Inside the solera

Step inside any historic bodega in Andalucía’s ‘sherry triangle’ and you’ll find rows and rows of ageing casks – at first sight, not much different from a typical dunnage set up in a Scotch whisky distillery warehouse. But there’s a key difference – and that’s the reliance of the bodegas on their solera systems.

The process is fundamental to producing high-quality and consistent sherry, and its brilliance lies in a meticulous design and straightforward operation to manage a never-ending form of ‘fractional blending’ between old and new casks.

Within a solera system, the casks are organised in tiers or rows. The bottom row is known as the solera – meaning ‘on the floor’ in Spanish – and contains the oldest liquid. Above this, progressively younger liquids are stored in the criadera (meaning ‘nursery’) levels, which are designated by age.

Periodically, a portion of up to a third of the liquid is drawn from the solera on the bottom row for bottling, in a process known as ‘saca’. This volume is then replaced with liquid from the criadera above it, which is in turn replenished by the level above. Finally, new wine is added to the top criadera to fill those casks again.

As the liquid moves down through the levels over time, it blends with the older liquid, creating a consistent and balanced flavour profile. This continuous mixing, or fractional blending, ensures the final product maintains a high quality and complex character, with the older wine’s characteristics always influencing the younger additions.

As Antonio Flores, master blender at González Byass, explained it to me on a previous visit to Jerez: “This is a key part of the sherry story. Unlike the rest of the wine world, which uses the vintage system to preserve the singularity of each year’s bottlings, the solera system preserves the homogeneity of the style.”

Within a solera system, the casks are organised in tiers or rows. The bottom row is known as the solera – meaning ‘on the floor’ in Spanish – and contains the oldest liquid. Above this, progressively younger liquids are stored in the criadera (meaning ‘nursery’) levels, which are designated by age.

Periodically, a portion of up to a third of the liquid is drawn from the solera on the bottom row for bottling, in a process known as ‘saca’. This volume is then replaced with liquid from the criadera above it, which is in turn replenished by the level above. Finally, new wine is added to the top criadera to fill those casks again.

As the liquid moves down through the levels over time, it blends with the older liquid, creating a consistent and balanced flavour profile. This continuous mixing, or fractional blending, ensures the final product maintains a high quality and complex character, with the older wine’s characteristics always influencing the younger additions.

As Antonio Flores, master blender at González Byass, explained it to me on a previous visit to Jerez: “This is a key part of the sherry story. Unlike the rest of the wine world, which uses the vintage system to preserve the singularity of each year’s bottlings, the solera system preserves the homogeneity of the style.”

The diversity and historical depth of the solera system become apparent when visiting bodegas such as Ximénez-Spínola. Here, owner José Antonio Zarzana draws samples from the bodega’s solera systems that date back to 1918 and 1964. These soleras have been in continual use during these periods, although the casks have been replaced over time, reflecting a rich legacy of flavours that have been meticulously preserved.

“The solera is typical of a sherry bodega and supplies casks that have been used for years – possibly even decades – aging sherry,” explains José Antonio.

These are the ex-bodega casks that have been purchased by The Scotch Malt Whisky Society, and which have already produced several outstanding whiskies for our members. They’ve certainly hit the spot from SMWS head of whisky creation Euan Campbell’s point of view.

“The casks that we source from Ximénez-Spínola are very high quality,” says Euan. “An enduring memory for me was being able to taste the wine directly from our casks at the bodega, just weeks before the wine was bottled, and the casks shipped to Scotland. They offer a more subtle impact than sherry-seasoned casks, and match particularly well with unpeated, fruity distillate styles of whisky.”

Inspired by their close relationship with several bodegas in Jerez, our Whisky Team have now taken this to the next level and have opted to create the Society’s own solera maturation system in our maturation warehouse.

Cask operation planner Ed Furmston-Evans explains: “Solera systems are a traditional way of maturing sherry in Jerez, where the casks at the bottom hold the oldest stock and as they deplete stock from the casks above gets moved down. So, you end up with this ever-developing blend which allows for really great consistency and massive complexity.

“Because of the way the solera systems work, what we’ll get coming out of it is a constantly evolving product that will always be slightly different. And like the rest of our offerings, it will always be about exploring new flavours and really giving variety into our mix.”

The Society’s Whisky Team are of course no strangers to innovation, and perhaps one of the most exciting aspects of this 20-cask solera system is they’re not 100 per cent sure what will come next, or when.

“For us, creating a small-scale solera system is a fun way to play around and experiment with getting new flavours inspired by our heroes in the sherry region,” says Ed. “As for what we’re going to get from it, or when we’ll be bottling anything from it, members will have to wait and see.”

The Society’s first release from the SMWS solera, Cocoa drift, is now available