The whisky lover’s complete guide to sherry

When you first start to explore the world of single malt Scotch whisky, you learn early on that the vast majority of whisky is matured in two different types of casks:  Casks that previously held bourbon, and casks that previously held sherry. 

With further exploration and perhaps some self-education with your nose and palate, you’ll probably begin to be able to identify when a whisky’s maturation journey has been influenced by sherry casks.   In other words, you’ll either smell or taste the sherry cask influence on the spirit.  And, like many people, you might even find yourself favouring the sherried style of whisky, and you’ll have a preference for the distilleries that make sherry cask maturation a feature of their house style and portfolio.  (Glenfarclas, Glendronach, and Macallan arguably being the three main front-runners in this regard, although the Aberlour’s a’Bunadh release is also a long-time favourite).

Whilst many people understand and appreciate the concept of using second hand sherry casks to mature whisky, few people actually understand or appreciate sherry by and of itself.  What is sherry, as a drink?  What are the different types of sherry?  Do some sherry types work better with Scotch whisky than others?  If you’re one of the many whisky lovers who enjoys a sherried dram, Whisky & Wisdom presents this complete guide to sherry to help you understand more about what you’re actually enjoying and why…..

 

What is sherry?

Sherry is a wine, made from grapes.  Strictly speaking, courtesy of appellation control restrictions (aka protected designation of origin, aka Denomination of Origin), the term “sherry” officially denotes the drink as produced in the small region of Spain from which it originates.  (This is similar to why champagne can now only be used to describe the product made in the Champagne region of France, and the rest of the world now has to call their version of it sparkling wine.  In Australia, a country which has a long history of producing sherry, the locally-made product is now known as apera.  Canada has also adopted the term apera).   

Originating in the city of Jerez de Frontera in the province of Cadiz, but often simply referred to as the Jerez region, the word sherry is actually the anglicised form of Jerez.  It’s a bit like whisky being the anglicised form of uisge beatha.    

Made predominantly from palomino grapes, sherry is a fortified wine, meaning that it has distilled spirit added to it to increase the wine’s alcoholic strength.   The grape spirit is added after fermentation, and the liquid is then aged in oak casks.

 

What’s unique about sherry?

Sherry is, initially at least, a dry wine, as the grape spirit is added after fermentation, meaning all of the sugars in the grape juice (referred to as must) have converted into alcohol.  This is in contrast to port, where the spirit is added halfway through fermentation.  (In port production, fortifying with spirit halfway through arrests the fermentation process, thus leaving a portion of the sugars behind and resulting in a sweet drink).

Different types and styles of sherry are produced by manipulating the must, the amount of fortifying spirit added, and the aging process and methodology. 

 

What are the different types of sherry, and how do they relate to the whiskies we enjoy?

The different types of sherry – most of which you’ll encounter in the Scotch whisky industry – are fino, manzanilla, amontillado, palo cortado, oloroso, moscatel, and pedro ximenez.  All but the last two are typically made from the palomino grape; moscatel and pedro ximenez (often denoted PX) are named after the grapes from which they’re made. Let’s look at each sherry in order from driest to sweetest and see where they fit in the world of whisky….

 

Fino & Manzanilla

When the grapes are processed to produce the must, at least two pressings are carried out.   Must from the first pressing will be used to make both Fino and Manzanilla.  (And also Amontillado, but we’ll get to that in a moment).

Once the fermentation is complete, the wine will be sitting at around 11% ABV or so.  The wine is then fortified by adding grape spirit (essentially a brandy), increasing the alcohol content up to around 15-16% ABV.  The fortified wine is then filled into casks, leaving space or a gap at the top.  A natural film or “cap” of yeast will subsequently form on the surface at the top, known as flor.  This layer of yeast serves to seal or protect the liquid underneath it from contact with the air, and thus prevents oxidation.        

The wine will typically be aged in a solera system for a minimum of two years, although ageing for up to ten years is not uncommon.   Fino & Manzanilla are produced in much the same way, however, Manzanilla is protected by Denomination of Origin and can only be produced in the town of Sanlúcar de Barrameda. Manzanilla is a lighter style, and its coastal location imparts a light salty or maritime character to it – much in the same way we associate a brininess or maritime character with the coastal or island Scottish distilleries.

Contrary to a common misconception in the whisky community, the majority of sherry – and particularly Fino – is aged in American oak, and not Spanish oak.   Ex-Fino casks are frequently used in the Scotch industry, and plenty of distilleries have put out releases that were either wholly matured or finished in ex-Fino casks.  Laphroaig, Tomatin, Tobermory, and Kilchoman have all had recent examples.

 

Amontillado

Amontillado effectively starts life out as a Fino and is initially aged under flor.  The yeast is then allowed to die off, or is deliberately killed by adding more fortifying spirit to take the ABV up to around 17-17.5%.  The wine is then allowed to continue aging, but will now have contact with the head of air in the cask, and thus will age with oxidation.   It will thus begin to take on more colour, and will also develop more complex, richer flavours.

