Essential oils are extracted from a biomass through milling in a solvent to form a solution of the essential oil in the solvent. The solvent is or is part of a cover than reduces oxidative and other degradation of the essential oil during milling and isolation. The solubilized essential oil may be allowed to adhere to the originating milled biomass to form a feed or nutritional supplement. The solvent may be evaporated from the solubilized essential oil to form an essential oil concentrate. This essential oil concentrate may be used directly, adhered to a different biomass than the originating biomass, or used in combination with pharmaceutical, nutritional, or feed preparations. The essential oil concentrate is preferably adhered to the different biomass through milling under a cover to reduce oxidative and other degradation. The essential oil may be astaxanthin, capsaicin compounds, or cannabinoids.
