Making a plant extract means pulling the active compounds out of plant material using a liquid solvent, most commonly alcohol, glycerin, oil, or water. The method you choose and the solvent you use determine which compounds end up in your final product, how potent it is, and how long it lasts. Here’s how to do it right, with the specific ratios and timelines that matter.
Choose Your Solvent Based on What You Want to Extract
Plants contain a wide range of useful compounds: phenolics, flavonoids, alkaloids, and terpenoids, among others. Each of these has a different polarity, which means each dissolves best in a specific type of liquid. Research on solvent polarity and plant extraction shows that the yield of phenolic and flavonoid compounds increases as solvent polarity rises, then drops sharply at very high polarity (pure water). This is why mid-polarity solvents like ethanol consistently outperform water alone.
Here’s a practical breakdown of the four most accessible solvents:
- Ethanol (alcohol): The most versatile option. Extracts a broad range of compounds including alkaloids, flavonoids, and some resins. A mix of ethanol and water (typically 40% to 60% alcohol by volume, like 80- to 120-proof vodka) covers a wide polarity range and pulls both water-soluble and alcohol-soluble constituents.
- Water: Good for mucilage, some polysaccharides, and mineral salts. Teas and decoctions are water extracts. The downside is poor shelf stability without refrigeration or added preservative.
- Glycerin: A thick, sweet, alcohol-free liquid that works well for people avoiding ethanol, including children. It extracts fewer compounds than alcohol and is less effective at breaking through the cell walls of dried plants. A glycerite must contain at least 55% glycerin to resist microbial growth, and even then the shelf life is only one to two years stored in a cool, dark place.
- Oil: Best for fat-soluble compounds like certain terpenoids and carotenoids. Oil infusions are common for topical use (salves, massage oils) but are not suitable for extracting water-soluble compounds.
Get the Plant-to-Solvent Ratio Right
The ratio of plant material to solvent determines how concentrated your extract will be. The traditional standard for tinctures uses weight-to-volume measurements: grams of dried herb per milliliters of solvent.
For most herbs, the standard tincture ratio is 1:5, meaning 1 gram of dried plant material per 5 mL of solvent. For stronger “potent” preparations (herbs that are used in smaller doses), the traditional ratio is 1:10. Professional-grade liquid extracts called fluidextracts use a 1:1 ratio, where 1 mL of finished product represents 1 gram of crude dried material, but these require specialized equipment to produce.
If you’re working with fresh plant material, you need more solvent because the plant already contains water. A common approach is a 1:2 ratio (1 gram fresh herb to 2 mL of solvent) using high-proof alcohol, since the water content of the fresh plant dilutes the alcohol concentration. All ratios should be calculated based on the dry weight of the plant material, even when you start with fresh herbs, to keep things consistent.
Glycerin Ratios
For fresh plants, simply cover the material completely with glycerin, filling the jar to within one inch of the top. For dried plants, dilute the glycerin with distilled water at a 3:1 ratio (three parts glycerin to one part water) before pouring it over the herb. The added water helps the glycerin penetrate the dried cell walls more effectively.
Maceration: The Simplest Extraction Method
Maceration is the most common home method. You coarsely chop or grind your plant material, place it in a glass jar, pour solvent over it until the plant is completely submerged, seal the jar, and wait.
The minimum steeping time is three days, but most herbalists let tinctures macerate for two to six weeks, shaking the jar once or twice daily. Longer maceration times are especially useful for tough plant parts like roots and bark. Traditional maceration protocols used in commercial production run 14 to 38 days with the batch stirred twice daily. The tradeoff: maceration is slow and recovers only about 35% to 38% of the active compounds from the herb, according to extraction efficiency data from pharmaceutical research. For home use, this is still perfectly adequate to produce an effective extract.
