Sugar content of vintage port

[John Owlett]

My wife and I have recently moved into a house with a windowless underground cellar, which means that, for the first time in twenty-five years, we have suitable long-term storage for wine. Accordingly, my thoughts have turned to the Merlot-rich blends of the Bordeaux Right Bank, to the Grenache-rich blends of the South Rhône ... and of course to Port.

Unfortunately, nowadays I have to take diabetes into account. Are there any types of vintage port which consistently have less sugar than the average?

I have an (inexpertly formed) preference for the relatively dry style of Dow's port, so I am hoping that taste and health will point me in the same direction.

[Andy Velebil]

John,

Welcome to the site, we are glad you found us. As for your question, all ports stop the fermentation process when, approximately, the sugar levels fall by 1/2. This is not absolute as some houses are typically "dryer" than others. They achieve this dryer style by allowing fermentation to go just slightly longer, thus more sugar is consumed during fermentation.

Cockburn's ports tend to be a bit dryer and will have slightly less sugar. Here is a bit from their website,

When the sugar level falls roughly by half, grape spirit is added to kill the yeast and stop fermentation. The exact moment to stop the fermentation is one of the most critical aspects of port making. The fortification "window" is open for just a few hours. Cockburn’s ferments its must slightly longer than other port houses, using up more sugar and creating a less sweet style which is characteristic of all its ports. This style finishes with less sweetness, allowing more fruit flavor on the palate. The tannins also show through a little more, giving Cockburn’s ports their characteristic "grip."

How much lower is the sugar, I don't know. I wish I could give you more specifics. But others here may be able to help more.

[Frederick Blais]

Quinta do Infantado is one style that is really dry for a VP, they usually, on average the wine has 2% of degree in alcohol more than other houses before they stop the fermentation process.