Whisky in Port Wine Casks


Port wine is the Portuguese version of sherry. It is made from grape juice, which is then fermented and fortified with brandy. Port wine, also called port for short, comes from the Douro Valley. Just like 'Scotch', Port is now a protected designation of origin. Every port wine therefore comes from Portugal.

Production and post-treatment

Port wine is made from fermented grape juice. However, there are differences between the different types of port wine. The biggest difference is in terms of sweetness or dryness, which is determined by the residual sugar content. Wines with low residual sugar content are called dry; those with high sugar content are called sweet.

The residual sugar content is determined in several ways. First, by the grapes used: a fully ripe grape has more sugar than an unripe one. Some grape varieties also contain more sugar than others. In addition, fermentation plays a role in the sugar content. The sugar from the grapes is converted into alcohol by yeast until all the sugar is used up or the yeast dies due to alcohol poisoning. To artificially achieve a higher residual sugar content, the fermentation process is stopped by adding brandy. The alcohol content increases, the yeast dies of alcohol poisoning and does not convert the remaining sugar into alcohol any further.

Effect on the taste

What happens when a whisky is matured in a port cask depends on the sweetness or dryness of the port previously contained. To be able to determine the effect the cask has on the whisky, you have to find out what kind of port was previously contained. Most ports tend to be sweet, so in principle one can assume that (post-)maturation in a port cask usually adds rather sweet and fruity flavours to the whisky.

Side note

Is port wine a 100% Portuguese product? No. Port wine only has to be produced in Portugal. This does not mean that all the raw materials have to come from Portugal. For example, much of the brandy used does not come from Portugal, but from developing countries, mainly in South America.

Effect on the colour

As with taste, the effect on whisky colour depends on the port. A very dry port has little effect on the colour of the whisky; a very sweet one, on the other hand, makes the whisky very dark. This is one way of determining whether a port cask contained sweet or dry wine. But one has to be careful when doing this. First of all, you have to make sure that the whisky is not artificially coloured. It is also important to know how long the whisky was allowed to mature in the port cask. If the whisky has been in the cask for more than five years and has not taken on a dark colour, it was almost certainly a dry port.