Continuing the context....this time let's talk about Sherry

Hey there,

Our last context discussion was on sugar in wine, if you missed it you can find it here.  This time around I wanted to discuss Sherry and clarify what type of wine this can be, as it's often misunderstood, and why it is actually that way from a process standpoint. There are two major camps of process that will dictate the finished style - biologically aged and oxidatively aged. Both of these approaches will include the fractional blending system of solera but they differ in the inclusion or exclusion of flor.

Let's start with the easy one, oxidative aging, which is fairly self explanatory in the title. The wine is introduced to barrels in the criadera of the solera and is aged there until the scales are run and it's fractionally been blended with another criadera and so on until it is bottled. This process usually takes years and during this time the wine is exposed to oxygen just like any other still wine is during barrel aging, but at a more subjected degree due to the extended time in barrel. So what you end up with are very oxidative characteristics in the wines - toffee, roasted nuts, dry caramel, dried/dessicated fruits, torrefaction etc. They are very aromatic and rich, which is where the name oloroso is derived from, meaning odorous in Spanish. These wines are defined as being chemically oxidized, meaning that the entire wine in all it's components have been exposed to oxygen and transformed due to that exposure. Phenols, anthocyanins, alcohol and other components in the wine are together altered to create what we perceive in the the glass and is the magic of the style.

Biologically aged wines on the other hand will be aged in criaderas with the inclusion of flor living in tandem with the wine. Flor is a type of yeast and is an amazing collection of little organisms that grow on top of the wine and feed off a number of things in the wine including alcohol (both ethanol and glycerol), sugars and most importantly for this initial discussion - oxygen. The film of flor on top of the wine will protect it from oxygen from above and will consume any oxygen dissolved in the wine from ingress through oak and or racking from below. This makes all biologically aged wines reductive wines. The definition of reductive is the absence of oxygen, but I often hear fino or manzanilla being described as oxidative which is not the case. Now, there are characteristics that invoke flavors reminiscent of oxidation like almonds, saline and such, therefore it is easily confused. These are a result of a process of flor that will biologically oxidize one particular component of the wine which we'll dive into on the next post. All the other components are not oxidized.

See you in the next post for the nerdy details!