Sherry cask whisky vs Port cask whisky

The key differences at a glance

Geography

Sherry must be produced using grapes grown in the Sherry triangle in Spain, a region between the towns of Jerez de la Frontera, Sanlucar de Barameda and El Puerto de Santa Maria (and a handful of other villages on the outskirts.)

Port must be produced from grapes grown in the Douro region in Northern Portugal.

Grapes

Sherry can be produced from 3 white grape varietals, namely Palomino, Moscatel and Pedro Ximenez

Port can be produced from over 100 grape varietals, the 5 most famous are Touriga Franca, Tinta Roriz, Touriga Nacional, Tinta Barroca and Tinta Cao. Both red and white grapes can be used.

Ageing

Sherry must spend a minimum of two years in oak. It can be aged oxidatively or biologically. Biological ageing locks the wine under a flor (a natural yeast layer) ensuring the wine stays crisp, dry and light in colour. Oxidatively aged Sherry is exposed to air and turns dark quickly due to interaction with oak and the air.

Port is aged in oak vats up to 200,000L, Port hogsheads (250L), Port pipes (500L), stainless steel tanks, bottles or a combination of these methods. It tends to be oxidatively aged allowing the colour to deepen over time during maturation. However, the largest category of Port on the market rarely sees oak casks, often maturing in huge stainless steel or wooden vats. This means Port casks are much less abundant than their Sherry counterparts.

Fortification

Sherry is almost always fermented dry before fortification. Fino, Amontillado, Palo Cortado and Oloroso are all bone-dry wines. Pedro Ximenez is an exception due to the high sugar content in the grapes.

Port is usually fortified before the wine has fully fermented. This leaves residual sugars that ensure a sweetness on the palate vs the Sherry wines from Spain.

How sherry and port casks create different flavour profiles

The flavour profiles given to a whisky by Sherry and Port casks are influenced by two things: oak type and wine type. We'll look at these shortly, but let's have a look at the classic flavour profiles first.

The Sherry cask flavour signature

When the type of Sherry is not specified on a whisky label, it is safe to assume that the casks have been seasoned with Oloroso style wine. The vast majority of Oloroso style wine produced is made for seasoning casks for the whisky industry, such is the popularity of the Sherry cask. The wine is often 17-19% alcohol and acts like a sponge, removing unwanted harsh and bitter oak notes from the cask. The flavour the wine leaves behind is minimal. The flavour we are actually enjoying in a Sherry cask whisky is a richness derived from the oak. It tastes like Sherry, because the Sherry absorbs the same oak notes during it's early fermentation in oak in Spain. Expect nutty flavours, Christmas cake, dried fruits, orange peel and chocolate.

The Port cask flavour signature

Port is a much sweeter wine, due to the early arresting of fermentation. The residual sugar and viscosity leaves a noticeable mark on the inside of the cask. The result is sweeter notes from the wine impacting the whisky. These notes include Christmas cake, berry jam, white chocolate and soft red fruits. The majority of casks used in the whisky industry from Portugal are Tawny casks.

Why the sub-style of wine matters more than the cask label

Even though Oloroso and Tawny casks represent the majority of Sherry and Port casks in the whisky industry, there are other types of wine that influence the flavour of the whisky in the cask. So let's compare what each wine type brings to the party.

Oloroso vs PX: two very different Sherried whiskies

Oloroso is a dry Sherry style. It removes flavour from the oak, acting like a sponge. It's main job is the removal of bitter and astringent flavours and aromas from the oak. This means the whisky picks up dried fruit or kitchen spice notes whether the cask is made from Spanish or American oak. Vanilla, orange citrus and caramel notes are also associated with Oloroso casks.

Pedro Ximenez on the other hand is a rich, sweet wine of over 212g/L sugar. The wine. coats the inside of the cask, so when the whisky enters this environment, it will undoubtedly pick up some aromas and flavours from the wine. Dark chocolate, treacle, raisins and dark caramel notes are all hallmarks of a whisky matured in a PX cask.

