Tips on Bottle Aging
Written By: SUSANNE LOMATCH
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Color evolution in bottled wines is influenced most by polymerization of flavonoids in
reds, and the oxidation of phenols in whites. Reds evolve from bright to brick, and whites
evolve all the way from straw or golden to deep yellow or even a yellow-brown.
Putting all of these aspects together, how can we predict which wines will age well? My
primary criterion is that the wine ages to a balance that simply didn’t exist before it was
cellared. As noted above, the presence of both acids and tannins are important to the
aging process, as are pleasant, vibrant aromas. Research suggests that in red and rosé
wines, balance tends to correlate with very high tannin to anthocyanin ratios. The
polymerization process between these two is crucial in the aging of red wine, bringing
balance and stability of color. In white wine, balance and color derive more from the non-
flavonoid and acidic (high tartaric acid and low pH) content, and the oxidation process.
So generally, if a wine is missing tannic structure it likely is not a good candidate for
aging, especially in reds. Likewise, if there is a lack of acidic structure, it is also not a
good candidate, especially in whites. And indeed, my experimentation has borne this out.
Reds that I’ve aged that didn’t have much tannic content but had good acidic structure
tended not to change very much in terms of taste/mouthfeel, even over long periods of
time. Sediment was nonexistent. On the flipside, reds that were rich in tannic and acidic
structure, but that were too astringent to drink very often evolved to something more
gracefully balanced, with significant sediment. Whites that aged well tended to have their
acids ‘mellow out’ over time, developing a smooth, creamy texture. Barrel-aged whites
fared best.
Many readers have probably seen the general aging guidelines for various wine varietals
and blends, and I reproduce them below in terms of upper ranges. My experience has
been that these are not too far off, especially for Pinots – unless you start with a Pinot that
has a significant amount of tannin, anything beyond the 5-year period is likely not going
to yield a better wine. Note the lesser aging period for Merlot – this is due to the natural
tannic content being lower in Merlots, versus Cabs or Syrahs, and is one reason why
Merlot is used in many blends, such as Bordeaux and Meritage. Some winemakers
aiming for balance and aged character in a just-released vintage use a variety of
techniques prior to bottling: micro-oxygenation (oxygen infusion) to accelerate tannin
polymerization; and/or fining, which involves adding agents like albumin, casein and
gelatin that can bind to tannin molecules and precipitate them out as sediments. But as
elucidated earlier, finding such balanced specimens at an early age is not as common as
you’d think – hence the motivation for bottle aging.
My scientific background urges me to go further than the generalizations I’ve discussed
above, as I did use the rigorous term ‘predict.’ To get more specific one needs to know
the technical details of how the wine was made before bottling, and how long it has been
since bottling. More wineries and winemakers are releasing this technical information,
and the details can only benefit those looking for predictive capability. So what type of
information is relevant? Acid concentration and pH are important, as low pH wines have
a greater capability of aging. Lot yield, percent (%) de-stemmed, time periods for the
soak-fermentation-maceration cycle, barrel composition, time periods for sur lie and
sulphurization cycles, and details on fining, additives and filtering are all pertinent to
some extent. Low lot yields tend to produce wines with less water and a higher ratio of
sugar, acids and phenols, giving the wine aging potential. De-stemming reduces the
likelihood of bitter condensed tannins that may remain during aging. Maceration begins
when the grape skins are broken and essentially ‘steep’ in the fermenter, giving reds the
phenol content necessary for taste/mouthfeel/color. Barrel composition (% new French
oak, etc.) can also indicate the influence of hydrolysable tannins, and some winemakers
may even share if they’ve used enological tannins, which are commercially developed
tannins added during fermentation or sur lie. Excessive fining and filtering can reduce a
wine’s aging potential.