SERS evolution recorded over a drop‐coated coffee‐ring pattern of citrate‐capped gold colloids was investigated as a function of time under low‐specific laser power. Spectral changes caused by plasmon‐induced reaction could not be detected, but a long‐term transient original spectral profile showing additional lines was observed. We performed deep qualitative and quantitative SERS intensity variation analysis based on the complementary use of extreme deviation and cross‐correlation statistics, which provided further insights on the behavior of citrate‐capping layers of gold nanoparticles upon laser illumination. More precisely, the cross‐correlation analysis made possible to follow the so‐called individual events denoting particular resonance structures, in which groups of modes were assigned to an evolution of citrate coordination on gold surface driven by photo‐activation. As a consequence, the detection limit was increased and new lines were related to the presence of a very low amount of dicarboxy‐acetone (DCA), which was already present in the system.