Keep the jar in a cool, dark place during maceration. Light and heat accelerate oxidation, which degrades many of the compounds you’re trying to preserve. When the steeping period is complete, strain the liquid through cheesecloth or a fine mesh strainer, squeeze out as much liquid as possible from the plant material (called the marc), and bottle the finished extract in a dark glass container.
Percolation: Faster but More Involved
Percolation pushes solvent slowly through a column of packed plant material, extracting compounds more efficiently than passive soaking. It’s faster and yields a more concentrated product, recovering roughly 45% of active compounds versus maceration’s 35% to 38%.
The basic process works like this: grind the herb to a consistent particle size, soak it in your solvent for about two hours to let the material swell, then pack it evenly into a cone-shaped vessel (a percolator) with a filter at the bottom. Pour solvent on top and let it saturate the herb completely. After an initial 24-hour soak, open the valve and let the liquid drip through at a slow, steady rate of about 4 to 6 drops per minute for every 100 grams of starting material.
The key challenge is packing the material evenly. If channels form in the herb bed, solvent flows through the path of least resistance and leaves pockets of plant material untouched. Percolation works well if you’re making extracts regularly and want higher yields, but for occasional use, maceration is simpler and requires no special equipment.
Oil Infusions: Cold and Warm Methods
Oil-based extracts are made by submerging plant material in a carrier oil like olive, sweet almond, or jojoba oil. The cold method is the most protective of delicate compounds: combine the oil and plant material in a sealed container, keep it in a dark, cool place, and let it sit for two to three weeks with occasional agitation.
A warm method speeds the process up. Gentle heat helps release fat-soluble compounds faster, but you need to keep temperatures low. Research on heat-assisted oil maceration uses room temperature with constant agitation, followed by extended storage in the dark. If you apply heat at home, keeping the oil below 40 to 50°C (104 to 122°F) helps prevent oxidation and degradation of sensitive compounds. A slow cooker on its lowest setting or a double boiler works for this, typically over 2 to 4 hours. Strain and store in a dark glass bottle. Oil infusions generally last 6 to 12 months, and refrigeration extends their life.
How to Keep Your Extract Shelf-Stable
Alcohol is the most reliable preservative for liquid extracts. An ethanol concentration of at least 20% by volume is enough to kill most yeast and bacteria outright, while concentrations of 10% or higher have been shown to prevent microbial contamination entirely over periods exceeding six months. Most tinctures made with 80-proof vodka (40% alcohol) are well above this threshold and will last for years when stored properly.
Glycerites are less stable. The 55% glycerin minimum is the floor for preservation, and even then you should store them in the refrigerator after opening and use them within one to two years. Water-based extracts (teas, decoctions) have no meaningful shelf life. Use them within 24 to 48 hours or freeze them in ice cube trays for longer storage.
For all extracts, dark glass bottles (amber or cobalt blue) protect against light degradation. Store in a cool location away from direct sunlight and heat sources. Label every bottle with the plant used, solvent, ratio, and date of preparation.
Plants to Avoid Extracting
Not every plant is safe to extract, even if it has a long history of traditional use. The most significant concern is pyrrolizidine alkaloids, a class of compounds found in several common herbs that can cause liver damage and are linked to tumor development.
Comfrey is the most well-known example. Despite centuries of use as a medicinal herb and tea ingredient, it contains pyrrolizidine alkaloids that cause liver fibrosis and cancer in animal studies. The FDA issued a warning against consuming herbal products containing comfrey in 2001. Coltsfoot, historically used as a cough remedy, contains two pyrrolizidine alkaloids (senecionine and senkirkine) with the highest mutagenic activity of any known compound in this class. Both plants are still sold online as supplements.
Other compounds to be aware of include aristolochic acids (found in plants of the Aristolochia genus) and safrole (found in sassafras root bark), both linked to cancer development and largely unregulated in herbal supplement markets. Before extracting any plant, confirm its safety through a reputable herbal reference. If you’re wildcrafting (harvesting from nature), accurate plant identification is critical since many toxic plants closely resemble edible or medicinal ones.