Neem Seed Oil Extraction — Traditional Cold-Press Method of Andhra Pradesh

Neem (Azadirachta indica, Meliaceae family) is an evergreen tree native to the Indian subcontinent. This tree grows to a height of 15-20 meters, with broad, dense, umbrella-shaped green branches. The leaves are compound type, 20-40 cm long, with 8-19 small leaflets per leaf. These leaflets have serrated margins. The tree bears white, fragrant flowers between March-May. The fruits ripen between May-August — changing from green to yellow-green. Each fruit is an oval drupe 1-2 cm long, containing a hard seed kernel inside. A mature tree yields 30-50 kg of fruits per year. Neem contains over 300 biologically active compounds, of which azadirachtin is the most important — it is a potent natural insecticidal chemical.

In Andhra Pradesh, neem fruits ripen and fall between June and August — the onset of the monsoon season. Ripe fruits change from green to yellow-green and fall naturally. The pulp of fallen fruits is soft and sweet — birds and bats eat the pulp and disperse the seeds. The best time for collection is early morning, picking up fresh fruits that fell overnight. Fruits left on the ground for more than 2-3 days after falling begin to rot — rotted pulp reduces seed quality. Neem trees grow naturally along roadsides, field boundaries, and in villages — every village in rural Andhra Pradesh has ten to hundreds of neem trees.

Start collection between 6:00-9:00 AM. Gather the yellow-green fruits fallen under the tree. Leave behind green (unripe) fruits — their seeds are not fully developed, and oil percentage is low. Also leave black, decomposed fruits. One person can collect 15-25 kg of fruits per day. Fill collected fruits in burlap sacks — do not tie in plastic sacks, as moisture gets trapped and decomposition starts. Do not fill the sack more than three-quarters, as fruits at the bottom get crushed. Start processing collected fruits on the same day or the next day.

The outer pulp must be removed from the collected fruits — only the seed is used for oil extraction. Soak the fruits in a large bucket of water — soaking for 12-24 hours softens the pulp for easy removal. Remove the soaked fruits and squeeze by hand to separate the pulp. The seeds are hard, oval-shaped, and grayish-white in color. Do not pour the pulp-soaked water into drains — this water contains saponins, which are harmful to fish. Instead, pour the pulp water into a compost pit — it makes good organic fertilizer. From 10 kg of fruits, approximately 5-6 kg of seeds are obtained.

After depulping, wash the remaining pulp fibers adhering to the seeds thoroughly in clean water. Change the water and wash 2-3 times — until the water runs clear. If pulp residue remains on the seeds, mold will develop during drying and oil quality will decrease. Take the washed seeds immediately for drying — do not pile wet seeds together, as they will heat up and rot. Clean seeds have a rough, grayish-brown outer shell.

Spread washed seeds in a single layer on a mat (mat) and dry them in the sun. Do not dry directly on the ground — moisture will return. Dry on a mat, bamboo mat, or tarpaulin. Turn 3-4 times a day — it should dry evenly on all sides. Well-dried seeds are ready in 3-5 days. When a dried seed is tapped with a finger, it should crack hard with a 'tuck' sound — if it bends softly, there is still moisture. The moisture percentage should be less than 10%. Cover with tarpaulin at night, protect from rain. Oil from improperly dried seeds contains high free fatty acid (FFA), reducing quality.

Dried neem seeds have a hard outer shell (shell), inside which there are 1-2 kernels (seed kernels) — these are the parts that yield oil. The kernel contains 40-50% oil content. Gently crack the seeds with a small stone roller or wooden mallet to break the shell — if too much force is applied, the kernel will be damaged. Separate the shell pieces from the kernel. The kernel is white-yellowish in color and slightly oily. Do not discard the shells — they can be used as organic fertilizer. Collect the kernels in a clean container. From 10 kg of seeds, approximately 5-6 kg of kernels are obtained.

Coarsely crush the separated kernels in a stone mortar or grinder — do not grind too finely, they should remain as coarse crush. If ground too finely, they will turn into paste during pressing and the oil will not separate properly. Keep the coarsely crushed kernels at room temperature (25-30°C) before putting them in the pressing machine. Do not heat — heating is prohibited in the cold-pressing method, because heat causes azadirachtin to degrade (azadirachtin degrades above 60°C). Take 3-5 kg of crushed kernels per batch.

Place the kernels soaked in water into a traditional wooden oil press (ghani) or manually operated screw press and apply pressure. The wooden ghani is a traditional Indian oil pressing method — operated by a machine turned by oxen or by hand. The modern manual screw press is suitable for small-scale production. Ensure that the temperature during pressing remains below 50°C — this is the definition of cold-pressing. The oil flows slowly, drop by drop — do not hurry and press at high speed. From 5 kg of kernels, approximately 1.5-2 liters of neem oil is obtained (30-40% yield). After pressing, remove the remaining press cake and set it aside — it is a valuable organic fertilizer and insecticide.