Winecast: Sherry, Part II

Hello everybody and welcome to The Wine Cast. This cast is part two of what I'd hoped would be just a two-part series on sherry, but because sherry is both amazing and complicated, and because even I find 15-minute casts a little too much to take, it's going to end up being a three-part cast, at least. So what's on the docket for this cast? This cast is going to focus on the process for making sherry, specifically the process of preparing a wine for time in Solera, and how the Solera system itself operates. And in part three, we'll get a chance to do a survey of styles and then hopefully tie up any loose ends. And if we don't tie up all those loose ends next cast, well, there's always part four. There's a lot to cover, so let's get started. Depending on what your focus is, there are a couple of ways you could divide up the various styles in which sherry is made, but one that I think works well is to focus on the dryness or sweetness of the style. Dry sherries can be subdivided into those that are products of biological aging, like and those that are products of oxidative aging, the Olorosos, as well as two intermediate styles, Amontillado and Palo Cortado, that experience both of these styles of aging. Once you've got a good idea of the overall process that results in these dry styles, then it's a snap to make sense out of the sweetened styles of sherry that go by several names, but at their heart are just lightly sweetened versions of either biologically, oxidatively, or intermediately aged sherry. The process that results in naturally sweet sherrys is different enough from the process for dry and sweetened styles that it benefits from some additional unpacking, but it's still key to understand the main process to make sense of what's going on with these sherrys too. And finally, though not a separate style, recently some sherrys have been approved to receive age designations, and the specifics of that category deserve some attention too. Like I said, at the core of all these styles and designations is a process that begins after harvest and starts with pressing the grapes and fermenting the must. The grapes used in making a dry style will be exclusively Palomino, that, as we saw in the last cast, makes up about 98% of plantings in the region. Since Palomino is notoriously low in acid for a grape, it's standard practice in Jerez to acidify the Palomino must before fermentation, formerly with gypsum and more recently by adding tartaric acid. These days, fermentation of the base wine takes place in a large stainless steel tank, and though there will be a cooler, later stage, the initial fermentation runs pretty hot and burns off some of the varietal aromas from the Palomino, with the result being a very neutral base wine, with an alcohol by volume somewhere between 11 and 12.5%. After fermentation, and even prior to the base wine's first classification, flor will begin to grow on the surface of the wine. The flor is a velo, or veil of yeast, composed of up to four different varieties of Saccharomyces cerevisiae, the same species of yeast that ferment grape juice into wine. And these varieties are similar, but not identical, to the yeast strains that form veils on the Van Jon of the Jura, or the dry Samorodnes of the Tokay region. Like other yeasts, these strains are more vigorous, more active, and form a thicker veil in more humid regions, like on the coast of Jerez, around Sanlúcar de Barrameda. This veil protects the wine from oxidation, both by shielding the wine from the oxygen in the space between the surface of the wine and the barrel, or the ullage, and by consuming most of the oxygen in the barrel. In addition to oxygen, the flor consumes sugar, alcohol, acetic acid, and glycerin, but produces acetaldehyde, a compound that contributes to the unique sensory profile of wines aged under a veil of flor, a profile that includes notes of citrus oil, apple peel, iodine, seafoam, and unsurprisingly, a yeasty quality. Flor isn't immortal though, and over time, individual cells die and their remains fall to the bottom of the barrel. They're in to form a blanket called the cabezuela, and the dead yeast cells continue to contribute to the profile of the wine, particularly the yeasty, bready aspects of the profile, through autolysis or decomposition. Eventually though, the entire colony will die, and most colonies of flor don't survive beyond about seven years. After fermentation, the new wine receives an initial classification that tries to rate the overall quality of the wine, as well as get a sense for whether the character of the wine is one of finesse or of greater richness, a characteristic that the Spanish call gordura, literally fatness. Wines with finesse will be designated for biological aging, or aging under flor. They'll be fortified to an alcohol by volume of 15 to 15.5%, a range that's considered optimal for flor growth, as the flor will need to consume alcohol as a source of nourishment. The fortification is accomplished with a neutral spirit that's distilled to a concentration of about 96% alcohol, meaning that not very much is required and only about 3.5% of the total volume of a sherry is usually distilled spirit. Once a wine is fortified, it's called a sobretabla, a wine set aside for observation before it's incorporated into a solera. What's being observed? In the case of wine slated for biological aging, primarily the flor, to make sure that it's developing in a healthy and consistent way. This observation can take, depending on the practice of the house making the sherry, anywhere from a few months to usually around a year, but some houses will even go as long as two years. What about wines with less finesse and more gordura, or richness? These wines are designated for oxidative aging, and they receive a stiffer dose of the distilled spirit when they're fortified, raising their alcohol level to around 17%, a level that becomes toxic to flor yeast and causes the nascent colony of flor to die. The sobretabla stage for these wines isn't as crucial as for biologically aged wines because