Fondue science

The cheese fondue seems to be so simple to make — mix wine, cheese, starch powder and spices, warm it up, stir and eat. But the science is actually much more complex.

The dish is really a complex multiphase system caused by the rheology of the cheese, wine and starches, which can make all the difference between a creamy meal and a goopy mess of separated ingredients. At its most basic, a cheese fondue is water with a dispersed mixture of fat droplets, caseins and starch granules with the concentration and quality of the latter being of particular importance.

Scientists at the Institute of Food Nutrition and Health in Zurich investigated how to make a perfect fondue with the right texture, flavour, mouthfeel, viscosity and bread clinginess.

The perfect fondue must be able to coat the bread, defy gravity, give the right feel in the mouth and release its flavour without being too thick or too watery. In addition, the ingredients need to integrate with one another so the fondue doesn't curdle or separate.

Essentially, the cheese that goes into the fondue is a protein gel that encases globules of fat. As the cheese melts, the gel network shrinks and collapses, releasing the fats. Adding wine to make up 30–40% of the weight, especially if it's dry with a low pH, introduces both water and ethanol into the cheese, dispersing the proteins and emulsifying the fat globules. By adding a starch made from potatoes, maize or carrageenan amounting to 3% of total weight prevents the proteins, water and fats from separating. As it gelatinises, the starch also increases the viscosity.

The tricky bit is to get the fondue to settle around the gel point. That is, the point where the viscosity is set to make a sudden change from liquid to solid. By balancing the various electrostatic forces of the ingredients, the right level of viscosity can be achieved.

What this boils down to in the caquelon is that by carefully balancing the ingredients, especially the wine, and using the most efficient starch, like carrageenan, it's possible to make a cheese fondue with just the right creaminess, and it even makes it more digestible.

Ah — finally an excuse to use that fondue set that’s been hanging around for decades.

The research has been published in ACS Omega.

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