosher is 14.4 g, and a tablespoon of Diamond Crystal is 8.4 g (makers' labels), so a recipe written for one salt and scooped with another can be 50% off. The calculator gives grams first and the spoon figure for the salt you chose second. A scale that reads to 1 g is enough for a jar; to 0.1 g helps for small batches.
Can I use tap water for my brine?
Usually. Chlorinated tap water can slow a ferment; chloramine, which many cities now use, does not boil off. If your ferments are sluggish, use filtered or bottled spring water, or boil and cool the tap water (that removes chlorine but not chloramine). Do not use softened water, which trades calcium for sodium, and avoid water with a strong iron or sulfur taste.
How long do fermented vegetables last? Do I need to refrigerate them?
Yes. Once it tastes the way you want, move the jar to the refrigerator at 35 to 40°F (2 to 4°C), which slows the fermentation to a crawl. Kept submerged and cold, fermented vegetables hold for 4 to 6 months, and sauerkraut longer, though they keep getting a little more sour. Discard anything with fuzzy mold, a slimy texture, or a putrid smell. NCHFP also gives a canning process for sauerkraut and fermented pickles if you want shelf storage, at the cost of the live bacteria.
Why did my garlic turn blue or green during fermentation?
Sulfur compounds in garlic react with the acid the ferment makes, and with trace copper in the water, to form blue and green pigments. It is safe to eat and tastes the same. Young, fresh garlic is less likely to change than garlic that has been stored for months.
What's the difference between dry salting and brine fermentation?
Dry salting is for vegetables you shred or chop, such as cabbage for sauerkraut or kimchi: the salt, 2% of the vegetable weight, pulls out enough juice to cover the vegetables in their own brine. Brine fermentation is for whole or large pieces, such as cucumbers, carrots, and beans, that do not give up enough liquid: you dissolve salt in water at 2.5 to 5% of the water's weight and pour it over the vegetables. The calculator switches between the two, and each vegetable in the table is marked with its usual method.
My ferment isn't bubbling. Did something go wrong?
Probably not. Bubbling varies with the vegetable, the jar, and the temperature; below about 60°F (16°C) a ferment can stall, and NCHFP notes that sauerkraut may not ferment at all below 60°F, so move it to a spot in the 70 to 75°F range. Too much salt, above 5%, slows the bacteria down, and chloraminated water can too. Taste it after 5 to 7 days: if it is turning sour, it is fermenting whether or not you see bubbles.
Is the salt percentage based on the water or the whole jar?
On this page it depends on the method, and the result says which. Dry salt is a percentage of the vegetable weight, because there is no added water. Brine is a percentage of the water, the culinary convention every other brine calculator on this site uses (5% brine means 50 g of salt per liter of water). Some fermentation calculators divide the salt by vegetables plus water instead, which gives a lower-looking number for the same jar; the result panel shows that jar-wide figure too so you can compare recipes written either way.
References
- National Center for Home Food Preservation, fermented dill pickles
- National Center for Home Food Preservation, general information on fermenting
- Clemson University HGIC, making sauerkraut
- University of Minnesota Extension, fermentation
- Utah State University Extension, tips to safely ferment at home
- USDA Agricultural Research Service, the health benefits of fermented vegetables
- USDA Agricultural Marketing Service, bulk sauerkraut grades and standards
- USDA ARS, fermented and acidified vegetables (chapter 51)
- UC Agriculture and Natural Resources, sauerkraut guide
- University of Wisconsin, recommendations for safe production of fermented vegetables
- BC Centre for Disease Control, fermented vegetables guidance
Disclaimer
For educational purposes only: the information provided by this fermentation brine calculator and the accompanying content on BrineCalculators.com is intended for general educational and informational purposes only. It is not intended as, and should not be construed as, professional food safety advice, medical advice, or a substitute for consultation with qualified food safety professionals.
No guarantee of results: while we have made every effort to ensure the accuracy of the calculations and information presented, based on the NCHFP and university extension sources named on this page, we make no warranties or representations regarding the completeness, accuracy, reliability, or suitability of this information for any particular purpose. Fermentation outcomes vary with temperature, ingredient freshness, sanitation, and environmental conditions.
Food safety responsibility: the user assumes all responsibility for the safe handling, preparation, and consumption of fermented foods. Always practice proper food safety and sanitation when fermenting. When in doubt about the safety of a fermented product, discard it. Individuals with compromised immune systems, pregnant women, young children, and elderly individuals should consult a healthcare provider before consuming fermented foods.
pH testing recommended: for maximum safety assurance, use pH testing strips or a digital pH meter to verify that your fermented vegetables have reached a pH of 4.6 or below before consumption and storage.
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