The Salt Dilemma with Emmentaler Cheese

Emmentaler PDO has a low-to-very-low salt content compared to other varieties of cheese. Agroscope researchers show how this came about, what sort of effects this has on sensory quality, and what can be done about this.

Cheese salt content is closely associated with the sensory quality, ripening potential and food safety of the final product. Emmentaler PDO as well as other Emmentaler-type hard cheeses differ substantially from other cheese varieties in one aspect: they are often dry-ripened, and have a low-to-very-low salt content. Nowadays this low salt content is increasingly called into question as it has been proven to affect taste and flavour, and hence also the popularity of Emmentaler PDO.

This was not always the case. Over recent decades the NaCl content of Swiss Emmentaler PDO has fallen steadily, due to two major changes:

1. Labour-intensive dry-salting was abandoned from the 1970s onwards.
2. The 1990s onwards saw a rising awareness of low-sodium foods. The lower NaCl content in Emmentaler had the side-effect of making the cheese texture more supple. Furthermore, the introduction of a facultative heterofermentative lactobacillus culture rendered NaCl obsolete for controlling secondary fermentation.

In a model trial conducted at Agroscope’s research cheese dairy in Liebefeld, different salt-bath treatments were investigated with the aim of describing their influence on salt uptake: NaCl concentration (15 and 21 °Bé), temperature (11 and 16 °C) and duration in salt-bath (24 and 72h). These factors and combinations of them were tested with model Emmentaler and ‘Dolce’-type model cheese (scalding temperature, 52 °C; final stirring and moulding temperature, 49 °C;  Agroscope Transfer | No. 551 / 2024) using the propionic-acid-bacteria experimental culture Prop 23. A variant in which the cheese surface was dry-salted was also investigated.

Different salt-bath treatments can control salt content

A lower salt-bath concentration of 15 °Bé produced the benefit of a lower water loss without altering NaCl content. A longer salt-bath treatment (72 rather than 24h) and the dry-salting significantly increased the NaCl content of the cheese. High salt content in the cheese is associated with lower water content, altered ripening processes and altered propionic acid fermentation. In addition, it was shown that propionic acid fermentation requires a minimum NaCl content particularly so that the ratio of propionic to acetic acid remains optimally high in favour of propionic acid. This optimal NaCl content of around 9-11g/kg (0.9-1.1%) is far above the current average NaCl content of Emmentaler PDO of 3.5g/kg (0.35%). This also applies for the salt content of > 8g/kg, an essential minimum for a cheese not to be rated as insipid. Even if the NaCl content were increased within this optimal range Emmentaler PDO would still be considered a low-sodium food, and would thus still meet the aims of the Swiss Confederation’s salt strategy.

A higher salt content will alter product characteristics

A higher salt content also has implications for eye formation and organoleptic properties, however. More salt means fewer off-flavours such as bitterness, and a significantly more intense flavour. The characteristics of the curd are altered towards greater firmness which, in the case of excessive firmness, as occurs with dry-salting, negatively affects eye formation and edge thickness. The benefits outweigh the drawbacks, however: more and purer taste, a more intense flavour and less acetic acid, coupled with increased popularity. In future it will be important for practitioners to place due focus on the changes in curd consistency.