"Natural cloudy" apple juice is becoming increasingly popular due to its image of being natural and healthy.

The consumer expects that the trub in "natural cloudy" juices will remain in stable suspension, i.e. that the trub will not settle out of suspension. Various physical parameters are responsible for the stability of these trub particles in suspension:

Particle size Particle density Viscosity of the serum Particle shape and Particle charge

With the decanter juice, the adjustable fine dispersion facility means that 60% of the particles are smaller than 1 m; this is the case with only 20% of particles with the press.

The major factor in the production of "natural cloudy" juices is rapid processing. Juicing must be followed immediately by pasteurisation in order to inactivate the enzymes in the apple.

The yield values (single-stage process) are between 70 and 83% (by weight), depending on the ripeness of the raw product and on the throughput capacity of the machine. The juice is of uniformly high quality and virtually starch-free. Various technical process parameters enable juices to be made with defined degrees of turbidity and colour pigmentations.

The extent of stable turbidity is higher than that possible with conventional pressing technology. On the other hand, viscosity is in the usual range of between 1.5 and 2 cStokes.

If a particularly viscous juice with values of more than 3 cStokes is to be produced, it is necessary to heat the mash to 45 to 50 °C.

In particular, clear juices with stable and not excessively intensive turbidity require the addition of ascorbic acid into the mash and subsequent centrifugation; the mash must not be allowed to stand, and air contact must be prevented as far as possible throughout the entire process.

Blanketing with inert gas may be used for the process line under certain circumstances.

These data indicate that approximately half the original turbidity will remain stable in suspension with both techniques. However, the turbidity intensity of decanter juice is three times greater than that of press juice.