Final answer:
It is true that excessive swirling of a spirit can be counter-productive because it increases the concentration of volatile alcohol, which may overpower delicate aromas during tasting.
Step-by-step explanation:
The statement that in tasting a spirit, full swirling is counter-productive, as it concentrates volatile alcohol that can compete with delicate aromas is true. When a spirit is swirled too vigorously, it can cause the alcohol to volatilize more rapidly, and its strong presence in the glass may overpower the more subtle aromatic compounds of the spirit. Professional tasters often prefer to swirl the spirit gently to allow the aromas to be released without being overwhelmed by the alcohol's volatility.