P.X. SHERRY CASK FINISHED BOURBON:
HISTORY & DISTILLING PROCESS

Pedro Ximénez (sometimes Pedro Ximinez, Ximénès, Jimenez, PX, or P.X.) is a description for naturally highly-sweet dessert wines. These wines are actually created with a  grape variety with the same name... 

What is PX Sherry?

Pedro Ximénez (sometimes Pedro Ximinez, Ximénès, Jimenez, PX, or P.X.) is a description for naturally highly-sweet dessert wines. These wines are actually created with a  grape variety with the same name. That’s right, “Pedro Ximénez” is actually the name of a specific genetic variety of grape, not a person or winemaking family - as many assume. In order to legally use the name “Pedro Ximénez” or “PX Sherry” the wine has to contain at least 85% of Pedro Ximénez grapes. It is a lot like the legal definition of bourbon; where to be a true “bourbon” it must have a mash bill of at least 51% corn, a barrel proof of no higher than 125 proof (although lower barrel proofs typically create more complex flavors), aged in new charred oak barrels and made in the USA. 

For Pedro Ximénez, the grapes are either picked in a condition that typical wineries would consider “over-ripe” and/or dried in the sun to concentrate the sugars for a richer and sweeter raw material. The grapes, commonly referred to in the industry as “P.X.,” are intensely sweet, especially when the P.X. grapes are dried in the sun in a process called asoleo. 

The PX (Pedro Ximénez) winemaking process

Soleo (from the root “Sol” meaning “sun”) or as more commonly called “Asoleo” is a process of sun-drying grapes before pressing them. In all actuality, it is very similar to the dried raisin or other sun-dried fruit making processes. This process is primarily utilized for Moscatel grapes and Pedro Ximénez, or P.X. grapes.
The soleo process usually lasts one to three weeks, but it depends on the weather conditions, the grape harvest in a particular year, the type of wine being made and the desired end wine finish desired. The soleo or Asoleo process is a labour-intensive work of love and history: the grapes are carefully spread out by hand and turned over once a day, while removing any bad grapes, keeping pests at bay and ensuring a consistent overall drying process.

After the grapes are finished curing/drying in the dry open air environment on esparto (straw) mats, or more traditionally round straw mats called redores, they are ready for processing. The majority of PX Sherry grapes originate from the Montilla-Moriles area which is a DO wine zone in Andalucia, southern Spain. The Montilla-Moriles region, centered around the towns of Montilla and Moriles, is located about 45km (25 miles) south of Cordoba and 100km (60 miles) north of the Mediterranean coast at Malaga. It is the most northerly of Andalucia's DO wine regions., where the dry mountain climate lowers the risk of curing problems which might potentially destroy the dried crop.

Pressing Pedro Ximénez (P.X. Sherry) Grapes

Pressing the PX Sherry grapes or “pasas” as they are commonly called -  is much more difficult than the process for fresh grapes, since there is less juice. Processing Pedro Ximénez grapes is typically done using vertical presses with the straw mats in between layers of dried grapes. Unlike the case with traditional grapes, the PX Sherry grapes have a very high sugar concentration; this is what prevents spontaneous fermentation. Once the fermentation process starts, the P.X. Sherry wine will naturally stabilize at 10 percent alcohol (10% ABV / 20 proof) and left to rest for several months before the fortification process.

P.X. Sherry History

Historians aren’t sure exactly when the soleo/asoleo process began Many agree that the process of using P.X. Sherry grapes and the process of making PX Sherry wine dates to ancient Roman or Greek times, however, some archeologists claim it was introduced by the ancient  Moors. Despite it’s origins, it is definitive that all PX Sherry producers have abided by the intensive process and standardized craft since the early 1800s. 

During the asoleo process, Pedro Ximénez grapes loose about 10-15% of their water/juice weight. The soleo process actually reduces the total (absolute) amount of sugar in the Pedro Ximénez grapes but the finished wine is much sweeter than most all other wined. How is this possible? With less water left in the Pedro Ximénez grapes after the drying process, the ratio of sugar-to-water is increased (from 300 grames per litre of mush to around 450-480 grams per litre). So, less dilution of sugar vs juice/water for total volume of raw grapes. During the process, Pedro Ximénez asoleo changes the viscosity of the resulting juice while also reducing the amount of naturally occurring malic acid and tannins. These chemical changes lead to different aromas and flavour characteristics of the finished PX Sherry wines.

Pedro Ximénez / P.X. Sherry grape juices are then added to oak “solera” casks where they mature/age for various periods of time. The casks themselves may be decades or even centuries old. When P.X. Sherry wines are bottled, they is taken from the group of oldest casks (which are never fully emptied). These are then topped up with wine from the next oldest age group casks, and so on down the line. 

Sometime around the mid-to-late 16th century, whiskey makers began storing their spirits in sherry casks used for transport from Spain, since the winemaker’s production-use casks were used until the integrity of the wood would no longer be feasible for aging wine. These casks usually only held P.X. sherry for a few weeks or months, and were emptied upon arrival in the United Kingdom. Since PX Sherry was a very popular drink in the UK, there were ample casks going unused. Whisky (Scotch) makers seized the opportunity for free aging casks.