Ex-Amontillado casks again feature in the Scotch whisky industry – the Glenkinchie Distillers Edition is perhaps the best known.

 

Palo Cortado

Palo Cortado is relatively rare and makes a virtue of an unintended accident.  The wine is originally intended and prepared as a Fino or Amontillado.  At some point down the track, the flor inadvertently breaks down or dies undetected, and the wine starts to age with oxidation.  If this is then subsequently discovered, the winemaker adds additional fortifying spirit to increase the ABV to around 17.5%, in order to prevent the wine from spoiling.  It is then allowed to continue aging oxidatively.  The final result is a sherry that combines some of the yeasty crispness of Fino with the richness of Oloroso. It’s estimated that only 1-2% of Finos & Amontillados experience the unintended breakdown of the flor, and thus it’s perhaps the one style of sherry you won’t hear much about in the Scotch industry, owing to its rarity.

 

Oloroso

Oloroso is produced from the must obtained from the second pressing.  When the initial fortifying spirit is added, the ABV is taken straight to a higher amount of at least 17%, which both (i) prevents the yeast flor from forming, and (ii) prevents the wine from spoiling.  It is thus aged under oxidation, and will usually be aged through the solera system for between five and 25 years, resulting in a darker liquid that is particularly rich, spicy, and nutty.  Again, contrary to common whisky folklore, Oloroso sherries are still dry.  As a result of the maturation process, climate, and natural evaporation of water over the longer time period, Olorosos can occasionally be bottled at higher ABV’s of around 20-22%.

Oloroso is seemingly the most common sherry style of choice for the Scotch whisky industry. Macallan evidently carried out a series of taste trials in the early 1970’s and determined that ex-Oloroso casks worked best with their spirit; this laid the foundation for the releases and the reputation the distillery established in the 1980’s and 90’s.

 

Moscatel

Made from Moscatel grapes, Moscatel sherries are made in the same way as port, that is, the fermentation is cut short by adding fortifying spirit before fermentation is complete – thereby leaving residual sugars behind and producing a particularly sweet liquid.  (Pedro Ximenez, as outlined below, is also made this way).   Some Moscatels are also produced by first sunning the grapes – a process that evaporates some of the water and increases the sugar concentration.   Sunning the grapes – a process known as asoleo – is a feature of Pedro Ximenez production.

Arran, Tomatin, and Glenallachie have released Moscatel-matured or finished whiskies in recent years, although the front-runner and consistent player in this regard is the Caol Ila Distillers Edition.

 

Pedro Ximenez

Made from Pedro Ximenez grapes, rather than palomino, the grapes are first dried in the sun to concentrate the sweetness – the asoleo process.  The grapes can take on a raisin-like appearance, and a short fermentation delivers a dark, extremely sweet, raisin-tasting liquid that is then fortified with grape spirit and aged oxidatively.  The resulting sherry is a rich, unctuous, syrupy, dessert wine.  

How sweet is sweet?  Well, even the dry sherries might still have a tiny smidgeon of residual sugar in the bottled product, measured in terms of grams per litre.  Fino and Amontillado might have anywhere between zero and five grams of sugar per litre.  In contrast, Pedro Ximenez will typically have a minimum of 200g per litre.  For comparison, a typical port will contain around 100g/L.

Not surprisingly, PX casks have great appeal in the whisky industry, as the flavours from the cask influence, together with the natural wood sugars, can impart sweetness to the maturing whisky.  Lagavulin was the front-runner in this field, with the Lagavulin Distillers Edition the first commercial release to make a virtue of PX-finishing in the mid-1990’s.   Laphroaig has also put out a PX release, whilst Glendronach has had a field day releasing a long line of PX single cask releases.

 

What about sweet sherries and cream sherries?

Cream sherries are the “blended whiskies” of the sherry world, in that different sherries are blended to create a particular flavour profile.  Almost invariably, the dry sherries are “sweetened up” by being blended with Pedro Ximenez or, occasionally, other sweet wines.  Depending on the wines used and the resulting level of sweetness, these sherries fall into three designations:  Pale Cream, Medium, and Cream.  Pale Cream achieves a balance between the dry bitterness of Fino and some sweetness; Medium will have sugar contents of between 5-115 grams per litre; and Cream is typically a blend of Oloroso and Pedro Ximenez. 

 

The use of sherry casks in the Scotch industry

As discussed above, sherry is typically aged in a solera system, meaning that – generally speaking – the casks are in continuous use and part of a perpetual process of being partially emptied and partially filled as the sherry makes it way through the solera.   Such casks are not the ones employed in the Scotch industry!      

Traditionally, it was the transport casks that found their way to Scotland and were used to mature whisky.  In the days when sherry was a popular and heavily consumed drink in the UK, the wine was filled into casks and shipped in bulk to the UK.   Instead of the casks being returned to Spain once they’d been emptied, they were nabbed by the Scottish distilleries who then put them to good use. 

The days of shipping sherry in casks to the UK in bulk have long gone, due chiefly to Spain introducing new production laws in the 1980s that require the wine to be bottled in its country of origin.   This, coupled with a worldwide decline in sherry’s popularity and consumption, means that the Scotch industry now has to take matters into its own hands to source sherry casks.

