Caffeine, its primary metabolite (1,7-dimetylxanthine or paraxanthine) is a hydrophilic stimulant (log Kow < 0) that has been proven to be highly degraded and adsorbed during soil column experiments. In Mezquital Valley, caffeine and its metabolite are frequently detected in the soil but not in the underground water.

The bacterium first demethylated caffeine to 3,7-dimethylxanthine, and then mineralized the molecule. Caffeine was more stable in a silt loam soil than a sandy loam or loam soil, but biodegradation in all three soils was quite uniform upon the addition of caffeine-degrading bacteria or aerated biosolids.Several lines of evidence indicate that the mechanism of caffeine dissipation in soil is microbial biodegradation and it’s affected by temperature and moisture in the soil.