Marthèlize Tredoux: Decanting dilemmas

eveA recent discussion on this site’s comment section brought up another chestnut of the wine world: decanting. It was nothing new: heartfelt support versus moderate skepticism. It dawned on me that I didn’t really have an opinion either way and concluded that would not be an acceptable state of being, so I looked into the skinny on decanting.

Most people will be vaguely familiar with certain words and terms, flung about often: “sediment”, “softening tannins”, “aeration” and that old stalwart, “allowing the wine to breathe”. But what do they all mean and how much of it is really a thing?

Two reasons to decant wine are unanimously agreed upon. The first is to separate the wine from any sediment that may have formed during ageing. This sediment is usually made up of tartrates and/or tannins and is more prolific in red wines than white. While sediment itself has no negative effect on the wine, it’s not visually very appealing and detracts from the overall aesthetic. This links to the second reason for decanting: it adds a sense of occasion to the opening, pouring and drinking of wine. Nothing wrong with a little pomp and ceremony.

I love decanting wine. It looks good and sometimes the wine just seems to taste better after a few hours in a magical crystal vessel. I’m all for removing it from sediment and I love a bit of theatre when I have guests around. But as for the idea of breathing and the softening of tannins, the jury’s still out.

The story goes that exposing the wine to oxygen for relatively short periods of time (one to four hours) serves to break down the tannins, which in turn softens the wine and improves drinkability. Alternatively, aeration is thought to “open up the wine” by allowing volatile compounds to evolve and become more expressive. Apparently.

The major bugbear for these assertions is the lack of science to back it up. I like to think that wine is equal parts science, art and magic, but the “magic” part is most likely just the things science hasn’t explained yet. Doesn’t make it any less magical, but until the mechanism behind fairy dust is patented, it’s safe to assume there’s some scientific basis in even the most revered of wine mysteries.

The problem with the tannin-softening theory is that chemically, no changes in tannin structure seem to have been observed after decanting. Softening of tannins is generally a result of the process of polymerisation (when small molecules join together to form large ones) of tannin molecules. This process happens over weeks, months and years. It most likely couldn’t happen within a period of hours – not enough to impact the wine on any perceptible level anyway. It’s also questionable whether decanting could even introduce a large enough amount of oxygen to induce tannin degradation.

The idea that decanting “opens up” the wine might be closer to the mark. Exposing wine to oxygen is known to remove sulphur-based compounds like thiols (mercaptans) and hydrogen sulphide – nasty things that cause undeniably disgusting smells (think rotten egg) when present in high concentrations. In lower concentrations, these compounds can still alter the perception of a wine: even though the wine might not smell entirely of skunk, these culprits could suppress more delicate notes, altering the perception of the aroma. Removal of these through exposure to oxygen via decanting can take as little as one hour, leaving the wine with more delicate, vibrant aromas. And if the wine smells better, it probably tastes better.

While science continues to figure it out, in the end – as with all subjective matters – most will rely on personal experience and perception: you don’t really need to ask anyone who’s spent R2 995 on a Riedel Eve decanter what their thoughts on the matter are. Whether or not the efficacy of a decanter correlates with the price thereof is an entirely separate topic.

  • Marthèlize Tredoux is the co-owner and editor at Incogvino. By day, she helps SA wineries sell their wine in the USA. She won a wine writing award once.

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  1. ErichApril 29, 2015 at 12:51 pmReply


    With regards to the “hyperdecanting”, I don’t know if I should admit to it or not, but I have tried it. Out of curiosity I might add.

    In a nut shell: did wonders for the bottle of Tassies I used; ruined the vintage Cab.

    So in short, Marthelize’s assessment is correct. If you want to do it, use the “dry red” you keep around the place for when the mother-in-law is around.


  2. KwispedoorApril 22, 2015 at 10:46 pmReply

    Hi, Marthèlize

    When you write “Two reasons to decant wine are unanimously agreed upon. The first is to separate the wine from any sediment that may have formed during ageing.”, I’m unsure whether you mean that people agree that decanting is a good way to separate wine from its sediment, or if you mean that people agree that the presence of sediment is a reason to decant.