The distillers now commission the bodegas in Spain to produce sherry specifically for the purpose of “seasoning” the casks.  The casks will typically be filled with must and given three months’ primary fermentation.  They’ll then be filled with maturing sherry (e.g. fino or oloroso) and typically seasoned for two to three years with the wine before being sent to Scotland to be filled with new-make spirit.  The seasoning wine emptied from the cask will either be distilled; go towards vinegar production; or – according to some whispers in the industry – simply  get tipped down the drain.

The distilleries therefore tailor or specify the sherry casks they seek for their production.  They’ll specify either American or European oak, and the type of sherry to be used for the seasoning.  Distilleries obviously form business relationships with specific bodegas and producers or, in some instances, the whisky company actually has a financial interest in or part-ownership of the bodega to secure their sherry cask requirements.   The universal constant in the industry is that sherry remains a waning and unpopular drink (certainly compared to its heyday in the mid-20^th century), and so production levels are down.   Making sherry purely for the purposes of seasoning a cask and then having to process or discard the unwanted wine – for which there’s no market – is an expensive exercise, and so sherry casks carry a huge premium.  From figures prepared by the Scotch Whisky Industry Review in 2019…..

• A refill bourbon hogshead^# has a price tag of around £50.
• A 1^st fill bourbon hogshead costs around £200.
• A 1^st fill sherry hogshead costs around £250.
• A 1^st fill sherry butt costs around £500.

^# The figures above have been normalised for a hogshead, but it’s worth noting that the practice of re-coopering ex-bourbon barrels into hogsheads by inserting additional staves, effectively increasing their capacity from 200 litres to 250 litres, is generally in decline.   An increasing number of distillers are choosing to keep the 200 litre barrels intact, but now fill them at a higher filling strength, rather than water them down to the traditional filling strength of 63.5% ABV.   In an illustration of the complex nature of market forces, this is essentially a fallout of the USA’s housing crash in 2007, which had flow-on effects to the American lumber industry and caused a shortage of bourbon casks and a corresponding price increase spike of 200% for bourbon casks in 2015!

Note also that the above figures perpetuate the oft-quoted “fact” that an ex-sherry cask costs ten times that of an ex-bourbon cask, but it’s rarely understood or appreciated that the ten-times multiplier is unfairly comparing a 250 litre used cask with a 500 litre new cask.  And that’s before we get into the price variations associated with European oak versus American oak, economies of scale, etc.  Furthermore, it’s worth noting that the market changes quickly – the figures above were the predicted figures for 2020, forecast and published in 2019… and yet a well-known Speyside distillery contacted for this article advised they are currently paying around £650 for a 1st fill sherry hogshead and £1,200 for a butt!  1st fill bourbon barrels currently command around £250.

It is for these reasons that sherry-cask-matured whiskies generally carry a price premium and are the more expensive bottlings on the market.   Some might also suggest that scarcity and cost is one of the reasons why sherry casks are increasingly being used for finishes, rather than full-term maturation.

 

The impact of sherry casks on flavour

As a very general comment and guideline, sherry casks typically impart aromas and flavours of dried fruits, spices, and tannin to whisky.  “Christmas pudding in a glass” is an oft-used descriptor, and it reflects the general characteristics of sultanas, raisins, glace cherries, currants, dried figs, dates, prunes, plums, and so on.   Such notes are all the more prevalent when the sherry casks are European oak (quercus robur, or occasionally quercus pyrenaica, aka Spanish oak), as opposed to American oak (quercus alba).   European oak is less dense than American oak, and so the spirit has more interaction with the wood, which drives enhanced extraction and the more pronounced woody/oak notes. 

In contrast to this, whisky matured in ex-bourbon casks will lean more towards notes of vanilla/caramel, citrus, coconut, and some tropical or orchard fruits.

The other consideration to bear in mind when discussing the use of sherry casks in the Scotch whisky industry is the issue of sulphur.  That’s a whole other topic that deserves its own article or chapter, but for a clear and simple account of sherry casks and sulphur, you can read Whisky and Wisdom’s short piece on the topic here. 

In the meantime, the next time you pour yourself a sherried dram…you’ll now have a better understanding of the sherry industry and the work that took place in Spain before our friends in Scotland did their part to produce a delicious drop.

Cheers,
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PS: For further reading on some of the more popular “sherried whiskies”, you might also like:

• Glenfarclas 105 versus Aberlour a’Bunadh
• The highs and lows of Macallan
• What makes a whisky a “Christmas whisky”
• Glendronach vs Glenfarclas vs Macallan

PPS:  If you enjoyed this article, you might also like our other “explainer” articles:

The complete guide to peat and peated whisky

The complete guide to non chill-filtered whisky

The complete guide to oak, casks, & whisky maturation

The 1980’s heavy metal guide to whisky

Oxidation – does whisky go off in the bottle?

Corked whisky – fact or myth?

The stink about sulphur