Making oil from plants comes down to separating the oil already stored in a plant’s seeds, nuts, flowers, or leaves from the rest of the solid material. The method you use depends entirely on what kind of oil you want: a concentrated aromatic essential oil, a fatty cooking or carrier oil, or a simple herb-infused oil. Each requires different equipment, different plant parts, and different levels of effort.
Essential Oils vs. Carrier Oils vs. Infused Oils
These three categories of plant oil are fundamentally different products. Essential oils are highly concentrated volatile compounds extracted from aromatic plants like lavender, peppermint, or eucalyptus. They evaporate at room temperature and carry the plant’s scent. Carrier oils (sometimes called vegetable oils or fixed oils) are the fatty oils pressed from seeds and nuts, such as sunflower, olive, or coconut oil. They don’t evaporate and are used for cooking, skincare, and as a base for diluting essential oils.
Infused oils are the simplest to make. You steep plant material in a carrier oil to transfer flavor or beneficial compounds into the oil. Think garlic olive oil or calendula-infused coconut oil. No special equipment needed.
The extraction method, equipment cost, and yield vary dramatically across these three types. Essential oils have notoriously low yields: lavender flowers produce roughly 3% oil by weight through steam distillation, meaning you need large volumes of plant material for even a small bottle. Fatty seed oils yield far more generously, though exact amounts depend on the seed variety and pressing method.
Steam Distillation for Essential Oils
Steam distillation is the most common way to extract essential oils and the method most accessible to beginners. The principle is simple: steam passes through plant material, causing the tiny oil-containing structures in leaves, flowers, or bark to release their aromatic compounds. The steam carries these compounds upward into a condenser, where the vapor cools back into liquid. Because essential oil and water don’t mix, they naturally separate in the collecting vessel, with the oil floating on top.
To set this up at a small scale, you place plant material in a pot or flask and add enough water to just cover it. As the water heats to a boil, steam rises through the plant material and picks up the volatile oils. The steam then travels through a tube or coil surrounded by cold water (the condenser), which turns it back into liquid. You collect this liquid in a jar or graduated cylinder and let the oil layer separate from the water beneath it. That water, called a hydrosol or floral water, contains trace amounts of the oil’s compounds and is itself a useful product.
Home distillation kits designed for essential oils typically include a boiler pot, a column for plant material, a condenser coil, and a separator. Copper and stainless steel are the standard materials. The process takes anywhere from 30 minutes to several hours depending on the plant. Lavender and peppermint distill relatively quickly, while tougher materials like sandalwood or vetiver roots require much longer.
The biggest challenge is yield. You may process several pounds of fresh lavender to get a few milliliters of oil. Harvesting at the right time (typically just before or during peak bloom) and distilling fresh material improves your output.
Cold Pressing for Seed and Nut Oils
Cold pressing is how most high-quality carrier oils are produced. A mechanical press crushes seeds or nuts, forcing the oil out while keeping temperatures below 49°C (120°F). Staying under this threshold preserves the oil’s nutrients, flavor, and color, which is why cold-pressed oils command higher prices.
The two main press types are screw presses (also called expeller presses) and cage presses. In a screw press, an auger turns inside a barrel, grinding and compressing the seeds as they move forward. Oil seeps out through small gaps in the barrel while the dry leftover material (called meal or cake) is pushed out the end. You can adjust the pressure by changing the gap at the exit, and the screw speed controls how fast seeds move through. Faster speeds mean more oil per hour but slightly lower extraction efficiency, because the oil has less time to separate from the solids.
For home use, small tabletop screw presses handle seeds like sunflower, sesame, flax, and peanut. These manual or electric units are compact enough for a kitchen counter. The key variables are seed moisture content and temperature. If your seeds are too dry, friction in the press generates extra heat, pushing you past that 120°F cold-press limit. Most seeds press best at a moisture content between 6% and 10%, though this varies by species.
After pressing, the oil is cloudy with fine seed particles. Let it settle in a jar for a day or two, then pour off the clear oil from the sediment. You can also filter it through cheesecloth or a fine mesh for faster results. Homemade pressed oils lack the preservatives and refining of commercial versions, so store them in dark glass bottles in a cool place and use them within a few months.
Solvent Extraction for Commercial Production
For seeds with lower oil content, or for delicate flowers where heat would destroy the aromatic compounds, solvent extraction is the industry standard. The process works by soaking plant material in a chemical solvent (hexane is the most widely used) that dissolves the oil. The oil-enriched solvent, called miscella, is then heated to evaporate the solvent away, leaving behind the crude oil. The evaporated solvent is condensed, captured, and recycled back into the process.
The remaining solid material also needs cleaning. Steam is injected to drive off any trapped solvent, and the defatted meal is heated just enough to evaporate residues without destroying its nutritional value (it’s often sold as animal feed). The crude oil then goes through refining steps to remove impurities, contaminants, and any remaining solvent traces.
