Making cannabis oil at home involves three core steps: activating the cannabinoids in your flower through heat, infusing them into a carrier oil, and then straining and storing the finished product. The entire process takes roughly two to three hours, and the most common method uses nothing more than an oven, a slow cooker, and coconut oil. Getting the details right, especially temperature and timing, is what separates a potent, consistent oil from one that’s weak or harsh-tasting.
Why Raw Cannabis Needs Heat First
Fresh cannabis flower contains THCA, an acidic compound that won’t produce psychoactive or many therapeutic effects on its own. Heating it through a process called decarboxylation strips away a carbon molecule and converts THCA into active THC (or CBDA into CBD, if you’re working with hemp flower). Skip this step and your oil will be far less potent than expected.
Spread your ground flower evenly on a parchment-lined baking sheet and bake it in the oven. For THC, 240°F (115°C) for 30 to 40 minutes is the standard. If preserving the flavor and aroma matters to you, drop the temperature to 220°F (105°C) and extend the time to 45 to 60 minutes. CBD flower needs longer at the same temperature: 60 to 90 minutes at 240°F. The flower should look lightly toasted and dry when it’s done, not charred. Keeping a stable temperature matters more than speed. If you exceed 300°F, cannabinoids start breaking down rapidly and you’ll lose potency.
Choosing a Carrier Oil
Cannabinoids are fat-soluble, so they need a lipid to bind to. The three most common choices are coconut oil, MCT oil, and olive oil, and the differences go beyond taste.
MCT oil (refined from coconut or palm kernel oil) leads to better absorption in the gut compared to oils made from long-chain fats like olive oil. Research in the journal Molecules also found that terpenes, the aromatic compounds responsible for flavor and some therapeutic effects, stayed stable for the full 90-day study period in MCT formulations. In olive oil, terpene levels dropped noticeably after just 15 to 30 days. Both oils kept cannabinoid potency steady for at least 60 days, so either works for short-term use, but MCT has the edge for absorption and long-term flavor.
Unrefined coconut oil is another popular option. It solidifies at room temperature, which makes it easy to portion into molds or capsules. If you plan to cook with your oil, olive oil gives a more neutral savory flavor. For sublingual use (drops under the tongue), MCT oil’s thin consistency and mild taste make it the easiest to work with.
The Infusion Process
A common starting ratio is 1 ounce of decarboxylated flower to 16 ounces (2 cups) of oil. This produces a moderately potent oil suitable for most uses. You can double the flower for a stronger product or halve it for something milder.
Slow Cooker Water Bath Method
This is the most forgiving approach for beginners. Combine your decarbed flower and oil in a mason jar, seal the lid loosely, and place the jar in a slow cooker. Fill the cooker with warm water until it covers the jar by about an inch. Set it to low and let it infuse for 4 to 6 hours, checking periodically that the water level hasn’t dropped too far.
The water bath serves a specific purpose: it acts as a buffer that prevents the oil from ever exceeding 212°F (the boiling point of water at sea level). Since cannabinoids and terpenes degrade above 300°F, and common terpenes like myrcene and limonene evaporate around 330 to 350°F, the water bath gives you a wide safety margin. You get gentle, even heat without the risk of scorching.
Stovetop Double Boiler
If you don’t have a slow cooker, a double boiler works on the same principle. Place your oil and flower in the top pot, keep the water in the bottom pot at a low simmer, and stir occasionally for 2 to 3 hours. Use a kitchen thermometer to keep the oil between 160°F and 200°F.
Straining and Filtering
Once infusion is complete, you need to separate the plant material from the oil. At minimum, pour the mixture through a fine-mesh strainer lined with cheesecloth into a clean jar. Squeeze gently to get as much oil out as possible, but don’t wring it aggressively. Over-squeezing pushes chlorophyll and fine plant particles into your oil, giving it a bitter, grassy taste and a darker green color.
For a cleaner product, strain through a finer material. Coffee filters or reusable mesh bags rated at 100 microns or finer will catch smaller particles that cheesecloth misses. Filtration does more than improve appearance. Removing chlorophyll and plant waxes actually helps maintain cannabinoid stability over time, since those materials can break down and affect the oil’s quality during storage. Commercial producers use activated carbon filters to strip color and odor, but for home use, a double pass through cheesecloth followed by a coffee filter gets you most of the way there.
Estimating Potency
Without lab testing, you can’t know your oil’s exact strength, but a simple formula gets you in the right ballpark. Start with the THC percentage of your flower. If you have 5 grams of flower testing at 15% THC, that’s 750 mg of total THC (5,000 mg × 0.15). Not all of that transfers into the oil during infusion. A realistic transfer rate is around 70%, which brings your effective total down to about 525 mg of THC in the finished batch.
Divide that number by the volume of oil you used. If you infused into 8 ounces (roughly 240 ml), each milliliter contains about 2.2 mg of THC. A standard dropper holds approximately 1 ml, so each dropper would deliver roughly 2 mg. This kind of math lets you start with a low, controlled dose and adjust from there. If you don’t know your flower’s THC percentage, most dispensary flower falls between 15% and 25%.
Solvent-Based Extraction (FECO/RSO)
Some people make a more concentrated oil using food-grade ethanol instead of a carrier fat. This method produces what’s often called Full Extract Cannabis Oil (FECO) or Rick Simpson Oil (RSO). You soak decarbed flower in high-proof ethanol, strain out the plant material, and then evaporate the alcohol, leaving behind a thick, dark concentrate.
This approach creates a far more potent product, but it carries real safety risks. Ethanol vapor is highly flammable. Oregon OSHA requires that areas where ethanol is used for extraction have explosion-proof ventilation systems providing at least one cubic foot of airflow per minute per square foot of floor space. Every potential ignition source matters: open flames, hot surfaces, sparks, even cell phones in certain conditions. If you choose this method, work outdoors or in a space with strong cross-ventilation, use only food-grade ethanol (not isopropyl alcohol), and never apply direct heat to an open container of alcohol. Use a double boiler or a purpose-built evaporation setup, and keep the temperature well below ethanol’s boiling point of 173°F to allow slow, safe evaporation.
For most home users, the fat-infusion method is simpler, safer, and produces an oil that’s easy to dose and cook with.
Storage and Shelf Life
Properly stored cannabis oil remains potent for one to two years. The three enemies of cannabinoid stability are light, heat, and air. Store your finished oil in an airtight amber glass jar or bottle, which blocks the UV light that accelerates THC degradation. Keep it in a cool, dark place like a pantry or refrigerator. Coconut oil-based preparations will solidify in the fridge but return to liquid at room temperature within minutes.
If you made a large batch, consider dividing it into smaller jars so you’re not repeatedly opening and exposing the full supply to air. Label each jar with the date and your estimated potency per milliliter. Terpene-rich oils stored in MCT hold their flavor profile longer than those made with olive oil, but either will maintain cannabinoid potency for at least two months at room temperature and longer when refrigerated.