Sherry Wine Part II
Maturation of Sherry
The Solera System
At the heart of the blending and maturing of Sherry wines is the Solera system that allows for constant production and a consistent style to be achieved by a Sherry producer. The Solera System and the Bodega it is housed in is at the core of the terroir of a Sherry. Sherry butts (massive 600L neutral oak barrels) are stacked in levels according to age with the youngest blend of wines in the top levels called criadera. The oldest level at the bottom is also a criadera, but is more commonly referenced as the Solera level. The oldest wine is in the Solera level and is where the wine will come from for bottling or move onto another new Solera System in the case of Amontillado which would have started out in a Fino Solera. The process starts with the removal of some wine from the Solera level for bottling or to another Solera and continue maturing. Since room at the bottom has now been made, wine from the last criadera level is added to the Solera level. This process is continued all the way up to the 1st criadera level, moving some wine down to each successive criadera. This makes room for wine from the sobretabla to be added to the 1st criadera to ensure all of the butts in that Solera system have effectively been filled and thus blended. The sobretabla is an inert vessel that holds the Sherry wine after it is fortified and before it enters a Solera. It’s an intermediary stop of only 6-12 months at most. There are two main paths to Sherry wine production once the still wine has been made and the first classification has been determined by Flor or lack of Flor development: biological or oxidative aging in a Solera.
Fino Sherry develops its unique taste from the accumulation of acetaldehyde created by the flor. The biological aspect of biological aging has everything to do with the flor, the interaction of yeast, nutrients, oxygen and alcohol which fuel the flor creation process. These components are all the natural aspects of the biological aging process that impact a Fino and Amontillado (initially) Sherry wine. The neutral oak butt is filled only 5/6ths of the way so there is room for the flor to continue to develop its cover cap which prevents the wine from oxidizing. The flor is a natural, furry looking yeast layer that sits on top of the wine in the barrel. The style of wines that have undergone biological aging are light in color, fresh and crisp, with a youthful character and high acidity. Typically a Fino is aged for 3 years in the Solera System and each criadera that is older has less flor. If a butt has lost its flor or it has partially died off then the wine in that butt is less protected from oxygen and can therefore show oxidative notes in the wine. Flavors and aromas of almonds, sea air and bread dough are most frequently perceived in a Fino Sherry. The wines are meant for immediate consumption as bottle aging will not benefit a Fino Sherry. If the wine is deep enough in flavor at this point it can be classified again as an Amontillado Sherry if so chosen to do so by the producer and will then be moved into a new Solera for further oxidative aging.
Oxidative aging is the second path of 2 that a Sherry can take in the maturation process. Sherry wines that are produced this way include Oloroso, Amontillado, and Palo Cortado. Unlike biological aging where oxygen is blocked by flor from oxidizing the Sherry wine while aging, no flor develops to protect the wine from oxygen and this greatly impacts the style of the wine to create an oxidative style of Sherry. The wines are initially put in wooden butts once initial fermentation is complete to see if a layer of flor will develop. If no layer of flor develops that is fine as this is the path that this specific wine will take and the oxygen is allowed to permeate the wine. Since these wines are also aged and blended in the Solera system, the fresher portions of wine that are passed down the criadera maintain a consistent fresh Sherry character in the wine. The style of wines that undergo oxidative aging are amber to tawny in color, with pronounced caramel, walnut and orange peel aromas and flavors with medium acidity. Alcohol levels are higher as the wines are fortified to higher levels of 18 to 23%. The higher alcohol initially comes from fermentation but it increases due to longer aging times were evaporation concentrates the alcohol content.