Since the dawn of civilization (and maybe even before then), botanical extracts and essential oils have been valued for their medicinal properties, cosmetic value, aromas, flavors, and more.
All over the world, people recognize these useful characteristics in various flowers, bark, stems, leaves, roots, and resins. As a result, a wide variety of methods have been developed to extract the active and valuable chemical compounds from plant material, or biomass.
Extraction describes a process of liquid/solid separation. In a nutshell, it refers to the addition of a liquid to solid raw material (which has, in most cases, been through a particle size reduction process). After liquid has been allowed to dissolve the desirable key compounds from the biomass, the solids are separated out of the liquid in a subsequent process.
Over time, extraction methods have grown more sophisticated, from early soaking or fermentation processes to today’s super- and subcritical CO2 extraction.
Products intended for human ingestion, inhalation, or topical application need an experienced essential oil contract manufacturer. Extraction experts put care and technological know-how into maximizing valuable compounds while reducing and even eliminating unwanted components.
In this article, we’ll take a look at some of the most in-demand botanical extract products. We’ll also review key methods used to produce herbal extracts and the most important capabilities to look for in a trusted toll processor or contract manufacturer.
Essential oils are concentrated volatile oils — so they evaporate quickly in air. Most essential oils are lighter than water, with a few exceptions like cinnamon and bitter almond. This weight difference facilitates their separation after the initial extraction process.
Generally, large volumes of plant biomass are needed to produce essential oils. The oils’ makeup can be very complex, including hundreds of volatile components such as alcohols, esters, ethers, hydrocarbons, aldehydes, terpenes, and more.
Many essential oils have long been used for fragrance, flavor, and medicinal purposes. Others may be used as antibacterial agents or ingredients in insect repellents or even pesticides.
What is a botanical extract? Extracts are made up of the extracted phytochemicals left in solvent (such as water, glycerin, or alcohol). Tinctures, which use alcohol as a solvent, are common extracts. Vanilla extract is a very commonly used alcohol-based extract.
Absolutes are another type of product from the extraction process. An absolute is the result of a more complex process that uses chemical solvents. Extraction is followed by evaporation or distillation to remove the solvent. The result is a waxy, highly concentrated extracted product that’s often in demand for its fragrance.
Water distillation may be one of the oldest methods used for botanical extraction. In this method, plant material is boiled in water to release the essential oils into the steam. The steam is then condensed, and the plant oils separate from the water.
Water distillation is a simple process, but it may leave behind valuable compounds. And for some plants, long exposure to the high temperatures needed to boil water can degrade the quality of the resulting product.
Steam distillation is a more commonly used method, especially for more heat-sensitive herbs and botanicals such as lavender or other flowers. Steam quickly vaporizes volatile compounds, and the vapor is condensed, allowing the two fractions (water and extracted compounds) to separate.
Fractional distillation takes this concept a step further, heating steam to specific temperatures at which each desired component vaporizes. This process fractionates the different chemical compounds in a plant, collecting them in separate batches. Camphor and ylang-ylang are commonly known products of fractional distillation.
Fractional distillation is also used to redistill oils to remove unwanted or toxic components. Almond oil, for example, is fractionally redistilled — or rectified — to remove naturally occurring hydrocyanic acid.
Finally, some hydrosols, or aromatic waters like rosewater and orange flower water, are valuable by-products of the distillation process.
While water is technically a solvent, other solvents are often used for herbal and botanical extraction. Commonly used solvents can include methanol, ethanol, hexane, and petroleum ether. Solvents are selected for suitability with the specific desired solute, and are added to plant biomass after it has been finely milled to optimize penetration and extraction.
Solvent extraction can be a useful method for more delicate plant materials whose essences aren’t readily extracted by steam. Solvent processing requires expertise and technical process control, from the milled fineness of the plant biomass and solvent selection to the fine adjustments of time and temperature controls on extraction equipment.
Some solvents can leave a residue, and acceptable residue levels are strictly regulated. Lab analysis capabilities such as gas chromatography-mass spectrometry (GC-MS) are vital for determining the composition and quality of the final botanical extract product.
Pressurized carbon dioxide can shorten extraction time and eliminate solvent residue concerns. Under pressure, CO2 can reach a subcritical or supercritical state. In this state, the carbon dioxide acts like a liquid solvent, capable of extracting essential compounds from plant material more completely than steam.
Unlike many other solvents, CO2 is nontoxic and nonflammable, and leaves no residue behind. Because it uses relatively low temperatures, this extraction method is less likely to degrade flavors, colors, or essences, for a clean, unadulterated, high-quality end product.
By controlling pressures and flow rates, extraction experts can target specific phytochemicals and leave behind unwanted compounds. As pressure is relieved, the CO2 simply dissipates, leaving a high-quality extract composed of low molecular weight compounds such as ethers, esters, terpene, hydrocarbons, ketones, and alcohols.
CO2 extraction is a sought-after toll processing capability for hemp and other floral essential oil manufacturers. It is a preferred method for many herbs including melissa, rosemary, lavender, and kava kava, among others.
While solvent extraction is sometimes used for these products, supercritical carbon dioxide reduces the need for further refinements. This can mean shorter processing time, in addition to very pure and potent products.
Purity and potency are two key qualities consumers value in botanical extracts. That’s why analytical and testing capabilities are just as important as the extraction equipment and capabilities your contract or toll manufacturer offers.
Your specific botanical extraction process may require crucial pre-process steps, from milling to meet a particle size specification, to decarboxylation for specialty CBD extracts. So be sure to look for a contract or toll manufacturer with all these capabilities under one roof.
Look for a trusted toll processor that can also provide analytical lab services for quality control and reporting, and a quality management system in place. CGMP and FSSC 22000, as well as organic, kosher, and halal certifications, and help ensure your product reaches and appeals to your target consumers.
Additional services like GMP liquid bottle filling, labeling, packaging, and logistics can eliminate potential supply chain bottlenecks and improve your speed to market.
You might be surprised at the efficiency you can achieve by entrusting your extraction projects to a single, start-to-finish toll processing expert. Look for a team capable of handling every step and advising you on process improvements and optimizations along the way.
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