Related to the study of interactions between food and packaging, migration from agglomerated cork stoppers was studied by electron spin resonance. Paramagnetic probes were incorporated separately in the adhesive or in the cork granules. The finished cork was obtained by an individual molding procedure. The behavior of aminoxyl probes, differing by their functional groups, was studied. Free probes, initially incorporated into the adhesive phase, partitioned into cork during processing. Their migration occurred from both the cork and the adhesive phases. With amino-TEMPO, a probe covalently bonded to the adhesive phase, it was possible to study the penetration of the alcoholic simulant of wine (12% ethanol) into the whole structure of the cork and to demonstrate that strong swelling took place.