This isn’t a home-friendly method. It requires specialized equipment, careful ventilation, and solvents that are flammable and potentially hazardous. It’s worth understanding because most inexpensive cooking oils on store shelves are produced this way, and it explains why cold-pressed oils taste and behave differently.
Cold Pressing Citrus Peels
Citrus essential oils are a special case. The oil glands sit right in the outer rind, and simple mechanical pressure releases them. Commercial producers use machines that puncture and press the peel while spraying water to wash the oil away, then separate the oil from the water by spinning it in a centrifuge.
At home, you can extract small amounts of citrus oil by grating or zesting the peel and pressing the gratings through cheesecloth. This gives you a mixture of oil and juice. Alternatively, you can peel citrus fruits, let the peels dry slightly, and press them in a garlic press or similar tool over a small bowl. The yield is tiny, but the oil is fresh and intensely fragrant. For larger quantities, adding citrus peel to a steam distillation setup also works, though the heat slightly changes the oil’s character compared to cold-pressed versions.
Enfleurage for Delicate Flowers
Some flowers, like jasmine and tuberose, are too fragile for steam distillation. Their aromatic compounds break down under heat. Enfleurage is an old technique that captures these scents without any heat or pressure. You spread a layer of odorless solid fat (traditionally purified animal fat, though coconut oil works) onto a glass plate, then press fresh flower petals into the fat. Over the course of one to three days, the fat absorbs the flower’s fragrance. You remove the spent petals and replace them with fresh ones, repeating the process dozens of times until the fat is saturated with scent.
The scented fat (called a pomade) can be used directly or washed with alcohol to separate the aromatic compounds from the fat. This is extremely labor-intensive and produces small quantities, which is why true enfleurage products are rare and expensive. It’s a rewarding project if you grow jasmine or gardenias and want to capture their scent authentically, but it’s not practical for producing oil in any meaningful volume.
Making Herb-Infused Oils at Home
Infused oils are by far the easiest plant oils to make and require no special equipment. You submerge dried herbs, garlic, or other aromatics in a carrier oil and let time do the work. Olive oil and canola oil are popular choices because they contain fewer of the fatty acids that turn rancid quickly.
A standard ratio is 1 part plant material to 10 parts oil. Place dried herbs in a clean jar, pour oil over them, seal the jar, and let it sit at room temperature for 1 to 10 days. The flavor and potency increase the longer you infuse. If you want faster results, you can heat the oil to 140°F (60°C) for about 5 minutes to speed up the transfer of compounds.
There’s one important safety consideration with infused oils: fresh herbs and garlic contain water, which creates conditions for bacterial growth in the oxygen-free environment inside the oil. If you use fresh plant material, refrigerate the oil and use it within 2 to 4 days. Dried herbs are safer for longer storage. Even then, keep the finished oil refrigerated and use it within three months.
How Oil Quality Is Tested
If you’re producing essential oils and want to verify their purity or composition, the standard tool is gas chromatography paired with mass spectrometry. This technique separates the oil into its individual chemical components and identifies each one, revealing exactly what’s in your oil and in what proportions. It can detect adulteration (like synthetic compounds added to stretch a batch) and confirm that the oil matches the expected profile for its plant species.
International standards like ISO 11024 define the chromatographic profiles that specific essential oils should match. For lavender oil, the standard identifies 170 individual compounds that characterize authentic oil. For home producers, sending a sample to a third-party testing lab is the most accessible way to verify quality, especially if you plan to sell your oil.
For fatty carrier oils, quality testing focuses on different markers: free fatty acid content (indicating freshness), peroxide value (measuring oxidation), and moisture levels. These tests are simpler and some can be done with basic kits, though lab testing gives more precise results.
Choosing the Right Method for Your Plant
- Aromatic herbs and flowers (lavender, rosemary, mint): Steam distillation is your best option. These plants have enough volatile oil to make the process worthwhile, and home distillation kits are widely available.
- Oily seeds and nuts (sunflower, sesame, flax, peanut): A small screw press gives you fresh, unrefined oil. Look for tabletop models rated for home use.
- Citrus fruits (lemon, orange, grapefruit): Cold press the peels by hand for small batches, or add peels to a steam distillation setup.
- Delicate flowers (jasmine, tuberose, gardenia): Enfleurage if you have patience and plenty of flowers. Otherwise, infuse them into a carrier oil.
- Culinary herbs and garlic: Simple oil infusion at room temperature or with gentle heat. No extraction equipment needed.
The scale you’re working at matters as much as the plant itself. A backyard lavender patch can supply enough material for a small steam distillation run. Pressing oil from seeds only makes practical sense if you’re growing or buying seeds in bulk, since even a small press needs a steady feed of material to operate efficiently. Start with infused oils or small-batch steam distillation if you’re experimenting, and scale up once you understand the yield and effort involved with your specific plants.