Does whisky taste better the older it is? According to a team of Japanese scientists led by K. Koga it does, and it's better for your health too. And it's all down to the wood.
Oak contains the compounds known as lignins and tannins. Maturing is known by the less attractive technical name of 'ethanolysis' - the degradation by ethanol. This results in the release of the oak compounds from the barrel. The non volatile components are mainly minerals, sugars derived from cellulose and hemicellulose, but one of the main components are polyphenols: ellagic acid and gallic acid originate from the tannin, and lyoniresinol from lignin. They are responsible for the fragrance and taste - as well as the coagulation of ethanol and water in natural single malt whisky - and are often compromised in the process of chill-filtration. They are also antioxidants.
Ethanol, the main component of whisky, is perceived by the stimulating of the sweet and bitter taste receptor cells and the stimulation of the epidermal mucuous membrane in the mouth. This happens through the denaturation of proteins and is transmitted to the brain via the trigeminal nerve. Excessive stimulation is now believed to lead to the formation of radical oxygen scavenging activity - which is good news, not an underground political movement.
Reactive oxygen species (ROS) are very small molecules which are highly reactive. They are formed as a natural byproduct of the normal metabolism of oxygen and have an important role within our body's cells. ROS must be continually removed from cells to maintain healthy metabolic function or in certain conditions ROS levels can increase dramatically. The ROS need to be scavenged, and this is where antioxidants come in to play:
Polyphenols are Antioxidants. They are compounds that protect cells against the damaging effects of ROS. An imbalance between antioxidants and ROS results in Oxidative Stress, which leads to cellular damage linked to cancer, aging, Parkinson's and Alzheimer's, cardiovascular disease and cataracts. Antioxidant polyphenols 'scavenge' the radical oxygen providing protection against these diseases by contributing to the total antioxidant defense system of the human body. Vegetables, red wine, chocolate, green tea, olive oil, bee pollen and many grains are alternative sources.
But these cunning Japanese scientists have proven that the three polyphenolic compounds extracted from the oak casks are found in increasing volumes with age. Between a 10 year old single malt whisky and a 25 year old version of the same type the polyphenol antioxidants increased three times (lyoniresinol) to eight times (gallic acid).
Clearly, If you want to prevent yourself from going doolalli, drink the oldest single malt you can find. Or, drink young whisky that has been aged in top quality, fresh oak.