I agree with Andy's initial assessment, but as Glenn pointed out, "flat" is probably a different descriptor than I would use too. Otherwise, Andy is spot on in my opinion.
Glenn wrote:
While all true in general, I doubt much of that applies to a wine that's been in what's essentially a large oak decanter for 30, 40, or 80+ years. Any oxygen-derived changes that are going to happen to the acidity are going to happen in barrel on an old Colheita... once you put it in glass it's going to be pretty stable for a very long time. Certainly longer than the 5-10 years that some claim causes a bottled tawny to degrade.
First of all, I don't know that we can (or should) describe a TWAIOA (Tawny with an indication of age) and a Colheita the same way in discussions of acidity, in either. Glenn makes an important point to clarify that difference. But let me add a little comparison here.
Tawny Port, or TWAIOA, is a blend. We know by the 10/20/30/40+ indications of age on the label, approximately what the Master Blender perceives has the correct organoleptic characteristics to represent the blend of a Port that old. The acidity, even in a 40 year old Tawny Port will not change that significantly while the components are in neutral oak. It also depends on whether the components are refreshed and or topped off with identical vintage juice, and with regularity. We all know that it is somewhat "cheating" to refresh, but that really applies more specifically to a Colheita, (or definitively with Madeira) while it does remain true as well for TWAIOA.
The acidity in "Colheita" ... all of which comes from a single vintage and remains in wood, (as does frasqueira Madeira) however, if left in neutral pipes for many years, it will certainly change as the Port volume in cask does due to the evaporation, (aka: "angel's share"). As the reduction of the Colheita Port's volume takes place, the acidity within the wine tastes sharper and more accentuated, and if left to further oxidize for too long (untouched), it often times will turn volatile. That's why some producers "might" add younger cask-aged Ports to quickly try to refresh the acidity, which has already ... or may nearly be turning into volatile acidity (or VA).
Some really old Colheitas or Very Old Tawny Ports, may show more sophisticated character by allowing some trace amounts of VA to be intentionally allowed into a Colheita, as an added layer of complexity, in small doses. This is not usually something part of the
recipe, but there are definitely producers that have used this technique in the past, and possibly today as well. Krohn's former owner told me that they never "refreshed" and
always topped off. Some of their Colheitas seemed to taste like, what I described above. Regardless of that, the acidity in a wine bottle, (as Glenn asserted correctly) does not change it's pH level. It may be "perceived" to be more or less sharp, but Madeira offers the best example of this from "old in bottle" vs an older frasqueira (vintage) that hung out in wood for as long as possible, (e.g. D'Oliveiras). In the latter case, you can taste the difference, no question about that.
Niepoort Garrafeira is where Glenn's quote is not 100% accurate, but he was really talking about typical glass wine bottles, not demijohns where there is definitely a significant perceived change in the acidity within those special hand-blown glass vessels. But now we are getting into serious geek territory. Again, I do realize Glenn was talking about wine bottles when he mentioned "glass."
Glenn wrote:
We've been told that you're supposed to drink a tawny as close to its bottling date as possible so that it won't degrade, so that's what people do and what they believe you should do.
In these type of bottles where a TWAIOA, is cellared properly for a lot longer than the original producer ever intended, and then is consumed, there will certainly be a smoother and more dense mouthfeel. But like Andy mentioned, due to how the acidity melds into this dynamic of a wood-aged blended Tawny that has aged for decades beyond what was "intended", for my palate as well, the freshness is lost and while he mentioned "flat" my word would be "tired". Nonetheless, I had a Port exactly like this very recently, with 23 years of bottle age (1996 bottling)
and it was the 20 Year Old (Single Quinta, Bom Retiro) Tawny by Ramos Pinto. It was extremely
interesting and I actually enjoyed it quite a bit. But I did comment to others at the table that it seemed tired and that was when the date on this bottle was then checked. I wasn't surprised. But as Glenn alluded to in his comments on his last post, blind, we all can make the mistake in either direction.
Some people like old-in-bottle Colheitas, I
generally do not. I prefer the fresh, and sharp character of a Krohn 1976 as an example. Or the 2005 bottling of 1952 Dalva Golden White that some of us used to go bonkers for. It is the same reason, I love Madeira. I am an acid freak when it comes to what I enjoy about dessert wines. It is why I rarely find wines like PX (Spanish Pedro Ximenez) too exciting and only can drink a small glass, or enjoy pouring it over coffee ice cream. Your mileage may vary.
Type which appears in red (above) was edited IN, at 2 p.m. Tuesday, after reading what I had written on my break from the newsletter in the wee hours.