Inside the Solera

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.

How it works

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.”

A legacy of flavours

José Antonio Zarzana

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.”

Solera-inspired touch

It’s not only ex-bodega casks that have been used in sherry’s solera systems that are in demand. The whole concept has been adopted by some distilleries, notably Glenfiddich’s Solera 15 and Speyburn’s Solera 25, while in Australia Starwardand Sweden’s High Coast are also producing bottlings using their own versions of the solera system.

Now the Whisky Team are taking inspiration from their time spent in the bodegas of Jerez to set up the Society’s own solera system. It’s early days, but members can look forward to the release of SMWS solera bottlings in the future – watch this space…