This was the dawn/origin of the finishing process for whiskey in PX Sherry casks. Although at that time, scotch whisky makers were very proud of their traditional spirit flavor, so storing the whisky in vessels that only held PX sherry for a short period of time was ideal. The flavor profile didn’t change much. Fast forward to modern times, and the opposite is true. Now American whiskey makers and bourbon makers alike are experimenting with these P.X Sherry casks to create bold and complex new finishes for consumers who appreciate the depth of notes created by true PX Sherry cask bourbon and whiskey finishing. 

Pedro Ximénez or “P.X. Sherry finished bourbon

While the process for storing whiskey in used P.X. Sherry casks may not be new, the process of aging true Kentucky Straight Bourbon Whiskey in P.X. Sherry casks is definitely a process perfected by a very scarce sample fo the whiskey and bourbon making industry. 

The most complex example, involving attention to every detail would include aging raw, high-grade distillate in #4 charred new oak barrels before being transferred to former PX sherry casks for an additional six months of maturation. But wait! Isn’t part of the allure of true “Kentucky Straight Bourbon Whiskey” is that it is free from any additives - even passive ones it may have collected via the aging process of extracting new notes and flavors picked up by the impregnation of residual P.X. Sherry left in casks? 

Surprisingly, that answer is “no.” You see, once the legal requirements for the bourbon making process are fulfilled, distillers can add flavors (no recommended), or experiment with various finishing processes to create truly exceptional, one-of-a-kind bourbons. So, in essence, and legally speaking - these are true “bourbons” however, they are engineered to offer so much more depth and flavor than traditional “straight” bourbon whiskeys. That little bit of sherry left in the wood gives the bourbon whisky delicious new flavors like toasted nuts, dried fruit, bittersweet chocolate, and warm spices.

This is the underlying mystery, the profound beauty of America’s native spirit. From field to grain, distiller to process, mash bill to aging process - bourbon is a form of artistic expression. In a world where so many choices are illusory; and products maintain more similarities than unique differences - it is refreshing that some distillers are not turning off the creative mind once the bourbon has merely satisfied a legal requirement. No, the brave new pioneers fo the bourbon industry are pushing the envelope; creating truly memorable and impossibly complex finishes like bourbon finished in rare P.X Sherry casks. 

Bourbon Brands finished in P.X Sherry (Pedro Ximénez) casks

Of the brands available which offer P.X. Sherry cask finished bourbons, only Dareringer - a Kentucky Straight Bourbon Whiskey made by Rabbit Hole Distillery - fits the bill when it comes to originality and complexity.

 Of the brands available which offer P.X. Sherry cask finished bourbons, only Dareringer - a Kentucky Straight Bourbon Whiskey made by Rabbit Hole Distillery - fits the bill when it comes to originality and complexity. They start with toasted barrels, fired over a wood-fired flame before charring, a process that takes up to 20 minutes per barrel. Toasting the barrels before charring them coaxes sugars from deep in the fibers of the wood which mingle with the distillate during the aging process, giving Dareringer an unparalleled complexity and flavor.

Dareringer enters the barrel at a low entry proof, and the finished bottled product is “small-batch” meaning no more than 15 barrels are selected at a time for bottling. Perhaps one of the most defining characteristics of this truly unique bourbon is that it is never chill-filtered. Many bourbon distillers chill-filter to improve the shelf-appeal of their bourbon - removing any so-called impurities that may make the bourbon less than crystal clear. The truth is, these are not impurities at all, rather naturally occurring oils and congeners that separate standard, mass-produced whiskeys and bourbons from more refined and exquisite bourbons like Dareringer. 

After a thorough aging process, the Dareringer bourbon would be exceptional as it is. However, it isn’t quite finished yet. The bourbon is then transferred to PX Sherry Casknolia casks from Spain winemakers to age further - a full six months further. During this extra step, the bourbon pulls the P.X. Sherry from deep within the wood, and together they dance and mingle to become something inexplicable.

Something that is still very much the defining essence and characteristic of bourbon - and every bit as such in the legal definition - however, this new elixir is compounded with an unimaginable spectrum of flavors. 

One sip and you are immediately transported on a journey stretching from the far reaches of Spanish vineyards and hundreds of years of family tradition in PX Sherry winemaking - to the history of bourbon; the romance and deeply curated love of one of the oldest and most protected spirits in the Americas. It is so much more than a sip of bourbon - it is a sip of warm Spanish sun and the breezy oceanic air that dried the sweet, sticky and rich fruit grown in the same soil for hundreds of years.

It is a sip of a mighty American white oak that grew for over two centuries - witnessing the abolishment of slavery, civil rights movements, the civil war, natural disasters, peace treaties, the rise (and fall) of sovereign nations - and a wealth of history. Some might say you can actually taste the collective history of the entire world in each and every glass. 

So, the next time you desire something truly unique, something truly extraordinary - think about trying a fine bourbon whiskey finished in P.X Sherry casks. If you really want something special, try Dareringer P.X. Finished bourbon finished in Pedro Ximénez casks by Rabbit Hole Distillery. The process has yet to be replicated. It appears it may never be. Unique to it’s core.