there's no flor to observe, and just a few months usually does the trick before these wines are incorporated into a solera. So what is a solera? It's a complex system of tiers of barrels for the purpose of fractional or partial blending of wines from different vintages. Confusingly, both the entire system of tiers and the lowest tier, or the tier containing the oldest wine, are called the solera and the word itself derives from the Spanish word suelo, meaning floor. Though pictures of soleras like this one often show the barrels stacked on top of each other and that's how the system was first set up, the barrels don't have to be stacked as long as it's clear which tier contains the oldest wine, which contains the second oldest wine, and so on. In fact, it's the practice of some sherry houses to keep different tiers of their soleras in different buildings or parts of the same building, either because they think a different location will provide a better microclimate for what's going on in a particular tier, or because their soleras have so many tiers, some can have as many as 15 or more, that it would be impractical to say nothing of dangerous to try to stack them. Speaking of the origins of the system, it probably got going during the 1790s in the coastal city of Sanlúcar de Barraneda, a city well situated for the development of flora in barrels, and the system was first used exclusively for biological aging and only later, around the late 1800s, applied to wines that were aging oxidatively. Before the advent of this system, most wines from Jerez were single vintage wines. How does it work? Well, the barrels were arranged into tiers that may or may not be stacked, or even nearby, with the tier containing the oldest wine, called the solera, and deriving its name from its position closest to the floor, if the barrels are stacked. Layers containing younger wine or more recent addition to the system are called criaderas, or nurseries in Spanish. The tier with the next oldest wine from the solera is called the first or primera criadera, while the tier with the next oldest wine from that is called the second or segunda criadera, and so on, depending on how many tiers or criaderas there are in the system. Soleras operate using a scheme called fractional blending. Assuming you have a functioning solera in place, you start fractional blending by removing a portion of the wine in each of the barrels, in each criadera on down to the solera tier, and then blending the wine from each tier together in a vat, tank, or other vessel. About one-third of the contents of each barrel are what's permitted to be removed each time this process is done, but many quality-minded producers often remove less than that amount, usually closer to 5-15% of the volume of wine in the barrel. The wine that's removed from the lower tier, the solera tier, is then bottled and sold, and if this were all that there were to the process, the solera would run dry pretty quickly. But each of the tiers of the solera are refreshed after each removal with the blended wine from the tier above it, while the topmost tier, or last criadera, is refreshed with wine from the sobre tabla, that reserve of wines from the current vintage that is now ready for integration into the whole system. The process of removing wines from one tier for blending is called the saca, or removal, and the process of refreshing each criadera with wine from the saca is called the rocio. That in addition to being the Spanish word for dew, as in that thing that you find on your lawn on cold mornings, means something like sprinkling here, which is how the wine is introduced into the barrels, with a very gentle sprinkle, especially in soleras where biological aging is going on so as not to disturb or damage the layer of flora. This is a pretty remarkable system for blending wines, theoretically from a limitless number of vintages, and some of the soleras in Jerez are very old, with examples dating back to the 1830s when the system was still new. The average age of the wine in the solera as a whole, and in the bottom tier that's withdrawn for bottling can be determined by calculation, if the production house keeps careful records of how often they withdraw and refresh the wine in their soleras, and most houses usually do. Why go through this process? Well, it's likely that it was developed in the first place as a means to systematically and consistently refresh the flora in barrels that were undergoing biological aging, thus allowing the wine to spend more time under flora and get the full benefits of that sort of aging. Also, by blending and reintegrating the blended wine into the system, the solera method allows for the creation of a consistent house style for the wine to be released, regardless of whether the wine was biologically or oxidatively aged. But most importantly, and probably most unexpectedly from the point of view of the originators of this system, each solera tends to take on a life of its own, become a living system all its own, with an individual character that both affects and is affected by the wine introduced into it, making the whole process a sort of end unto itself. Thanks for joining me for another wine cast. Don't fret, there's more to come with the next cast set to cover the different styles of Sherry mentioned at the beginning of this cast in detail, as well as to hit a couple of other topics. I've got the slides for that cast already, so look for it to be coming up fairly quickly. I hope the ending of this cast wasn't too abrupt, but I really do want to be considerate of my listeners' time and provide you with casts that are a reasonable length to get the most out of. If you did get something out of this cast or otherwise found it helpful and interesting, please like and subscribe if you haven't already, and, especially since there is a lot to cover when it comes to Sherry, let me know if you have any particular questions or issues that you want addressed in the next cast. I'm your host, the Unknown Winecaster, and I'm out. Enjoy the grape, but always enjoy it responsibly.