The Solera process at St Kilian
explained in detail
At the beginning of November 2023, the St Kilian Distillery
introduced
a new seated single malt whisky
which has matured in an Andalusian Sistema Solera.
It is probably one of the first peated single malt whiskies in the world
which matured totally in Spanish Sherry casks
by applying Criadera Solera methods.
Translated by WIX from German
Ernie Scheiner
thanks to St Kilian's CTO Mario Rudolf for the interview
as well as the transparent explanation of the St Kilian Solera
A Sherry type of Solera at St. Kilian Distillery, what is it like?
The master mind of St Kilian is Mario Rudolf. The qualified master brewer developed into one of the most innovative German whisky makers at the St Kilian distillery. The conditions were favourable. Andreas Thümmler promoted and supported the creative perspectives of his CTO Rudolf. The Rüdenau CEO is enthusiastic about the tremendous development of his family-run distillery near Miltenberg am Main. The wide-ranging St Kilian portfolio delights the local whisky collector.
An encounter with the Irish distillation expert David F. Hynes - Cooley, Kilbeggan, Great Northern - developed into a friendship that ultimately led to the founding of the St Kilian distillery in 2012. The first barley distillate bubbled through the Spirit Safe in 2016.
Mario Rudolf, who comes from the nearby town of Amorbach, learned fast from Scottish and Irish distillery colleagues and winemakers in Andalusia. The former head brewer and malster was impressed by their wines and production methods in Montilla, Málaga and Jerez. Personal contacts with renowned cooperages and bodegas enabled him to create new, direct ways of maturing whisky in first-class containers at St Kilian. In addition to 103-year-old Vino de Color Barriles from the Bodega Herederos de Argüeso are barrel cultures from the most famous bodegas in the D.O. Jerez, D.O. Malaga and D.O. Montilla Morilles.
"Our New Make also feels particularly at home in sherry casks and generates a complex aroma profile in them that really convinces me,"
whisky blender Rudolf says.
Why shouldn't we use the Andalusian sherry-solera system when maturing the St. Kilian malt whiskey,"
the Franconian thought.
Together with the head distiller Zoltan Fodi - also a participant of the seminar in Andalusia - he discussed processes of adaptation and possible ways of implementing the solera method at St Kilian. The way was difficult because vinologists were unable to provide any help from Andalusia for their initial construction of a whisky solera.
The first difficulty was the actual procedure:
"How do we start off with a Kilian Solera, what should we do when, how should we do it?" There was no help from Andalusia,
because the biological-aerobic maturation of sherry differs significantly from whisky maturation.
The winemakers use extremely old barrels to develop their fortified wines.
They are 500 liter butts that coopers bound from either American or Spanish oak.
Sometimes even made of chestnut wood.
We rejected the idea of filling all selected Solera barrels with the same New Make or whisky and came up with an alternative approach."
Long and intensive discussions and considerations within the Kilian team ultimately led to the creation and construction of a Kilian-specific Solera cask culture in which non-peated and peated Kilian distillates would continuously mature into whiskies in the near future.
The first rule determines the distillate:
"We decided always to choose the same malt recipe, refining, yeast and distillation method for the solera distillate,
so that a basic consistency of the whiskies will be observed.
Everything will remain identical,"
Mario Rudolf explains the approach.
NB: Kilian always sources the unpeated malt from German barley from the Weyermann Malters in Bamberg, while the peated malt with 80 ppm (HPLC measurement method) comes from the Scottish Maltings in Glenesk near Montrose, south of Aberdeen. Of course, the types of barley to be malted could change over the years as cultivation changes.
The second rule determined the barrel selection:
Mario Rudolf and Zoltan Fodi developed a three-stage barrel aging system consisting of a two-part Criadera 2 & 1 and a final solera 3. They were looking for the ideal aroma-defining casks for the non-peated and peated whiskies, because they wanted two separate peated and non-peated solera system.
According to their ideas, each cask should add specific aromas and contribute to the desired complex character of the two Solera single malts.
