Talk of time and tannins 27 December 2006

Martin Moore takes pleasure in the seasons and also gets a bit technical about phenols

In a world where everything is constantly changing there is something enormously comforting about the annual cycle of life when, as regular as clockwork, on a clear and beautiful spring morning, you suddenly notice the tenderest of green shoots sprouting out of seemingly desiccated vines.

This year was no exception. By the time you read this, we'll be seeing the last bunches flowering while in the case of the early cultivars, the berries already vary in size from match stick heads to peas. By the end of December colour blushes will start showing on the early red varietals. On our producer farms non-bearing side shoots are being carefully removed to create an environment of filtered sunlight, thus providing optimum working conditions for the enzymes in the berries that produce the intensity of colour, the tannins and flavours.

When discussing tannins we usually do so in the context of wine and the astringency it imparts to it, and we seldom ask ourselves but why is it present in the grape in the first place? (It is, of course, not unique to grapes, but is found in many fruits as well as in the bark of trees.). Like everything else, tannins are an integral part of the wonderful workings of the world around us.

Tannins for protection
As everything else in nature, vines have but one purpose, to propagate the species by dispersing its seeds as widely and as far as possible. That is, at the right time, when the seeds are ripe and able to germinate. Until that point is reached, the vine protects its fruit by producing tannin that makes it bitter to the taste. Once the pips are ripe, the situation changes completely: now the sugar accumulates, the acidity drops and the berries display their full colour and flavour to attract birds and animals. However, despite being ripe, the pips stay bitter and high in tannin to discourage animals from chewing them so that they will pass through the digestive system unscathed.

To be a little more technical for a moment: tannins are bitter or astringent plant phenols that occur naturally in the skins, pips and the stems of grapes. These natural antioxidants produce an almost leathery, dry feeling in the mouth. (This sensation is not surprising - tannins' ability to interact with proteins forms the basis of the process used for the tanning of animal skins, hence also the name.)

Tannin in wine binds with itself, proteins, sugars and the red colouring agent in wine called anthocyanin. In time it becomes less astringent and contributes to a wine's pleasant sensations like body, balance, structure, roundness and length. As winemakers we do our utmost to extract the tannins that form the backbone of our red wines in the softest possible way by soaking them out rather than by mechanical means. (Compare a cup of tea made by proper soaking against a cup where the teabag has been mauled with a teaspoon and you will understand why we take so much care.)

If you experience astringency more strongly than some of your fellow drinkers, you are probably one of those people with up to four times more protein in their saliva than others. (And if you want to debate whether birds have saliva I must remind you of the Asian delicacy called birds' nest soup that is made from the dried saliva collected from birds' nests. A tannic red will probably be just right to accompany  it!)

Ten weeks from harvest time
Judging by what is happening in the vineyards I would say we are about 10 weeks away from the start of the 2007 harvest. With that observation my internal clock has also started ticking, telling me I should be preparing myself for that event by slowly drifting off into rest mode for the holiday season to build up a burst of energy when the first grapes hit the crusher.

As you know from your own experience we have very little control over this internal mechanism known as the Circadian clock lodged somewhere in the brain. Following the cycle dictated by this clock, ancient man gathered food during the day and rested at night, when the darkness sent a signal to the pineal gland at the base of the brain to release a stream of melatonin into the bloodstream that made ancient man pull up his headrest. I am not particularly fond of melatonin, especially not by the glass. I find that during the holidays some Sauvignon Blanc at lunchtime is all I need to induce an afternoon nap - and spark off a craving for an early-evening barbeque, when a good Merlot painlessly replaces the SB.

Just the opposite happens during harvest time when the brain now sends a very different message to the body which, deprived of wine, rouses itself mightily to work around the clock (pun intended) and banish sleep until April!

• This contribution is extracted, with permision, from the Durbanville Hills December newsletter. Click here for the Durbanville Hills website.