Fermented Foods: Taking the Mystery Out Of Brine

The brine is the most important part of many fermented foods. Too little salt and the food will spoil. Too much and the food will be unpalatable, and may not even ferment. Despite this importance, the brine is often the most poorly described part of many recipes. Likewise, brines – or at least the salts used to make them – are a focal point of a lot of the mis-information surrounding fermented foods.

Because of its importance, I’m dedicating this entire post to making brine.

Dispelling the Salty Myth

If you read a lot of fermentation (or “health”) sites, you’d think that salt is some sort of magical substance. Exotic salts from distant locals are imbued with magical health properties, while the cheap stuff from the grocery store is a toxic mix of industrial chemicals. And strangely enough, many of the sites hyping those fancy salts often sell them…odd, isn’t it?

As you may suspect, those claims are bullshit.

You can use any form of table salt (sodium chloride) for fermenting foods, so long as it is from a food-safe source. So yes, you can use expensive pink Himalayan salt, or sea salt scraped from the sun-kissed skins of virgins sunning themselves on the beaches of an exotic Pacific island. But you can also use the cheapest table salt from Walmart. It doesn’t generally matter – in fact, the primary difference between fancy salts and cheap salts is the price – most of these salts unique colour are a result of trace minerals which, when used at normal levels in brine, are usually below a concentration you can taste or smell.

Salt Types

Three different ferments, three different brines (plus some wild yeast)

While most “fancy” salts won’t have a detectable impact on the flavour of your final food, there are exceptions. And these differences can be desired, or undesired. For example, the black sea salts from Hawaii get their colour from sulphur compounds. When used in foods these compounds impart rotten egg-like aromas and flavours which many find objectionable. In comparison, some sea-salts known for their intense sea-like flavour which can complement fermented foods such as kimchi. That said, most salts do not give perceptible differences in taste, given the relatively low level of the non-salt minerals found in them, and the other intense flavours common in fermented foods.

A claim commonly made about conventional salts is that they contain dangerous  – even deadly – additives. As is often the case with health claims,  are not fact based. These additives are added for two reasons:

  1. Anti-caking agents. Finely grained salts (i.e. standard table salts) are prone to sticking together into large masses. Anti-caking agents are often added in minute amounts (<0.1%) to these salts. Despite having some scary sounding names, these compounds are generally regarded as safe. Many are compounds that arte consumed by the microorganisms fermenting your food, or will breakdown shortly after being added to water. In other words, these compounds are not toxic, generally are broken down before you’d consume your fermented food, and some may even help feed your ferment.
  2. Iodation agents. By law, in many countries salt intended for general food/culinary purposes must be iodated. This is to prevent iodine deficiencies, which were common prior to the advent of iodated salt. These compounds are harmless – and indeed are good for your health. They are also present at levels well below where they may harm your ferment. That said, there is a reason to avoid them; the iodine in them reacts with starches in foods. This can stain the food an unpleasant-appearing purple/brown colour. This staining is harmless, but is not visually appealing.  Pickling, kosher and sea salts are non-iodated, If in doubt, check the box.

How Much Salt To Use

Your salt content is critical – you need enough to suppress the growth of unwanted organisms, but not so much that you suppress the growth of the bacteria that ferment the food. At the same time, you also want a concentration of salt that will complement the flavour and texture of the food. And if that’s not complicated enough, the amount of salt needed to protect from spoilage differs between foods. Some – like fermented peppers – are very susceptible to moulding and need high salt levels, while other foods (cabbage) can get away with a lot less.

Making matters worse, many recipes provide minimal guidance on the brine. They will state things like “I use a few tablespoons per cabbage”, while ignoring that “a few” is meaningless, you’ll get a lot less of a flaky salt into a tablespoon than a finely ground salt, and that cabbages vary greatly in size. Personal preferences also vary, so a recipe I appreciate may be overly salty to you. The advantage to using a known brine concentration is that you can reliably reproduce and adjust your recipes.

Generally speaking, brines range from 2% to 10%, with 2% representing a brine on the edge of not having a preservative effect and 10% suppressing most (but not all) fermenters. For comparison, sea water is about 3.5%.

It is best to prepare brines by weight of salt into volume (or weight) of water. At the bottom of the post you will find the table I use as a guideline in my own kitchen. The values in this table are based from my experiences and information I have gleaned from food safety research.

Generally speaking, brines over 10% do not allow fermentation to occur, and instead will preserve your food via the dehydrating effect of the salt. Foods preserved in this fashion often require soaking before consumption to reduce the salt levels to palatable levels. As your salt concentration increases, fermentation time also increases.

One last note, you can also prepare brines entirely by weight. Water weighs 1g/ml, so calculating brine additions is trivial. A 2% brine is 2g of salt into 100 g of water, 3.75% brine is 3.75g salt into 100 g of water.


The bulk of the brine is water, not salt, and yet the water rarely gets any discussion. You want to use water which tastes good, and which is free of any chlorine/chloramine . Removing chlorine/chloramine is less critical with fermented foods than it is with beer. However, removing/avoiding these compounds is cheap insurance against off-flavours and damaged fermentation.

