Pressing fails: press cake blocks and no oil.

If the press cake blocks, the press pulp in the cap is rock-hard and you cannot turn the crank anymore: seed too dry! It should contain 10% moisture. On this page you can read how to determine the moisture content and how much water you should add to the seeds. Always wait 2 days before you use the seeds.

Characteristics of too dry seed

How do you notice that the seeds or nuts do not contain 10% moisture?

  • It is hard to turn the crank.
  • Press cake does not leave the cap.
  • No oil production.
  • Washer behind the screw shows extreme wear.
  • Sometimes also some black oil at the shaft hole of the screw.
  • The seed is ground to a mash.

Piteba tool

In the manual you can read how the moisture of the nuts or seeds can be corrected. Without the need for equipment. The Piteba tool is used as a balance to weigh a certain amount of seed. A scoop of water (= 15 ml) is then added to the weighed amount. After 2 days this seed can be pressed.

This is a rough way to improve the press results. A more accurate method is described below.

Moisture determination

In order to get the best results, determining the moisture content of the seeds or nuts is very important.

Here is a simple method:

Weigh exactly 100 grams of the seed or nuts to be pressed. This is dried in an oven at 100-105 ° C for 1½ hours. Nuts dry better if they are crushed or ground prior to drying. In the oven, the water evaporates and a dry product remains. After drying the seeds or nuts are weighed again and the weight noted. If there was moisture in it, the weight is reduced after drying. If the weight is still almost 100 grams, there was very little moisture and therefore more water per kilo must be added.

Weigh exactly 100 grams of the seeds or crunched nuts.

Dry it in an oven at 100-105 °C for 1½ hours .

Weight after drying (gram)

Amount of water (g or ml)

to be added per kilogram
of seeds or nuts


100 ml/kg


90 ml/kg


80 ml/kg


70 ml/kg


60 ml/kg


50 ml/kg


40 ml/kg


30 ml/kg


20 ml/kg


10 ml/kg


Do not add water

89 or less

Seed too moist: first dry the batch of seeds or nuts, then take a new sample of 100g and determine the moisture content again.

After adding water

After adding the appropriate amount of water, the seeds or nuts should be stored in a plastic bag for at least 2 days and can then be pressed. Of course very small seeds will absorb the water faster and then one day of storage will be enough.