Bitter almond oil (free from hydrogen cyanide) contains benzaldehyde as its main component. Benzaldehyde does not occur as such in the plant, but is formed, together with hydrogen cyanide, by the hydrolytic cleavage of the glycoside amygdalin. Amygdalin is present in bitter almonds, the seeds of Prunus dulcis var. amara (DC.) Buchheim, and ripe apricot kernels, Prunus armeniaca L. (Rosaceae).The press cake, which remains after removal of the fatty oils, is macerated with water and left to stand for several hours, after which the “essential oil” is separated by steam distillation. The crude oil contains 2–4% hydrogen cyanide, which is removed by washing with alkaline solutions of iron(II) salts. Subsequent redistillation yields an oil free from hydrogen cyanide. It is a colorless to slightly yellow liquid with an intense, almond-like, cherry aroma and a slightly astringent, mild taste. d2525 1.025–1.065; n20D 1.5350–1.5550; acid value: max. 8; solubility: 1 vol inmax. 6 vol 50% ethanol. HCN content: <0.01%; benzaldehyde content by GC: min. 98%. Bitter almond oil is used almost exclusively in natural aroma compositions.