(±)-Geosmin-(10-methyl-[d3]) is an isotopic standard of (±)-Geosmin. Geosmin (trans-1,10-dimethyl-trans-9-decalol) is a metabolite of various actinomycetes and fungi. It has been found to be responsible for an earthy taint in different foods like apple juice, cereals, fish, vegetables and wine. It has been found that geosmin in different French and Algerian wines and postulated flavour thresholds of 10 ng/L in water, 80-90 ng/L in a neutral red wine and 60-65 ng/L in a neutral white wine.