This document specifies a method for determining the working life for adhesives mixed with hardener for load-bearing timber structures, by a viscosity test. This method is not suitable for determining the working life of a multi-component adhesive whose actual working life is very short. This document is only intended for obtaining a reliable basis for comparison between adhesives. The method gives results which cannot be applied to the safe manufacture of timber structures without modifications for the influences of factory temperature and relative air humidity.