is a wine word that you may have heard mentioned in conversations about Fino or
Manzanilla Sherry. Do you know what it is? And what it does to a wine?
Flor – A Collection of Yeasts
is actually a collection of yeasts – and good’ yeasts at that! While
flor yeasts can carry out the regular ‘fermentation’ activities (i.e.
converting sugars into alcohol) of other wine yeasts, they are best known for
their role in the development of Fino style Sherry.
the Sherry region, the flor yeasts collectively form a veil or film on the
surface of certain young Sherry wines. These wines are stored in wooden casks
known as butts (i.e. 600 liter American Oak barrels), which are not filled to
the top, leaving enough room and air for the flor to develop.
will not survive on wines above 16% alcohol.
does not form on all Sherry wines. Sherry is a fortified wine. Wines destined
for Fino style are only fortified to 15.5% whereas those destined for Oloroso
style are fortified to 16%. Above 15.5% flor yeasts cannot survive. An
environment 15% to 15.5% alcohol is considered ideal for flor to
Biological Aging – Maturation under a Veil of Flor
that is matured under a film or veil of flor undergoes what is called is called
biological aging. Flor provides a protective layer on the wine, preventing
any oxygen from influencing the style. This is the opposite
to Oloroso style Sherries, which have no flor protection and age
The Magic of Flor
well as preventing oxidation, flor yeasts do all sorts of other things that
result in creating the characteristic Fino or Manzanilla style. The flor
yeasts interact with the wine. They metabolize or consume the glycerol and nutrients
in the wine, as well as some of the alcohol. As they do this they also
significantly increase the amount of acetaldehyde, which gives Fino Sherry its characteristic
sharp aroma and taste.
result of all this is a pale colored, extremely dry wine, with a noticeable
acetaldehyde, green olive, nutty aroma and flavor.
How Flor Survives – The Solera System
all the nutrients and glycerol have been consumed the flor yeasts die off.
However, thanks to the traditional Solera maturation system of
fractional blending, there is a regular addition of a newer/younger wine into
each cask. The younger wine brings nutrients to enable the flor yeasts to
continue to grow.
blending is a dynamic maturation system, by which wines
from different stages of the maturation process are blended together.
Some liken it to keeping the young wines in touch with their ancestors!
Flor – Not just a Sherry Phenomenon
is the most celebrated flor influenced wine, there are a number of other wines
around the world that are also flor influenced. The most important of these are
the Vin Jaune wines from the Jura area of France, and
certain styles of Tokaji from Hungary.
(Image: Underlying image by Sadovnikova Olga/Shutterstock)