Rancio is a spanish term that describes the peak of refinement in aromas & flavours. After ageing cognac for many years, certain aromas reach their peak and cognacs with rancio qualities usually fetch a high price.
Below is the rancio chart for better illustration.
Note that rancio aromas do stack with age. Some cognac connoisseur will comment that the peak of cognac maturity ends at 50+ years. However this opinion may not be conclusive enough to cover all angles and the cognac exploration continues...
Some cognacs known for their rancio qualities are as follows:
