inversion of emulsion may occur. This is undesirable because the inversion of an emulsion in this way
is usually accompanied by emulsion separation.
As the fat droplets become smaller and smaller, the mixture becomes more opaque. This is because
light cannot pass as easily through the small spaces between the smaller fat droplets as it could when
the droplets were larger with large spaces between them, so the emulsion becomes milky.
The are five main general reasons why emulsions may fail:
1. An emulsion may fail if the quantity of fat added to the water phase is insufficient – the
resulting emulsion will be too runny. In an emulsion containing too much water, the water
molecules will be able to flow much more easily than in an emulsion where the quantities of fat
and water are appropriate, and therefore will not possess the desired thickness and
creaminess of a perfectly balanced emulsion
2. If too much fat is added relative to the quantity of water, there will no longer be the sufficient
quantity of water needed for all the fat droplets to be stably dispersed, so the emulsion is likely
3. If the fat is added too quickly, the droplets are more likely to remain large and therefore
subsequently join up, so the emulsion is more likely to separate out.
4. Equally, if the emulsion is not whisked sufficiently while the fat is being added, the fat droplets
will remain large and are less likely to be well surrounded by the tensioactive molecules – they
are therefore more likely to join together and rise to the surface of the mixture, separating out
5. An emulsion may fail if the emulsion ingredients are too cold. At low temperatures fat droplets
tends to congeal. Congealed droplets are harder to disperse, so are less likely to be divided
into smaller droplets by the whisk action. They are therefore more likely to combine and rise
and separate from the liquid phase. Also, when warm, fat is more fluid, so can be more easily
dispersed in an emulsion. Vigorous whisking of an emulsion during its preparation is not