Ochratoxin A (OA), fumonisin B1(FB1) and fumonisin B2(FB2) were added to wort at levels of 0.19, 0.95 and 0.95μg/ml, respectively, and fermented for up to 8 days by three strains ofSaccharomyces cerevisiae.Decreases of OA in the beer over this period were estimated from straight line slopes to be 2–13%. Losses of FB1and FB2were estimated to be 3–28% and 9–17% respectively. Some OA was taken up by the yeast, up to 21% in a detailed study with one strain. In contrast, uptake of fumonisins by yeast was negligible (< 1% FB1and < 2% FB2). In control experiments, OA, FB1and FB2were found to be stable when added to yeast‐free wort and kept for up to 8 days at 25°C. In addition, spiking experiments with blank day 0–8 fermenting wort samples showed method recoveries averaging 87–91%. None of the mycotoxins was detected in control fermentations where they were not added to the wort.