    I’d agree with the former, but the not the latter. I have a decanter, but I use it about once every two years, nowadays – and never for old wines. I also have many wine-drinking buddies and decanting because of sediment is decidedly rare among them. Since it’s mostly old wines that have meaningful traces of sediment, decanting becomes a bit of a Russian Roulette exercise (for me) in the sense that these same gorgeous sedimented geriatrics are the same ones that are often too fragile to be ‘manhandled’ like that.

    I seem to recall someone (perhaps Michael Fridjhon or Dave Hughes) writing many years ago how he was a touch late to arrive for a tasting at one of the Constantia wine farms, where they were tasting a very, very ancient Constantia sticky. As he arrived, the whole shed (or whatever) where they tasted was engulfed by the exotic aromas of this wine, to the extent that he could smell it from a distance. A few minutes later, the glory was gone and the wine had completely died.

    An extreme example that is, of course, but I think there’s generally truth in old wines being more fragile than the more robust young ones.

    Of course I understand that many people enjoy decanting old wines and I’ll even concede that it’s sometimes beneficial. However, I’m someone who prefers to EXCLUDE as much pomp from of my wine drinking as possible – especially when my thirst demands immediate action! Also, I love seeing sediment in my wine. To me it’s not unsightly, it’s beautiful! It’s not only an integral part of the wine, but it helps to tell the wine’s own story. I won’t demand a face-lift and botox – tell me the story, wrinkles and scars and all.

    Disclaimer: I live on the East Rand, where we can be a bit rough around the edges: we didn’t even decant our 1966 KWV Crusted Vintage Port…

    • Marthelize TredouxApril 22, 2015 at 11:30 pmReply

      Hi Kwispedoor

      To clarify your first question: in a sense I suppose both meanings, in a way:
      a) decanting is a good way to separate wine from sediment
      b) the presence of sediment is a reason to decant the wine if your preference is to remove it. I do mention that sediment in itself it’s not a harmful or detrimental to the wine, it just doesn’t look as nice when you take the last sip and you’re left with the visible dregs of tartrate and tannin. Make sense?

      Personally, I’m not bothered by sediment but not everyone around the table are always clued up on what it is – and with perception being such a large part of wine drinking and enjoyment, some people just prefer it to look nicer. To each their own. :)

      As for decanting older wines, I think that if you decant an aged beauty for the specific purpose of separating it from sediment, it most likely doesn’t need to “breathe” for hours, like a younger counterpart might require. So decanting as geriatric is often simply from bottle to decanter and decanter to glass, not really exposing the wine to oxygen . I believe sometimes these wines are decanted to remove sediment, the bottle rinsed and the wine then returned to the bottle immediately, specifically to circumvent the problem you mention.

  3. Ian PirieApril 22, 2015 at 6:25 pmReply

    At a recent wine-making course @ U of Stellenbosch one of the students mentioned a chef friend regularly uses a blender to instantly achieve the effect of several hours of decanting!! Not sure I would have the nerve to ‘blend’ some of my more pricey Bordeaux.

    • Marthelize TredouxApril 22, 2015 at 6:41 pmReply

      Hi Ian
      That’s what they call “hyperdecanting”. I wanted to add something about it in the post but the piece got a bit too long. It’s recently popped up again, but it’s been around on the internet for a couple of years with people putting up videos and blog post about wine in blenders.
      Personally, I haven’t tried it so I can’t comment. I’ve also read a few opinions saying it completely ruins the wine, flattening it and leaving it lifeless. But I don’t really know- I suppose theoretically forcing oxygen into the wine like that could advance decanting effects. I think it’s definitely something for cheaper, sturdier wines. I would not put a beautiful, aged wine in a blender. It just feels wrong – but that might just be me.
      Maybe I’ll sacrifice a few bottles for a blind blender tasting and report back soon. Or maybe someone reading this has already tried it and has some feedback.

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