An emulsion is a dispersion of two non-miscible liquids, one of the majority and another that is in the form of drops in suspension. The smaller and more numerous the tears of the minor juice, the more they will interfere with the viscosity and mobility of the sauce. However, after a while, these sauces become unstable because liquids tend to join together to reduce the surface of exposure to the other liquid due to the surface tension they offer.
This behavior is verified by pouring two indissoluble liquids into the same container, such as water and oil: they are established in such a way that the contact surface between them is minimal. To overcome this situation, the cook needs to beat little by little, adding the more aqueous liquid to the more viscous one so that the thickness of the latter exerts pressure on the droplets of the other and transfers more braking force to the milkshake. For an emulsion to be stable, we will need another third component that has a part related to the most viscous liquid and another to the lightest to prevent the droplets from fusing. In any case, there are emulsions that we find spontaneously and naturally: milk, cream, or egg yolk. But there is also a wide variety of emulsified sauces that we use daily, such as the mayonnaise, the Dutch, the vinaigrettes, or the beurre blanc. In these cases, we play with a fatty part that is oil or butter, and another is the egg, white wine, vinegar, or lemon juice.
These sauces have three factors in common that differentiate them from the rest: a compact texture, a high viscosity and, what I consider more important, the liquids that provide flavor and aroma are distributed to the maximum, optimizing their contact with the taste buds, raising the said power.
We do not have to go far to remember an extraordinary experience with what is, for me, the excellence of emulsified sauces: the cod pil pil, with the power of our beloved extra virgin olive oil and the minerality and delicacy of fish