It sounded like a gamble.
But their previous experience in maturing Kilian distillates taught them to estimate the general aromatic effects of the different casks.
"We wanted our whiskies to have a Sherry flavour."
They therefore only discussed those cask cultures that had previously produced sherries from the D.O. Jerez-Xérès-Sherry. There was a choice of containers in which Fino, Manzanilla, Oloroso, Amontillado, Palo Cortado, Pedro Ximénez, Moscatel or sherry cuvées such as Cream previously matured. Their Kilian Solera selection was ultimately limited to those fresh barrels that had previously been filled with Fino, Manzanilla, Oloroso, Amontillado, Pedro Ximenez and Medium Sherry. They decided on a mixture of relatively old bodega butts from a former Bodega Criadera Solera as well as certified seasoned Sherry casks in which renowned bodegas aged their base wines for at least 18 months. The cask were set up by first-class Andalusian cooperages.
Rudolf's and Fodi's considerations and assessments ultimately came to the conclusion that a different selection of barrels should be used for their Sistema Solera for non-peated and peated distillates.
The selection they set up in 2020 formed the aroma-defining backbone of the St Kilian Solera and should not be changed during the future maturation phases. However, an exception may be possible:
"We also decided that a single cask could be replaced from time to time during the maturation phase if aromatic silence will be noticed.
But not all of the them,"
Mario Rudolf points out.
When did the St Kilian Solera begin?
Time had come in October 2020. The CTO Rudolf and his team started the development phase of the first St Kilian Solera for a peated malt whisky:
"The first filling of Criadera Two happened in October 2020."
Step 1
The stillmen distilled the base distillate twice in 6,000 liter Scottish Forsyth Swan Neck pot stills from an 80 ppm peated Scottish malt which came malt from Glenesk. Afterwards, Char 4 Virgin American Oak Barrels from the Independent Stave Company (ISC, 190 l) shaped the core distillate of the St Kilian Solera for a year. A few weeks before the initial filling of the Solera, the Peated Spirit celebrated its first anniversary of maturation on September 4th, 2020. (NB: Therefore, the Solera variant bottled in October 2023 is four years old).
Step 2
"We filled the top row the first year,
so the Criadera Two,
consisting of three five hundred liter Oloroso Butts with a one-year peated distillate."
Step 3
Afterwards, in the second year, the Kilian team filled the entire contents of the Seasoned Oloroso Butts into the second row, i.e. into Criadera One consisting of two Amontillado Bodega Butts (both were 20 years old, 500 liters each) and a thirty-year-old Fino Bodega Butt (500 liters). As with the Criadera Two, the origin of the casks is not communicated.
"These weren't seasoning casks, but real bodega casks from a Criadera solera,"
explains Mario Rudolf.
Step 4
After another third year, Criadera One was also drained and for the final solera maturation in six certified seasoned Pedro Ximénez barriques (225 l) from the Bodega Ximénez SpÃnola from Tablas in the D.O. Jerez decanted.
"We went through Criadera Two and One as well as Solera with our final product.
In the third year, our core distillate was finished three times, so to speak."
Step 5
When the Kilian distillers transferred the liquid from the Criadera 1 to the Solera, the three Oloroso Butts in the first row were of course refilled in the following October 2021. This time, however, it was a two-year-old peated spirit from the distillation periods of May and June 2019, which matured in first-fill Jack Daniel American Standard Barrels (190 l).
We chose this maturing peated spirit so that the fillings would be of the same age.
Step 6
In the third year, the Criadera 2 was topped up with a whisky matured for three years in a first-fill Jack Daniel barrel (the Peated New Make, as described above, came from the same distillation months May and June 2019).
"In the third year of 2022, however, we had a delay and were only able to refill in February 2023. So in spring all the casks of Criadera Two and One as well as the Solera were filled.
In October 2023, we were able to extract around thirty percent of the filling for our first release in 2023 from the Solera below, i.e. stage three.
