W - like Whisky Solera
What does Solera or Solera System mean?
The solera system is a complex process that is used for the traditional ageing of sherry. The vast majority of sherries are matured in this system, which is also known as the "Criadera & Solera System". Incidentally, the word solera is derived from suelo, the Spanish word for soil.
Where can you see the Sherry Solera System?
The best place to buy them is directly on site in Andalusia, in one of the many warehouses of southern Spanish bodegas.
What actually is sherry?
Sherry is a white wine fortified ("fortified") with brandy, which is matured in oak barrels - usually made from American white oak, but also from European oak - or even in chestnut wood barrels. Sherry is a controlled designation of origin and is concentrated in a small region in Andalusia in southern Spain. Only nine towns have vineyards in their respective municipal districts that belong to the D.O. Jerez. These include the three towns of Jerez de la Frontera, El Puerto de Santa MarĂa and SanlĂșcar de Barrameda, which form the famous Sherry Triangle.
How does a Solera system work?
The solera system is a dynamic system consisting of several barrels. These are usually stacked on top of each other and often have a pyramid-like structure. The wine therefore not only matures in a single barrel, but - thanks to regular refilling from top to bottom in the barrel pyramid - passes through various stages in its maturation process, which consist of groups of barrels with increasingly older wine.
How is a Solera system structured?
The system generally consists of three or four rows of barrels stacked on top of each other, with each row representing a different stage of the ageing process. The bottom row, called the solera because of its proximity to the floor, is the last stage of the ageing system and contains the oldest sherry. Up to a third of the contents are removed from these barrels for bottling. The various criaderas are located in the rows of barrels above; the higher the row, the younger the wine that a criadera contains. The row immediately above the solera is the first criadera, and the wine in its barrels is younger than that of the solera. Above this row is the second criadera with an even younger wine, and so on. It is important to note that the individual barrels in a solera system are not connected to each other, but are simply stacked loosely next to and on top of each other.
Is the number of rows in the Solera system limited?
No. There can also be a third, fourth, fifth criadera or even more rows. There is no specific limit to the number of rows in the sherry solera system. However, if the solera system consists of more than three or four rows of barrels, the criaderas must be stacked in more than one pyramid to prevent the bottom row from bearing too much weight and, in the worst case, the solera barrels from bursting.
Why is there a whisky solera at St. Kilian?
Our Master Distillers ZoltĂĄn Fodi and Mario Rudolf's first trip to Andalusia in 2019, where they visited various wineries and cooperages, sparked their enthusiasm for sherry casks, Spanish bodegas and the Solera system. These fascinating impressions quickly gave rise to the idea of transferring the sophisticated and complex sherry solera system to the maturation of single malt whisky.
Which whisky solera is available at St. Kilian?
We have established two independent solera systems for maturing single malt whisky. In June 2020, we started with our Whisky Solera by St. Kilian mild, which was initially launched with cask-matured, non-smoky spirit. In October of the same year, we then launched the Whisky Solera by St. Kilian peated. This started with smoky, cask-matured spirit.
How is the mild whisky solera at St. Kilian structured?
The Whisky Solera by St. Kilian mild (unpeated) consists of three rows of seven casks each. The bottom row, the Solera, is made up of certified seasoned Pedro XimĂ©nez barrique casks (225 liters) from the Bodega XimĂ©nez-SpĂnola in the D.O. Jerez. Jerez. For the first criadera above, 225-liter medium sherry barrels, also from Bodega XimĂ©nez-Spinola, are used. For the top second criadera, we use certified seasoned first-fill Manzanilla hogsheads with a capacity of 250 liters.
Which casks is the smoky whisky solera made from?
As with the mild version, 225-liter certified seasoned Pedro XimĂ©nez barrique casks from Bodega XimĂ©nez-SpĂnola are used for the bottom row of our Solera peated whisky (six casks). The first criadera above this consists of two Amontillado Bodega 500 liter butts (each 20 years old) and a 500 liter, 30 year old Fino Bodega butt. Finally, three seasoned Oloroso butts (500 liters each) form the top row of barrels, the second criadera.
How was the Whisky Solera mild launched?