Ruby vs Tawny: two very different Port-matured whiskies

Ruby Port is known for it's fresh, vibrant and fruity flavour. It is aged in sealed tanks and therefore spends very little time in oak. If a Ruby Port does spend time in oak casks, this time will be minimal. The result for a whisky will be the transfer of vibrant, berry fruits and white chocolate.

Tawny Port spends much longer in oak casks. Ageing oxidatively, it is closer to a Sherry in style, probably somewhere between a PX and an Oloroso. Drinkers can expect notes of Christmas cake, kitchen spices and toasted oak.

Full maturation vs cask finish: how contact time shifts the balance

As with most things in the world of whisky flavour creation, time is crucial. The longer a whisky is in contact with an oak cask, the more flavour the cask imparts on the spirit. Therefore, we can assume (correctly) that full maturation in a specific cask type will be different to a finish over a period of months or a couple of years. But, that is not to say that full maturation is always better than a cask finish.

Example 1: Whisky matured in an Oloroso seasoned cask for 12 years

An Oloroso cask these days is generally a Spanish virgin oak cask that has been in contact with Oloroso Sherry for 2-3 years. The oak has a lot of colour and flavour to give, the wine as explained above, has less of an impact. Maturing the whisky in here for 12 years allows the spirit to absorb wood flavour, natural colour and texture and then integrate and shape it over years. A simple finish might give the whisky a hit of colour and dried fruit richness, but a full maturation allows tannins to soften, flavours to develop and a complexity in the richness to develop. This is how The Macallan is matured.

Example 2: Whisky finished in a Pedro Ximenez seasoned cask for 2 years

A Pedro Ximenez cask is a different prospect. The wine often stays in cask for closer to 5 years for seasoning, leaving much more flavour behind. This flavour is rich, chocolatey and decadent. The oak these casks are made from is just as active as the oak used for an Oloroso cask, but the high sugar content acts like a barrier, leaving more of the astringent and undesirable compounds in the wood. Despite the heightened sweetness, there is a danger that a new make spirit can be overpowered by the oak and the wine leaving a challenging flavour profile behind. There are two ways to combat this. One is to mature a robust new make spirit in these casks, knowing it can match the intensity. This is what Glendronach do. The other is to use a base whisky with a bit of sweetness already and finish the whisky. Dunville's have become masters at this approach.

Example 3: Whisky finished in a Tawny Port cask for 2 years

A Tawny Port cask brings a bit of sweetness from the sugar content, and a bit of fruit from the wine. The casks themselves are older than those used for Sherry. This results in less oak influence from a Tawny Port cask. For a full whisky maturation, there would be a lovely injection of Port flavour and colour, but less oak structure compared to an Oloroso Sherry cask. Therefore, many distilleries will choose to finish in Tawny Port casks.

Example 4: Whisky finished in a Ruby Port cask for 6 months

Ruby Port does not spend much time in oak. This preserves it's vibrant and fruity flavour profile. Therefore, any ex-Ruby Port casks tend to have lots of oak influence to give, and very little wine influence sitting on top. These casks need to be watched very carefully as they can overpower the desired fruity wine effect overnight. A full maturation in these casks would almost certainly negate any influence from the wine so Whiskymakers tend to treat them with exceptional care.

The oak variable most people overlook

So far we have spoken almost exclusively about the wine, but there is a much more important factor when it comes to flavour from a fortified wine seasoned cask, and that is the origin of the oak. Whisky casks made from Spanish oak will have a different flavour profile than whisky casks made from American oak or whisky casks made from French oak.

American oak

American oak is the most abundant oak type used for making Port casks and Sherry casks these days. Grown in the Eastern Seaboard of the USA, this oak is transported to the cooperages in Spain for making both fortified wine casks and whisky casks. It has a high vanillin content, low tannins and is the best type of oak for maturing wine due to it's lighter touch on the wine during fermentation and maturation. However, it is not the type of oak we need to create the Sherry bomb whiskies we know and love.

Spanish oak

Spanish oak is grown in the forests of the North of Spain. It has 5x more tannin than it's American cousin, meaning the natural colour derived from these casks tends to be darker and richer. When we see a very dark Sherry cask whisky, it has most likely been matured in a Spanish oak cask.