It was only at this point that the actual solera began with the removal of thirty percent of the contents of Criadera Two, which filled from above down into Criadera One,
from which they had previously removed 30% and put it into the solera casks for further maturation...
from which we had also previously removed 30% of the contents for our inaugural St Kilian release.
At the same time, we refilled the Criadera Two with a three-year-old peated Kilian from a Jackie Barrel [thirty percent] "
According to our calculation, the Solera will reach an average biological age of ten years in 2032,"
Mario Rudolf emphasizes the current status of the Solera proceedings.
Step 7
With the annual Criadera 2 addition of a three-year-old St Kilian malt, which underwent basic maturation in Jack Daniel's first-fill bourbon barrels, the Solera will continue on an annual basis in the future.
"The Jackie thus brings about standardization and a balanced harmonization of the three-stage St Kilian-Criadera-Solera system."
The Criadera and Solera are always filled up to the bunghole during decanting and subsequent refilling. An ullage, a free head space in the cask, as it is common in Andalusia, is not allowed when refilling the Kilian Criadera and Solera casks, because the maturation conditions for sherry (flor formation, oxidation influx) are different.
The Angels' Share in the Kilian warehouses for Bourbon barrels is around 3 or 3.5% per year, for other casks there is loss of filling quantity between 1.5% and 3%. For comparison: The Angels' Share in Italian Amarone wine barriques reaches between 1.5 and 2% of the annual filling quantity.
Mario Rudolf's Solera Project. The beginnings in 2020 at the first distillery warehouses.
Whisky maker Rudolf says about the result, taking into account the legal requirements for brandy and sherry:
"When we always put a three-year spirit from Jackie barrels into the Criadera Two,
then after going through the three barrel stages we end up with the same calculation as with the brandies
at least one six-year-old St Kilian Solera Whisky.
but theoretically there is at least one drop that comes from October 2020...
according to the official calculation to the Spirits Regulations, the Solera will have an average age of ten years...
around October 2032 the Solera will be complete,
we have then reached the maximum average age."
Kilians Unpeated Solera. The Cask Types
For the mild, unpeated Kilian Solera variant, Mario Rudolf and Zoltan Fodi also chose a three-stage barrel maturation system consisting of a two-part Criadera 2 & 1 and a final Solera 3. But compared to the peated Solera, they changed to other types of casks.
The procedure for building up the Solera in June 2020 was similar to that of the peated Solera variant.
Step 1
In the first three years of building the St. Kilian-Criadera-Solera "...the whole set up started in June 2020 with the filling of the Criadera 2 with a distillate from December 12th, 2018..." which initially shaped Char 4 Virgin American Oak Barrels from the Independent Stave Company (ISC, 190 l) for just over a year.
Step 2
In June 2021, the casks in the top row were completely emptied after a year and their contents were filled into the Criadera 1 in the row below. The team filled the Criadera 2 with a two-year-old distillate from the same batch of December 2018, also matured in Virgin Oak barrels.
Step 3
In June 2022, the third year, the Criadera 1 was transferred to the solera casks.
The distillate flowed from the Criadera 1 stage into the solera barrels below, while the distillates from the Criadera 2 filled the barrels of the Criadera 1 again.
The Kilian distillers immediately filled the empty Criadera 2 barrels with the three-year-old virgin oak distillate from the same distillation batch from December 12, 2018.
"The non-smoky St. Kilian-Criadera-Solera system was finally born,
From 2023 onwards, we will fill the Criadera Two exclusively with mild Kilian malts that have matured for three years in first-fill Jackie barrels.
In the future, the removal and transfer from the Criadera 2 and 1 as well as from the Solera will be reduced to around thirty percent of the respective capacity of the casks."
Rudolf says,
"...We could have done the process differently, initially filling all stages of the Solera at the same time with the same distillate.
We had some thoughts, but what was crucial for us was how do we make the structure most efficiently from an aromatic and taste point of view?
