A couple comments above were spot on and some not accurate.
Micro agglomerated corks are treated once the cork is broken down into particulate utilizing methods that remove tca. Therefore, most (depending on the brand name) should come with a TCA guarantee from the cork producer (namely- CWINE, DIAM, NEUTROCORK etc) and these are therefore, much cleaner than standard whole piece cork (goes for still and sparkling wines).
White vs. Red - The TCA perception on white wines is lower than on reds. This has to do with tannins, oak usage and phenolics of red wines masking what otherwise in a clean fresh white would be perceived as TCA.
Temperature also plays a part. As said somewhere above, many times a wine will just seem “different” but once it sits in the glass for a bit and warms up, the nasty tca starts showing its head more and more as temp rises.
The good news is that today, there are methods to remove tca from cork but unfortunately that does not help the bottles in everyone’s cellar that are 5+ yrs old.
No. Only a handful of cork suppliers - like those you listed - treat the corks that way. Usually they are of very high quality, made of the best raw materials and thus can be (and often are) even more expensive than one-piece natural corks.
However, most micro-agglomerated corks are not treated in any way, are made with cork material of the lowest quality and are usually the cheapest option available. Most of us berserkers see just DIAMs and the like when we see agglomerated corks, but volume-wise those cheap agglomerated corks are much, much more common. The thing is just that any quality-oriented producer won’t touch them.
sorry Otto but you are not correct here. Firstly, I will preface to say that I have spent the last 23 yrs of my life in a leadership role within the cork business. I am very familiar with the 10 or so largest producers who supply more than 90% of the worlds cork. Your comment on only using “the best raw material” is not accurate in addition to “most” not being treated. Micro agglo or fully agglomerated stoppers are always manufactured using the left over of natural cork punching or champagne disc punching or from cork wood that is not high enough quality to make a stopper out of.
With Micro agglomerated stoppers (Neutrocork, DIAM, CWINE, VINC, UNIQ, etc etc) they all use process that remove TCA from cork. In fact, I don’t know a major cork producer who produces a micro agglo that doesn’t have a process that removes the TCA before re-constituting the cork. My company introduced the first proven technology back in 2002 and it has been subsequently copied with and without permission time and again by various producers in Portugal, Spain and France…All better for the industry.
Around 2004 or 2005 OENEO launched a process that uses supercritical Co2 under the brand name DIAM and in 2010 Trefinos (under brand name CWINE) launched the same. If a cork producer doesn’t have a process to remove TCA from cork in micro agglo’s chances are they are bankrupt or very close to. The days of cutting corners in the cork business are over.
I do have to admit that I don’t have such extensive experience with cork business as you do, so I’ll have to take your word for it.
However, having worked for more than half a decade in wine retail, what I noticed that wines that were returned as corked (something we also checked ourselves) were bottled either under regular one-piece corks or cheap agglomerated corks. The problem was even worse with the cheap agglo corks you’d find in traditional French bouché ciders and occasionally with beers bottled under cork (wouldn’t make sense to put a $2 cork to a beverage that retails for $4…). Can’t remember seeing a beverage bottled under a DIAM or other similarly treated “guaranteed TCA free” agglo corks, though - so I guess these work.
However, seeing how I’ve seen hundreds of returns during the time I worked in the retail, many of them under agglomerate corks, it’s hard to imagine all these corks were either pre-2002 or made by companies on the brink of bankruptcy. I really wish virtually all agglomerate corks would be TCA-free, but my first-hand experience is telling me something vastly different.
Finally, aren’t “left over of natural cork punching or champagne disc punching or from cork wood that is not high enough quality to make a stopper out of” two different things? I’ve understood cork is graded by its quality, and I believed leftovers from high-quality cork punching would (or could) produce granules of better quality than cork wood that is of lesser quality (less dense, from portions closer to the ground, etc.). Am I wrong with this assumption? Are all cork granules created equal?
In my experience as an importer there is a vast range of quality in agglomerated corks. Many of them are cleaned using steam, which in some cases leads to whole batches of cork being slightly corked (yes, we’ve had batches of a few hundred cases where every bottle was corked). This is presumably due to insufficient extraction of TCA, leading to averaging the TCA throughout the batch.
Diam is the only safe one, in my experience, and is an excellent choice. Diam always has Diam printed on the side of the cork. For sparkling wines they make a ‘mushroom cork’ called Mytik, that has an ‘M’ on the side. Diam is also consistent in terms of oxygen transmission, which is at least as important as TCA.
There are many others besides diam that are good and offer a tca guarantee with micro agglo. I am not on here to promote my competitors but just give some facts. By way of example - in the USA you have 5 cork companies that are members of the cork quality council. all 5 members represent more than 80% of the cork sold in the US market and all 5 offer a TCA guarantee on the micro agglo’s. if you include DIAM (who is not a CQC member) and a couple others, that number is prob over 95%.
In addition, all micro agglos are going to be consistent cork to cork for OTR as that is inherent to that type of manufactured cork.
The largest suppliers globally are listed below and represent a majority of the worlds cork production.
Amorim (supercrtical process as well as steam distillation process - guaranteed TCA free for both)
OENEO - (supercrtical process - guaranteed TCA free
Bourasse - steam distillation process with a specification on non detectable for TCA
Cork Supply - steam distillation process with a specification on non detectable for TCA
MA SILVA - steam distillation process with a specification on non detectable for TCA
Trefinos - supercritical Co2 process guaranteed to be TCA free
Trescasse - steam distillation process with a specification on non detectable for TCA
Laffite - steam distillation process with a specification on non detectable for TCA
Ganau - steam distillation process with a specification on non detectable for TCA
Now there are suppliers in Portugal/spain/Italy that offer full agglo corks and sell them for very cheap prices utilizing little or no technology/processing methods for TCA eradication but that should represent very very small percentage of supply and the vast majority of such would have most likely gone out of business over the last 5-10 years as the market no longer accepts it.
Ugh…my only bottle of 2015 Jean Claude & Nicolas Fayolle ‘La Rochette’ [Crozes Hermitage] has a mild taint. I had hoped it would blow off, but after a couple of sips over a couple of days, it has gotten worse. And my only two Saran wrap packages are the wrong kind of PVC for ameliorating the taint, even if that is a desperate half measure anyways. Under the flaw, it feels like this would have been a wine of some interest and depth – smoky, meaty, savory.
It feels like I notice TCA in reds more - perhaps because of the ratio of consumption - but also because so many of the whites I consume tend to be screwcapped or DIAM sealed. Those advances have not had wide adoption in traditional French AOC it seems.