French oak

French oak sits between American oak and Spanish oak. It delivers the ginger notes expected from American oak and the Christmas cake notes expected from Spanish oak. It will also deliver a colour spectrum that is higher than American oak, but lower than it's Spanish cousin.

Check out The Whisky Club's guide to casks for an even deeper dive.

Why sherried whisky costs more (and whether it's worth it)

Sherry casked whiskies are more expensive simply because Sherry casks themselves are more expensive. When a distillery wants an ex-Bourbon cask, an ex-Rum cask, ex-wine cask or an ex-Port cask, they are buying a second hand vessel that has passed its useful life in another industry. When they are buying a Sherry cask, they need to get one built from scratch OR snaffle one of the very few decades old Bodega casks that appear on the market. Here is a rough life cycle of a Sherry cask used for making Tamdhu:

Today

A tree is felled in a forest in the north of Spain. The log sits in situ drying out to remove moisture and tannin. Chemical breakdown starts to make the flavour compounds more complex. This process takes 1 year.

1 year from now

The log is cut into staves in the north and transported to a cooperage in Jerez de la Frontera. These staves are left for a further 2 years to dry out further. The chemical breakdown continues.

3 years from now

The staves are selected for moisture content where they are shaped into 250 or 500L casks for the seasoning process. They are toasted, charred and tested. They are then filled with Oloroso wine that is at least 2 years old. These casks are seasoned for 2-3 years.

5 years from now

The casks are shipped whole to Tamdhu distillery where they will be filled with new make spirit. This matures into the Tamdhu we know and love. The wine will be used to season the next batch of casks.

Which style suits your palate

We find that both Port and Sherry casked whiskies have different places in our whisky drinking habits. If you are sitting in front of a roaring fire feeling traditional, then a Sherry bomb from a Sherry butt will scratch that itch. Meanwhile, if sharing a dram by the water in summertime by a bonfire, a Port cask whisky's brightness and vibrancy makes us smile.

Matching with food is great fun. Whiskies from both Oloroso and Tawny casks carry a nutty flavour profile. But the sweetness in the Port tip us towards a chocolatey dessert whereas a Sherried whisky cuts nicely through blue cheese, and a Pedro Ximenez finished whisky is perfect with vanilla ice cream.

Try both styles with The Whisky Club

Here at the Whisky Club we scour the world for whisky matured in both Port and Sherry casks. Whether a single cask finished in PX , a full maturation in Oloroso Sherry casks or a Tawny Port finished coastal dram, you'll find exclusive fortified wine finished Scotch whisky here at The Whisky Club.

Join today for access.

Do sherry cask whiskies always taste sweet?

Most Sherry cask whisky presents as sweet, usually due to the work of the Whiskymaker or Master Blender. Pero Ximenez casks present notes of dark chocolate and raisins, whereas Oloroso casks showcase aromas of dried fruit and baking spices.

Can a whisky be matured in both sherry and port casks?

Yes, marrying both styles of cask together is possible. Glendronach and Benriach have both produced whiskies in the past that utilise Port and Sherry casks together.

What does "sherry seasoned" mean on a whisky label?

Sherry seasoned simply means that a cask has been coopered from new oak and then filled with wine for a few years to prepare it for maturing whisky. The wine will extract undesirable flavours from the wood and may leave some flavour behind. All Sherry casks are effectivelt Sherry seasoned.

Are port cask whiskies less common than sherry cask whiskies?

Port cask whiskies are less common simply because Port casks are less common. The Sherry cask industry involves seasoning new casks with Sherry wine for the sole purpose of maturing Scotch whisky. The volume of seasoning wine far outweighs the volume of wine produced for drinking these days. Port casks on the other hand are vessels that have fulfilled their time in the Port industry, and only become available in small parcels.

Is one cask type objectively better than the other?

No. From a flavour perspective, each cask brings its own unique style and complexity to a whisky, and will be enjoyed during different drinking occassions and by different palates. From a craft perspective, both are coopered to last for many decades, and designed with the final contents in mind. So a Port pipe being coopered for holding Tawny Port for decades might have different specifications than a Sherry butt being designed for holding Scotch whisky for many decades, but the craft of the cooper is no less impressive.

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