There is no right or wrong, for us it felt right to choose an aroma-building and structuring method...
Up to now, the positive results confirm this approach.
We're off to a very good start with an incredibly charged product.
Now we can put an exclamation mark!
It will be exciting to see how the Solera changes over time."
Which barrel cultures are used for the mild St Kilian version?
For the unpeated Criadera 2, the Kilian team uses seasoned barrels made of American oak from the renowned Toneleria Tevasa in which a dry Manzanilla Sherry of the Bodega Baron of Sanlúcar de Barrameda flavoured the staves beforehand. From June 2020, 2 certified seasoned first-fill Manzanilla Hogsheads (250 liters) will form the twice-distilled barley spirit (see above) in the Criadera made from non-peated German barley malt (Pilsner Malt variety) from the malster Weyermann in Bamberg, Franconia.
In the following stage of Criadera 1 old seasoned medium sherry butts from the Bodega Ximénez-Spinola will be used. As with the peated Kilian version, the final Solera maturation takes place in certified seasoned Pedro Ximénez Barriques (225 l) from the Bodega Ximénez-SpÃnola from Tablas in the D.O. Jerez.
"In the third phase of maturation we only use certified seasoned Pedro Ximénez Sherry barriques from the Bodega Ximénez-SpÃnola.
These give our whisky an expressive and complex aroma profile."
With the annual addition of a three-year-old St Kilian malt, which undergoes basic maturation in scratched first-fill bourbon barrels from Jack Daniel, the solera will be continued in the future.
This allows standardization of the three-stage St Kilian-Criadera-Solera system.
The Criadera 2 is refilled every year after the 30% has been poured into Criadera One up to the bunghole with the one in "Jackie".
The St Kilian Solera System will be refilled only with matured single malt whisky in the future."
This means that a double-distilled St Kilian malt whisky that was originally matured for three years in first-fill bourbon barrels is actually finished three times in one way or another:
Finish 1 Subtle andelegant Manzanilla aromas,
Finish 2 with a mild, young medium-aged sherry and finally a
Finish 3 of an aroma-intensive sweet Pedro Ximénez sherry from organic vineyards. The Pedro Ximénez grapes grow on the slopes around the Ximénez-Spinola winery in Tablas, D.O. Jerez.
A selection of cask cultures. Virgin Oak Barrels from the U.S., Jack Daniel American Standard Barrels,
Manzanilla Casks, PX Sherry Casks and Sherry Casks at the St Kilian Distillery
Photos Copyright St. Kilian Distillers and The Gateway to Distilleries
Conclusion
It should add up. So we increase the aroma, the delicate aromas, the colour, the sweetness, the fruit...actually everything.
It's exciting to see what effect this will have and will look like from stage to stage...because no one has done anything like this in the single malt sector in Sherry casks before.. ."
the inventor of the St. Kilian Solera Mario Rudolf says.
However...
The Kilian Solera process is very complex: labour-intensive and above all expensive. In compliance with German Customs Regulations, the casks must always be completely emptied during refilling, the removal weighed, stored temporarily and processed for tax purposes. The meticulous documentation of the procedures is indeed very time-consuming. Each individual step is handwritten in the warehouse book and checked and countersigned by a Kilian employee who acts as a part time officer of the German Excise Authorities.
For further information please see St Kilian Distillery
About the Author
Ernie - Ernst J. Scheiner is the editor of The Gateway to Distilleries www.whisky-distilleries.net He documents over 150 distilleries photographically from the inside and describes the production of the whiskies in detail. Since studying at the University of Edinburgh he has been interested in the subject of whisky and has published in
Trade magazines like The Ireland Journal, the small distillery, Whisky Passion and The Highland Herald. Features and stories appeared in blogs like whiskyexperts, whiskefanblog and whiskyintelligence. As former head of the VHS Ingelheim, and now as a whisk(e)y tutor, he teaches distillation at colleges, organizes study tours and whisky culture tours to the sources of whisky.