tag:blogger.com,1999:blog-9216097425984492529.post5693716176888938182..comments2024-03-11T10:03:54.473-04:00Comments on TheWineBlog: "OXIDIZED WINES". Sometimes things are not what they seem...Luiz Alberto, #wineloverhttp://www.blogger.com/profile/16176998729974487627noreply@blogger.comBlogger6125tag:blogger.com,1999:blog-9216097425984492529.post-78230937903701683412012-04-24T02:38:48.565-04:002012-04-24T02:38:48.565-04:00The presence of Acetaldehyde is not the only indic...The presence of Acetaldehyde is not the only indicator of oxidation. More importantly is the whole aroma and flavour profile of the wine. If the fruit aromas are dull and lifeless, that is a good indicator of oxidation in most wines. The timing of oxidation is also important- a wine can be oxidized in barrel, bottled and then move into a reductive state in bottle, which will have a dramatic effect on the flavour profile. Some wines are made "oxidatively" -old style white Rioja for example, but are certainly not oxidized. Oxygen has just been influential in building the flavour profile at certain stages of production.Chris Williamshttp://www.thefoundry.co.zanoreply@blogger.comtag:blogger.com,1999:blog-9216097425984492529.post-30264601124101828932012-04-23T12:54:36.949-04:002012-04-23T12:54:36.949-04:00I think technically you make an interesting point ...I think technically you make an interesting point I don't necessarily disagree with. <br /><br />From a tasting/drinking perspective the issue is simpler to me, especially having a nose with a fairly low threshold for oxidative aromas.<br /><br />For me the question is the age appropriateness of the level of oxidation. Is it in a "normal" range? Advanced? Retarded?<br /><br />This is an important question for my palate regarding many aged wines since I value fruit quite highly, & the vibrant fruit of a high quality wine is usually the first victim of advanced oxidation.<br /><br />This is also obviously not to say that oxidative aromas/flavors are in themselves "bad" - as you stated. <br />I Love aged Sauternes (don't reach their peak until some oxidation has occurred), Sherry, barrel-aged Muscats, Madiera, etc.<br /><br />Just my 2 cents.<br /><br />Cheers, Luiz!Rob Hansulthttps://www.facebook.com/rob.hansultnoreply@blogger.comtag:blogger.com,1999:blog-9216097425984492529.post-90605437804969853212012-04-23T09:12:02.730-04:002012-04-23T09:12:02.730-04:00Luiz - Saw your comment on the Blog. You said - &q...Luiz - Saw your comment on the Blog. You said - "I started this discussion because I believe that wine can taste "oxidated" without undergoing a truly oxidative process (in the sense that the wine was overexposed to oxygen)."<br /><br />In that you are on solid ground - well, somewhat.<br /><br />First we have to agree on what we mean by "oxidized." Usually the textbook perceptual characteristics of "oxidized" are 1) browning, 2) reduced fruit flavors and 3) distinctive aromas/tastes (aldehydes, acetic acid, ethyl acetate).<br /><br />Does having one of those absent the others mean a wine is oxidized, or must all 3 be present to qualify? You've focused only on the presence of aldehydes to be synonymous with oxidized. Maybe that's a bit too restrictive a definition?<br /><br />The reason I say that is because there are various paths to getting one or more of these characteristics at a time. Phenolic/enzymatic as in laccase, chemical (requires a catalyst) and microbiological as in yeast and lactic acid bacteria actions will yield them individually or in combination. All require some level of O2 at some point in the process, but the levels need not be "excessive" nor long lived exposures.<br /><br />Now for the big question - do we care to be so precise in our perceptual definition of oxidized? Well, for judging wines and just detection of a "flaw" probably not. Which makes your observation above right on. But for winemakers the differences in what's seen (the presence or absence of "oxidative" attributes) will mean very different corrective actions.<br /><br />And sometimes we even "oxidize" wines on purpose!Duane Bowmannoreply@blogger.comtag:blogger.com,1999:blog-9216097425984492529.post-88577558545282253602012-04-23T09:00:25.985-04:002012-04-23T09:00:25.985-04:00Tasting "Vin Jaune" from the Jura region...Tasting "Vin Jaune" from the Jura region in France the initial impression of the unfamiliar taster is that the wine is oxidised and faulty. However it is made in a similar way to sherry (but not fortified) and it has a unique and not unattracrtive character once one has accustomed the palate to it. The oxidation is deliberate and gives it it's character. See Jancis Robinson's Oxford Companion to Wine.Anonymoushttp://www.gourmetwinetours.co.zanoreply@blogger.comtag:blogger.com,1999:blog-9216097425984492529.post-52315448676990021992012-04-23T06:23:38.807-04:002012-04-23T06:23:38.807-04:00Hi Richard, thanks for taking the time. Much appre...Hi Richard, thanks for taking the time. Much appreciated.<br /><br />Yes, you are correct. Acetaldehyde is the most important SO2 binder (about 80%), along with pyruvic and 𝜶-ketoglutaric acids.<br /><br />It's also worth mentioning the fact that acetaldehyde is re-utilized by yeast in the second half of the alcoholic fermentation and it is degraded by lactic acid bacteria simultaneously with malic acid during MLF.<br /><br />And that, to a certain degree, acetaldehyde will be used by chemical reactions, such as the one that occurs during red wine aging - polymerization of phenolics.<br /><br />I started this discussion because I believe that wine can taste "oxidated" without undergoing a truly oxidative process (in the sense that the wine was overexposed to oxygen).<br /><br />Are you in agreement with that?<br /><br />Please keep in mind that enology is not my background. I'm just a student trying to put together pieces that will help me and other fellow students of wine to pass their exams.<br /><br />Thank you,<br />LALuiz Alberto, #wineloverhttps://www.blogger.com/profile/16176998729974487627noreply@blogger.comtag:blogger.com,1999:blog-9216097425984492529.post-43210449122355371872012-04-22T21:18:51.437-04:002012-04-22T21:18:51.437-04:00Just to clarify a point here - yes, yeast produce ...Just to clarify a point here - yes, yeast produce acetaldehyde during fermentation. The produced acetaldehyde is usually strongly bound by the sulphur dioxide added after fermentation is complete and cannot be detected on the nose. If oxygen exposure of the wine occurs and SO2 is depleted to a low level, the bound acetaldehyde is liberated and the wine appears aldehydic. So, aldehyde produced by yeast can become apparent due to oxidatve processes that have an impact on SO2 levels. More oxygen exposure can drive further aldehyde production due to conversion of ethanol...a much slower process than SO2 depletion.Richard Gibsonhttp://www.scorpex.netnoreply@blogger.com