Dietary phytochemicals are thought to reduce the incidence of chronic degenerative diseases. The concentration of these phytochemicals has been extensively studied, but less is known about their stability during food processing. The objective of this study was to determine the stability of lignans and other phytochemicals during the vinification and brewing processes. The amount of secoisolariciresinol diglucoside (SDG), gallic acid, caffeic acid, coumaric acid, chlorogenic acid, and ferulic acid increased up to 45 % during the vinification process; however, the amount of folic acid remained unchanged. SDG content was determined in barley for the first time. The SDG content also varied among barley varieties and showed a year-to-year variation. In addition, no SDG was detected during the mashing, lautering, boiling, and fermentation steps of the brewing process. Overall, processing techniques used in this study caused various effects on the stability of phytochemicals.