If your municipality uses chlorine, you can simply measure out your water a day in advance, and leave it on the counter in an open container – the chlorine will evaporate out of the water, leaving chlorine-free water behind. A short boil achieves the same effect. If your municipality uses chloramine, it will not evaporate. You will either need to use a carbon filter to remove the chloramine, or you will need to purchase bottled water.

Lastly, make sure the water you use tastes good. It is not uncommon for well water (and even some municipal water) to have strong mineral characters. This will carry through to the foods you prepare, so if you don’t like the flavour of your water, you don’t want to use it to prepare fermented foods. You can purchase spring water from a  grocery store as an inexpensive replacement option, or filter your water through a brita-style filter system.

% SalinityGrams salt/cup water*Grams salt/litre waterRecommended Foods
2.5%6.2525Fruit, Sauerkraut**
3%7.530Fruit, Sauerkraut**
3.5%8.7535Sauerkraut**, Peppers
4%1040Peppers, Kimchi
4.5%11.2545Peppers, Kimchi
5%12.550Peppers, Kimchi
5.5%13.2555Kimchi, Cucumber Pickles
6-8%15-2060-80Cucumber Pickles
* 1 cup = 250 ml
** percent by weight, e.g. 3% = 3 g salt per 100 g cabbage

9 thoughts on “Fermented Foods: Taking the Mystery Out Of Brine

  • January 29, 2021 at 2:01 PM

    I’m curious to hear your thoughts on calculating brine percentage based on the weight of water plus the vegetable when determining salt percentage. It seems many of the fermenters I know are switching to this method rather than basing it solely on water content. This is how mash fermenters and sour kraut makers have been doing it when doing waterless ferments for ages and is recommended by the Noma book on fermenting. Also, not that it’s critical for lacto ferments, but your math isn’t exactly correct in your examples. A two percent brine is actually two grams of salt plus 98 grams of water.

    • January 29, 2021 at 2:13 PM

      If you are talking about brine percentage (which is what most recipes use), than weight salt per volume of water is what you want to calculate. Ad dinging the weight of the vegetables, without then decreasing the salt concentration, would lead to an overly-salted product. For example, if you made kosher pickles using 3% brine with 50% of the total weight of the pickles being brine, your effective brine concentration is actually 1.5%. If you calculated your salt weight based on the total weight, and didn’t account for that difference, you’d essentially end up adding a 6% brine to give a final 3% salt by weight ratio. Unfortunately, there is not a standard way that recipes report these calculations, so in my opinion, its best to be clear in your instructions on how salt ratios are calculated to avoid any confusion. Sadly, not all authors are as careful and sometimes it can be difficult to figure out how they calculated their salt addition.

      When it comes to “brineless” ferments like sauerkraut and pepper mashes, the only consistent way to calculate your salt addition is % salt by weight, as explained in my article.

      You are, however, incorrect about calculating salt additions to bring. By definition, % weight by volume is always calculated as grams of solute (e.g. salt) per 100 ml of water. What you have described is percent weight by weight, which is not how brine (or other liquid-solid solution) concentrations are calculated. Percent weight-by-weight is almost exclusively used for dry mixtures.

  • July 2, 2020 at 5:24 PM

    I have tried several times to make fermented green beans which my grandfather made when I was a kid, I can not get the recipe because both he and my grandmother have passed, I know they were done in a crock and took some time to make, do you have a recipe and instructions for making them?

    • July 3, 2020 at 4:09 PM

      I do not, but in theory a basic recipe should be simple. Make a brine that is 3.5% to 4% salt. Tightly pack beans into a jar, fill with the brine, and work out any air bubbles. Let sit in a cool-ish place until fermented. This would be a pretty basic/plain recipe, but you could easily add spices (garlic, dill, chillis, etc) to make it more flavourful.

      • January 29, 2021 at 2:49 PM

        I would think it would be overly salty as well, which is why I bought it up but is this not basically how mash fermenters calculate their salt content? 100 grams of peppers would get 3 grams of salt for a mash ferment at 3% but when calculated as brine for the same amount of peppers you may only use 50ml of brine to cover the peppers. I agree my example is not entirely correct as well, to be at a true 2% you would need to dissolve your 2 grams into a solution less than 100ml and then bring your water up to 100ml. Adding 2 grams of salt to 100ml would be slightly less than 2% as your finished volume will be greater than 100ml.

  • January 4, 2020 at 6:28 AM

    When calculating the concentration of brine is it a weight/weight percentage, or a volume/volume percentage? In your calculations you did a w/w calculation, but a lot of what I’ve seen online is measurements based on volume. Why this maters is when you do a v/v percentage such as “one tablespoon of salt per quart of water.” This will be twice the salt concentration, because the density of sodium chloride is 2.16 g/mL. So based on the example I provided you’d have a 1.6% solution if it is v/v, and you’d have a 3.2% solution if the measurement is w/w. I’ve even seen this inconsistency in books on fermentation.

    • January 4, 2020 at 2:34 PM

      I use both weight/volume and weight/weight in the article, as which one you want to use depends on the preparation method you are using.

      That said, if you use metric (as everyone should) weight/volume is the same as weight/weight, as 1 ml of water weighs 1 gram.

      When preparing a food fermented in a brine you should prepare the brine using weight/volume (e.g. grams of salt per ml of water).

      For ferments where the salt is added directly to the food, rather than via a brine (e.g. sauerkraut), you use weight/weight.


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