Salt, along with flour, water, and yeast, is one of the fundamental components in the process of baking, and therefore, it plays essential roles in this process. The salt used in baking is the same as the one we use at home, and chemically, it is sodium chloride. In recent years, there has been increased sensitivity on the part of various governments and international organizations to the need to reduce the amount of sodium in our diet, as it leads to higher blood pressure and an increased risk of cardiovascular diseases. It is the sodium present in salt that causes these negative health effects. For this reason, there has been a growing interest in reducing or eliminating the amount of salt used in baking processes.

One aspect you can find in various books discussing salt is its origin, which can be either sea salt (obtained through water evaporation) or mined salt. However, the origin of salt does not affect its functionality in baking processes since salt has a high purity of sodium chloride, and the percentage added to the dough is quite low. There have been attempts to promote or sell the idea of incorporating iodized salt (with a small percentage of iodine) for potential nutritional benefits, but these attempts have not been very successful. This iodized salt is produced artificially by adding iodine to regular salt.

Another important aspect of salt is its particle size. In trade, salt is typically categorized as fine salt or coarse salt. In this regard, what’s important about salt is its ability to dissolve well in the dough, which is better achieved with fine salt. Coarse salt can be used for some types of product decoration or finishing on the surface, as in pretzel, but it is not advisable to incorporate it into the dough, as it does not completely dissolve in the processes.

Effects of salt on bread

The most important aspect of using salt in baking is understanding how it influences the processing and the final product. Below are the most significant effects on the dough and bread:

Salt increases the strength of the dough. This increase is due to interactions with the proteins that form the gluten network, making the dough slightly more elastic and less sticky. This effect may also extend the necessary kneading time, but it is usually not very noticeable.

Salt prevents the whitening of the crumb. The pigments responsible for the cream colour of the crumb can oxidize in the presence of oxygen, which happens during kneading. When they oxidize, these pigments lose their colour, making the dough and crumb appear whiter. Salt has antioxidant properties, preventing these oxidations and preserving these pigments. If a slightly whiter crumb is desired, salt can be added at the end of kneading, allowing some time for it to disperse evenly throughout the dough.

Salt results in slightly darker and less matte crusts due to its influence on Maillard reactions. These crusts are also somewhat crisper.

Salt slightly slows down fermentation. Yeast is sensitive to high osmotic pressures, and salt increases these pressures, making it more challenging for yeast to act. Fortunately, the salt content is not very high, and yeast, though slower, still works effectively. If faster fermentation is desired, you can opt to increase the yeast amount or the fermentation temperature, but the fermentation times are already optimized for these conditions.

Salt is a flavour enhancer. This is the most important and challenging-to-imitate effect of salt. Salt not only imparts a salty taste but also primes our taste buds to be more sensitive to and perceive other flavours more intensely. That’s why when salt is removed, the product is described as bland because the perceived flavour is significantly reduced.

It is also said that salt, being a hygroscopic product, helps the bread retain moisture better or even absorb moisture when the atmosphere is humid, but this effect is quite minimal. However, a lower microorganism development in long-lasting bread, such as sandwich bread, can be observed due to the reduced water activity caused by salt. In this case, eliminating salt will increase this microorganism development.

As a consequence of these functions, salt-free bread has much less flavour, a whiter crumb, and a paler, less crispy crust, provided that nothing is done to compensate for these effects.

In the case of using salt in sourdough, it also influences the regulation of the microbiota, which will be different if no salt is used, or the salt content is reduced.

Salt content in bread

Changes in the bread-making process since the early 20th century, such as mechanized kneading, reduced fermentation times, or lower use of sourdough, have reduced the flavour of bread. To compensate for this, bakers have gradually increased the amount of salt in bread. Until a few years ago, it was common to use 2% salt based on flour weight, compared to values close to 1% that were used previously. However, the health problems of the population, including increased hypertension and cardiovascular issues, have led many countries’ governments to legislate to reduce salt consumption. In Spain, as part of the NAOS strategy, agreements have been reached to gradually reduce the salt content in bread. The new Quality Standard for Bread sets a maximum of 1.31 grams of salt per 100 grams of bread when analysed using chloride determination or 1.66 grams of salt per 100 grams of bread when analysed using total sodium determination. However, this requirement will only take effect from April 2022. The idea is to gradually reduce the salt content so that consumers get used to it and do not perceive it as negatively affecting bread quality, as has been happening in recent years. This new regulation also includes salt-free bread under the common bread category, which has a direct effect on taxes (VAT) imposed on this product, as they are lower than those for special breads.

If you want to significantly reduce the salt content in bread, the most common solution is the use of potassium chloride. It is important to note that the negative component in salt is sodium, so replacing it with potassium eliminates this issue. Potassium chloride has very similar effects to sodium chloride in terms of its impact on dough strength, fermentation, and the colour and characteristics of crumb and crust. However, its effect on flavour is somewhat different and imparts unusual tastes that have been described as metallic or bitter. One possibility is to mix sodium chloride with potassium chloride to reduce sodium content without making this detrimental effect very noticeable, but it seems that this is only possible at a maximum percentage of 30-40%. There has also been research into the possibility of incorporating additional products to mask the unusual flavours of potassium chloride, such as flavour enhancers. Flavour enhancers include glutamate, which provides the well-known umami taste, typical in Asian cuisine, or some yeast extracts, but all of them introduce flavours into the bread that are different from the usual ones. These can be used either alone or in combination with potassium chloride to reduce sodium content. Another highly interesting alternative is to enhance the flavours produced by fermentation by using sourdough and slower fermentations. This way, more flavouring and aromatic compounds are generated, reducing the need to enhance flavours artificially. The effects of salt on dough strength are easier to achieve by reducing the water amount in the formulas or using stronger flours or reinforcing additives.

In general, salt-free bread tends to be very bland, and its sales are quite limited, although they have increased in recent years due to the growing number of people advised by doctors to reduce sodium intake as much as possible. These breads are primarily sold to this group, but efforts should be made to improve their sensory quality.

Further information

Avramenko, N.A., Tyler, R.T., Scanlon, M.G., Hucl, P., Nickerson, M.T. (2018) The chemistry of bread making: The role of salt to ensure optimal functionality of its constituents. Food Reviews International, 34:204-225.

Belz, M.C.E., Ryan, L.A.M., Arendt, E.K. (2012) The impact of salt reduction in bread: A review. Critical Reviews in Food Science and Nutrition, 52:514-524.

Quilez, J., Salas-Salvado, J. (2012) Salt in bread in Europe: potential benefits of reduction. Nutrition Reviews, 70:666-678.

Silow, C., Axel, C., Zannini, E., Arendt, E.K. (2016) Current status of salt reduction in bread and bakery products – A review. Journal of Cereal Science, 72:135-145.