The Jerez region has a strong poetic tradition which has found its way into the local vocation – winemaking. From albariza (sunrise-curls) to rocio (morning dew) as discussed in earlier articles, Jerez wine vocabulary is full of charm and romanticism. It is unsurprising, therefore, to find our next topic deals with a phenomenon none as flor – the flower - or more descriptively el velo de flor – the veil of flowers.

Flor is a single-celled fungi which can be found in some bodegas in the Jerez region. Forming spontaneously on the wine’s surface, flor and liquid metabolically interact to produce a number of clearly recognisable characteristics. Powdery-white in appearance with a sponge-like texture, there are several varieties which thrive under different conditions. Flor imparts inimitable characteristics on Fino, Manzanilla (and Amontillado for a time) and is a living substance which explains why these styles are called biological wines.

In order for flor to flourish, like any living organism, it requires certain conditions. Most of these are fairly obvious; oxygen and climate being of particular importance. To allow respiration, the botas are filled to around 5/6s leaving a pocket of air at the top of the bota. Despite the warm summers, the temperature and humidity need to be cool and constant. Ideally the temperature is around 18-22 degrees centigrade with 70% humidity. These conditions are created with architectural engineering (high ceilings, orientation, ventilation etc.) and by sprinkling water onto the bodega’s sandy floors. In much the same way as a rose garden, the flor will blossom to a greater or lesser extent depending on these key parameters. The other thing to bear in mind is that flor can not survive with an ABV greater than 15.4%. Above this percentage and the flor starts to die away which is why Oloroso et al are all 16% or above.

Within the flor family there are several key varieties. The most prevalent, by far, is Saccharmoyces Betticus which commonly constitutes around 3/4s of the active flor. Betticus is the fastest flor to form following fermentation and is fairly prolific. Other Saccharomyces include S. cheresiensis, S. montuliensis and S. rouxi. Montuliensis can often be found in botas where the flor has developed for many years. Every bodega will have their own atmosphere which provide conditions for a unique mix. The difference is noted in the final glass with subtle sensory nuances which are clearly discernible from bodega to bodega, and even bota to bota. [Recent research suggest that each bota’s Saccharmoyces make-up depends on the type of albariza soil where the grapes came from; this is extremely interesting and a topic I will cover in a subsequent article.]

A healthy, rigorous flor transforms a fairly neutral base wine into a unique style. This is achieved in several ways. Firstly, for its own survival the flor consumes glycerine resulting in a bone-dry wine. Fino and Manzanilla contain a decimal gram of residual sugar per litre, practically nothing. At the same time, the best examples of this style are not austere or sharp, but have a rounded feel in the mouth with a generous texture. This is thanks to yeast cells which die and fall to the bottom of the bota and gradually dissolve back into the liquid (known as cabezuelas – flower’s heads). Vitamins, amino acids, proteins and enzymes provide concentration and complex aromatics. Indeed, these added perks are part of the reason Fino and Manzanilla are seen as healthy options not just for the soul but the body too (I’ve never had a hangover from either).

Surprisingly given that most Finos and Manzanillas are at least over 4 years old, the wine retains a fresh, lemon colour; again this is thanks to the veil of flor. Without the blanket of yeast the liquid would be in contact with the air. Furthermore, despite the 1/6 of space within the bota the flor consumes the spare oxygen keeping the wine free from oxidisation.

A final consequence of flor’s metabolic intercourse and perhaps its most recognisable peculiarity is the pronounced nature of the final liquid. The yeast within the flor contains high levels of acetaldehydes (AcH) which have a pungent characteristic and unique flavour profile (bread dough, nuts). The boiling point for AcH is extremely low at 21 degrees centigrade which means the aromas are volatile and pronounced.

Despite all these facts and the cognizance around flor, like all great discoveries there is a sense of mystery too. In the same way that a cuvées’ terroir cannot be explained perfectly through science, the character of a biological wine is very much dependant on the flor and the metabolic reactions that take place over many years. Like a flower, the performance of the blossom varies from season to season and the same is true of our viticultural flower. The name is not only figurative but also alludes to the wonderful aromas, texture and substance the flor imparts on the final wine. Afterall, wasn’t it a great Sherry fan who wrote "What's in a name? That which we call a rose. By any other name would smell as sweet."