Wine will always be a fascinating subject to experience and once you delve into the chemical composition of the living substance you quickly learn that there are various ways the wine might have been made. It is at this point that you often go quiet and begin to realise how easy it is to rush in and offer opinions that may be way off target. Note I said “opinions” not fact, since this is often where the misconceptions originate.
Let’s take a look at Sauvignon Blanc as a single varietal. What we know about this grape is that it is full of personality and can behave in different ways; from shy and reticent to upfront, fruity and talkative. Sauvignon Blanc put into wood not only undergoes a name change, Blanc Fume, but transforms the wine into a seductive temptress. Did you know that Sauvignon Blanc, along with Cabernet Franc is the parent of Cabernet Sauvignon – the result of a spontaneous field crossing in Bordeaux in the 18th century. DNA profiling established this fact and this area of research continues to be critical where grape varieties are concerned.
Both these grape varieties show aromatic herbaceousness and this relates to the flavour compounds found in the varieties. These flavour compounds are called methoxypyrazines (let’s call them pyrazines) and the degree to which they show their herbaceous quality is directly linked to the micro-climate of the vine. Here’s how it works: cooler climate means less intense sunlight, which means less UV rays entering the canopy. Warm climates have more hours of sunlight and therefore more UV rays entering the canopy. The UV rays are responsible for burning off these pyrazines, thereby reducing the herbaceous character of the grape and therefore the wine. Think New Zealand Sauvignon Blanc and tasting notes read like this, “nettles, asparagus, tinned peas and cat’s pee”, whilst Sauvignon Blanc from South Africa shows more grassiness, limes, ripe-fruit.
Back to the pyrazines and what is also interesting is the stage of development of the bunches and individual berries. The decision to harvest these bunches is based on the ripeness of the berries and in particular the sugar ripeness, referred to as degree Balling. It is standard practice with Sauvignon Blanc to split the harvest in terms of sugar ripeness and to harvest say half the vineyard at 21 – 22 deg Balling and then the rest at 23 – 23.5 deg Balling. The result is a melange of flavours and acids. The grapes harvested earlier will show more pyrazine, herbaceous, higher acid levels, whilst those harvested later show fruity, upfront characters. The final product is balanced in terms of sugar, acid and fruit.
It is therefore apparent that winemaking is not just about what happens in the cellar, but the vineyard too and more importantly the behaviour of the berries as they relate to climate and environmental influences.