Gelatin solutions are produced through the process of rehydration, which reverses the steps used to create the dry gelatin powder (dehydration). The following steps are involved:

1. Swelling

2. Melting

3. Thinning

 

Swelling

Gelatin has the ability to absorb cold water. This phenomenon is referred to as "swelling" because the gelatin particles absorb the water and swell up. The time it takes for the particles to absorb a given volume of water depends on the particle size of the gelatin.

 

Melting

Well-swollen gelatin dissolves very easily and completely at a temperature of between 50 and 60 °C . However, when gelatin is subjected to heat or acidity, its properties change, resulting in a reduction of viscosity, loss of gelling power and an intensification of colour. The degree of these changes is a function of the temperature, acidity and time.

 

Thinning

Depending on the production technology used for a given foodstuff containing gelatin, it may be necessary to add the gelatin to the product either as a low- or a high-concentration solution. Thinning thus represents the process of adjusting the gelatin solution to the precise
concentration required.