1. The Operating Principle: The Screw Press

Most modern oil presses are screw presses. The seeds are fed through a hopper into a cylinder. A rotating screw presses the material with enormous pressure against a nozzle or sieve.

• The oil: Escapes through fine slots (perforated sieve).
• The press cake: The solid residues (pellets) exit at the front of the nozzle and are perfect as feed for e.g. chickens, pigs… depending on the seed.

2. Cold Pressing vs. Hot Pressing

• Cold pressing: The goal is to extract the oil without external heat in order to preserve vitamins and aromas. Friction heat is always generated, but it should remain minimal.
• Heating collar: Many presses are equipped with a heater. This is often used to preheat the machine so that oil flows better with tougher seeds, without reducing quality through overheating.

3. Application Areas

Oil presses are divided into 3 groups based on their use.

• Standard seeds – rapeseed, mustard, camelina, sunflower, etc.
• Hard seeds (low oil content and high fiber) – soybeans, hemp, grape seeds, rosehip seeds, prickly pear
• Oil-rich seeds – all types of nuts

4. Oil Production Process

• Clean the seeds
• Optionally crush and/or dehull depending on the seed
• Press the oil
• Filter
• Bottle