In
chemistry, it describes the process in which a gel contracts on standing and exudes
liquid.
One example is the separation of whey in cheese-making.
In dentistry, if a hydrocolloid impression is left to stand in an environment without sufficient moisture after the impression is taken, the impression will shrink & distort after a period of time. This dimensional change makes the impression, and the resultant model, inaccurate. Hence it needs to be wrapped in damp tissue - OR the impression needs to be poured up in dental plaster immediately.