Commercially, pectin is extracted by treating the raw material
with hot dilute mineral acid at pH about 2. The precise length of
extraction time varies with raw material, the type of pectin desired,
and from one manufacturer to another. The hot pectin extract is
separated from the solid residue as efficiently as possible. This is
not easy since the solids are by now soft and the liquid phase are
viscous. The viscosity increases with pectin concentration and
molecular weight.