In the fourth part of our series on the art of blending, Westgarth Wines wine specialist Maurizio Broggi looks at the solera system and its role in Sherry making.

Hailing from Jerez de la Frontera in Andalusia, Spain, Sherry is one of the world's most esteemed fortified wines. Characterized by a wide and diverse range of styles, including Fino, Amontillado, Oloroso, Palo Cortado, Pale Cream, Medium, and Cream, Sherry production centers on a singular blending process known as the solera system. This fractional blending technique, originally implemented in the 19th century, serves to offset vintage variation and ensure the consistent preservation of the Sherry style.

Following fortification, wines designated for Sherry production undergo a temporary storage phase known as sobretabla, meaning ‘on the board’.

Traditionally, Sherry matures in old oak barrels, with the most prevalent size being the 600-liter "butt" made from American oak. Due to their extended age, these butts no longer impart significant oak characteristics to the maturing wines.

The solera system aims to achieve consistency and quality year after year by blending smaller proportions of younger with older wines. In the solera system, the barrels are divided into groups known as criaderas. Each barrel in the same criadera contains wine of the same age, thus each criadera contains wine of different age compared to other criaderas.

The oldest criadera is called the ‘solera’, a term that refers to the barrels positioned closest to the floor (or suelo in Spanish), which traditionally contains the oldest wine. The criadera with the next oldest wine is the 1st criadera, the 2nd criadera contains younger wine than the 1st criadera, the wine in the 3rd criadera is younger than in the 2nd criadera, and so forth. Each criadera’s barrels are grouped together in a specific area of the bodega.

To ensure the preservation of the solera system's unique character, regulations limit the annual amount of wine that can be drawn to a maximum of 40% of a solera's total volume. This practice guarantees that the majority of the aged wine remains within the system, contributing to the consistency and complexity of Sherry wine in the system. Additionally, legal requirements mandate a minimum age of two years for any Sherry drawn from the solera system for commercial bottling.

The solera system operates through fractional blending. A designated portion, not exceeding 40%, is extracted from each barrel within the oldest criadera (the solera) for potential bottling or incorporation into other solera systems. This volume is then replaced with an equal amount of wine drawn from the barrels in the 1st criadera, effectively blending a younger, fresher wine with the oldest component of the system.

This process continues sequentially through each criadera. Wine is drawn from a given criadera and used to replenish the barrels in the next, older criadera. Finally, the youngest criadera is topped up with the youngest wine from the sobretabla. This cascading method ensures the continuous introduction of younger wines into older wines, contributing to freshness, consistency, complexity, and superior quality.

It is important to note that reaching the solera level, the oldest criadera, is not a prerequisite for a wine's inclusion in commercial bottling. Sherry producers strategically draw wines from various criaderas, selecting specific age profiles to achieve their desired styles. For instance, wine for a Fino Sherry may be predominantly drawn from the 5th criadera blended with a smaller proportion of wine from the 4th or older criaderas to produce a fresher, entry-level style of Fino. More complex and higher quality wines such as Amontillado, Palo Cortado, or Oloroso will have a higher proportion of wines drawn from the solera’s barrels and the older criaderas for complexity and richness blended with a proportion of wines from younger criaderas to provide balance and freshness.

The selection and blending of wines from various criaderas and solera systems form the backbone of Sherry's complexity and stylistic diversity. Since many solera systems were established decades ago, each one invariably contains an amount of the original wine, ensuring a continuous thread of history within the final blend.

Want to read more? Take a look at some of our other blogs:

• • The art of blending: the fundamentals
  • The art of blending: red blends
  • The art of blending: white blends