For the mild solera, a year-old spirit matured in charred (Char Level 4) 190-liter Virgin American Oak barrels was filled into the barrels of the second Criadera in June 2020. Its contents were then completely transferred to the barrels of Criadera one below in January 2021 and the empty barrels of Criadera two were refilled with two-year-old spirit matured in charred 190-liter Virgin American Oak barrels. One year later, in January 2022, we transferred the entire contents of the barrels of the first Criadera into the Solera barrels, transferred the entire contents of the second Criadera into the emptied barrels of Criadera one and refilled the empty barrels of Criadera two with now three-year-old single malt whisky from the charred 190-liter Virgin American Oak barrels.
How was the Whisky Solera peated started?
The principle is the same as for the mild whisky Solera. Only in October 2020, the casks of Criadera two were filled with one-year-old, smoky spirit matured in charred (Char Level 4) 190-liter Virgin American Oak casks. The refilling of the other cask series took place - as described above - in October 2021 and February 2023. Only for the refilling of Criadera two was a two-year-old, smoky spirit matured in ex-bourbon casks (Jack Daniel's) used from October 2021. In February 2023, the casks of Criadera two were then refilled with three-year-old single malt whisky matured in ex-bourbon casks (Jack Daniel's).
What's next for the Solera systems at St. Kilian?
From 2024, around 30% of the volume (around 400 liters) of the Whisky Solera mild will be removed from the Solera casks every spring and filled into our 0.5 liter pot still bottles. The missing volumes will be replenished from the rows of barrels above, as described above. The barrels of the top two criadera are then always filled with single malt whisky matured for at least three years in ex-bourbon barrels (Jack Daniel's). The same applies to the whisky Solera peated. Here, the first extraction from the Solera casks (approx. 30%) and bottling in 0.5 liter pot still bottles took place in autumn 2023. The subsequent bottlings will then always be released in the autumn of the respective year.
How do you calculate the age of a solera-matured whisky?
Given the nature of the Solera process, the age of a single malt whisky matured in it is inevitably expressed as an average and essentially corresponds to the rotation of the total stock in each maturation system. This average age depends on the number of rows of casks that make up the Solera system, the proportion of whisky that is removed from the Solera casks and the frequency of these removals. Provided that the system runs for at least three years so that the spirit can be called whisky, and that at least three-year-old whisky is always added to the Criadera two casks, the age of the Solera-matured single malt whisky is calculated as the quotient of the volume of all the casks in the Solera system divided by the volume withdrawn in one year. In 2032, our Solera whisky, whether mild or smoky, will reach an average age of 10 years.
How complex is this solera maturation process for whisky?
Maturing single malt whisky in our two Whisky Soleras by St. Kilian is extremely complex. It requires a lot of work and craftsmanship and also involves a great deal of effort. This is because it is not permitted in Germany to simply remove the required volumes from the casks using a pump. Due to German customs regulations, we have to empty each row of barrels completely, process each removed whisky using tax technology and only then are we allowed to put it back into the respective barrels. In other words, it is a very time-consuming procedure involving a lot of bureaucracy and documentation. But we are convinced that the quality of the whiskies and our success will prove us right.
Why is this enormous effort being made?
Because St. Kilian has always been known for innovation and experimentation. And because we are so passionate about sherry cask matured whisky and want to offer our customers and fans exceptional products. The Solera system will build up specific flavors that will add and enhance each other, resulting in an extremely complex and multi-layered single malt whisky to our liking. The exciting thing about this process is that our fans can follow and taste the development of the Whisky Solera by St. Kilian live every year with the corresponding mild and smoky bottlings.
Are there any other whiskies matured in the solera system?
Yes, there is at least one American distillery that matures one of its bourbon whiskies using the solera system. There are also Australian and Swedish single malt whiskies that are matured using this method.
Are other spirits or wines also matured in the Solera system?
But yes. For example, Spanish brandy, Brandy de Jerez, is also matured in the cascade-like process. There are also some rum distilleries that mature their sugar cane distillate in a solera system. Similar to sherry, the solera system is also used for some Malaga and Madeira as an alternative ageing method for these famous dessert wines. And high-quality wine vinegar is often also a product of this special ageing process.