Residual sugar in wine

On the advice of a merchant I bought (for me) a fairly expensive red wine, made in Australia’s Barossa Valley.

Looking at the back label, with its customary descriptive blurb of “berry fruits”, “plum”, “blackberries”, “chocolate”, “vanilla” and all the rest that someone thought up, I saw that the alcohol content was a stonking 14.5%.

In my view that is too high, with the alcohol overpowering those “berry fruits”. It was dry on the palate.

I took its residual sugar content. This was 8%, which should have made it a normally balanced wine. It was the tannin content that made it taste like a dry red wine.

Unaware of the tannin content, I had bought a wine that was happier to be more of a laying-down wine than one for present-day drinking. They might have mentioned this with the “berry” fruits business. Its tannins would have softened in time and brought the wine into balance, making it a fine wine.

It must have been very hot in the Barossa Valley that vintage year, with the grapes producing a lot of sugar. Even if the winemakers had stopped the fermentation earlier to reduce alcohol content, the resultant wine would have been too sweet on the palate. So 14.5% it was.

In Europe, we seldom get the very hot weather that produces too much sugar in the grapes. Here it is often the opposite, demanding added sugar to produce enough alcohol for pleasurable drinking and preservation.

I usually add sugar to my own vintages in London, aiming for around 22% before vinification (Port is about 20%), and fermenting the wine out to contain about 6% residual sugar.

I could stop fermentation of the sweetened must for the wine to contain more sweetness and less alcohol by adding sulphur, or even fine filtering (to get rid of the yeast) if I had the equipment. But I rather like to leave the whole process to nature.

As for the adding of sugar at fermentation time, French authorities, when I wrote professionally on wine anyway, designated that those winemakers below a certain latitude, were not allowed to add it. At that time, a pied noir, kicked out of Algeria, bought a vineyard in Bas Médoc, well south of the designated latitude, and  wondered why his wines were not as good as those made by his neighbours. That was, until he was woken at night by sugar tankers passing by to help improve those neighbour’s wines. He then started to make good wine.

Wine is often blended at source. I do as well, as my own red gets down to around 6% sugar. That is a bit too dry for it, so I have no compunction about mixing it in a decanter with a sweeter red – to the benefit of both.

Commercial winemaking is just another business where the weather is a major element and fortunes can be made or lost. So a certain amount of manipulation by the professional and the amateur when making wine is commonplace.

Dry whites and rosé wines usually have around 7% residual sugar content, reds anything between 6% to 9% - the successful results depending on body, tannin, sweetness and acidity. As for the wine’s acidity, this can also be added to wine, especially in hot climates, in order to produce a successful product.

Out of all this, it seems extraordinary to me that, combined with other factors, the differences between dryness and sweetness in table wines should depend upon such small differences (about 6%) in the wines’ residual sugar content.V