Friends of Erre4m, welcome back to our blog. Today we continue our fascinating journey through the complex reactions that take place during the kneading stage. In our last post we put gluten under the magnifying glass. Today we talk about another hugely important ingredient… let's take a closer look!
Among the ingredients that play a fundamental role in bread dough, salt must not be forgotten. Its concentration is variable and depends on many factors; it is generally between 1.8–2.2% (this percentage is calculated on the total flour used) and in any case well below the concentrations considered harmful to the survival of the saccharomyces cells, as we saw in previous posts.
The slowing effect of salt on the fermentative activity of the yeasts can in practice be observed through a reduction in the volume of the dough combined with a finer crumb structure. The presence of coarse air cells in a dough, on the other hand, can be reduced by adding salt or by drastically shortening the bulk fermentation time.
It can therefore be stated that salt in a dough exerts an antiseptic action, both because it acts directly on the yeast and because of its action in slowing down the unwanted fermentations carried out mainly by bacteria.
For this reason, salt should not be added to fermented doughs such as bigas and poolish, unless one deliberately wants to slow down the maturing of the pre-ferments themselves in particular summer climate conditions. The same applies to natural yeast. It is very interesting to note in this regard that many industries deliberately add about 0.5% salt to natural yeast, for the sole purpose of obtaining a highly selected lactic microflora and limiting the presence of the so-called contaminants.
In addition to its antiseptic properties on micro-organisms, salt performs a hygroscopic action, that is, the ability to absorb water. When salt is added to the dough, in the minutes immediately following its addition, we can observe a greater compactness of the gluten, due to the drawing together of its meshes as a result of a greater number of bonds forming; the reduction in the tackiness and stickiness of the dough itself also becomes evident.
Generally, in most doughs, salt is added at the beginning of the second speed in order to bring about a better formation of gluten in the first minutes of this phase; moreover, thanks to its antioxidant properties, if added at the beginning it delays the oxidation of the doughs and produces a crumb with an ivory colour, whereas if added towards the end of kneading it produces an excessively white and glossy colour of the crumb due to the oxidation of the dough.
In particularly dry doughs, that is, with a water content of about 40–42% of the total flour, or in those doughs that must not undergo the mechanical heating caused by the action of the dough mixer and are therefore kneaded only at the first speed, it is added right at the beginning because, precisely on account of the reduced quantity of water, the latter would not dissolve and its crystals would be evident in the crumb of the finished product.
In addition to having a direct implication for the colouring of the crumb, it must be remembered that salt also acts directly on the colouring of the crust. A bread that contains salt shows a more pronounced crust colouring than a bread without it.
Lastly, it should be remembered that salt also acts on the preservation of the finished product precisely because of its microscopic properties. It very often happens that loaves produced at the same time, in the same environment, with the same processing and of the same size do not keep for the same length of time; the cause is to be sought mainly in the relative humidity of the environment in which the salted product is stored. In humid environments, the salt on the outside of the product absorbs part of the ambient humidity, making the product soft and thus limiting its preservation. The opposite situation occurs in dry environments.
To sum up, it can be said that salt has the following properties:
- Antiseptic and fermentation-slowing properties
- Antioxidant properties
- Hygroscopic properties, acting on both the dough and preservation
- Acts on the colouring of the crust and crumb
- Acts on preservation
- Acts on gluten formation
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Blog by Enrico Gumirato, pastry chef
