Today when I watched the Uncorked on Amazon, I noticed that Morgan Harris decanted a bottle of 1990 Auslese riesling and he explained the reason behind this is because a lot of old german wine has been sulfured heavily in the past so decanting helps to get rid of the SO2 in the wine and he also specifically suggests to decant old sweet riesling in general.
My question is that since there are two forms of SO2 in the wine, the bound SO2 which dissolved into wine and the free SO2 which helps to preserved the wine and turns into bound SO2 overtime. From my understanding, decanting is helpful for getting rid of the free SO2, which corresponds to the volatile sulfur aroma, but the 1990 riesling has already been aged so I presume a fair amount of the free SO2 has been converted into the bound SO2 already. Does decanting also get rid of the bound SO2 and reveal the aroma? If so, does it also applies to young sweet riesling? Does decanting help to release the aroma in young riesling or it could hurt the tiny CO2 in some riesling and hurt the vibrancy?
I was also wondering if it is a common practice to decant old sweet riesling? I have not done that before but from my limited experience even old riesling turns to be better the next day.
I am looking foward to hear the opinion from the board!
Don’t usually decant, but don’t see a problem with it. I think with a 1990 it doesn’t made a difference. I opened a 1990 Maximin Grunhauser Absberg Spatlase a few nights ago. Wonderful wine without SO2 on the nose.
I can’t speak to the science but I have lots of experience drinking riesling (and other grape varieties) with residual sugar and 20+ years of bottle age and absolutely they greatly improve with lots of air from decanting.
FWIW, Berenice Lurton, the owner of Ch. Climens told me she always decants (and lets the wine warm up from refrigerator or serves at cellar temp).
I cannot speak to the science, but after years of being in a tasting group where certain individuals insisted on pop and pour for older Riesling, I started experimenting and discovered pretty much across the board that Rieslings young and old really demand decanting, or you will miss out on a great deal.
Usually the night before tasting, but sometimes the day of when dealing with 20+ year old wines, I double decant the wine and taste a small sample at the same time. The younger it is, the more aggressively I decant. Then I let the wine sit for 30 minutes and take another small sip to see how much the wine has opened and evolved.
By that point many older wines are unfurling nicely, and I can recork the wine and save it for the tasting. Otherwise I will let the wine sit up to 3 hours before recorking. For a brand new vintage, I will usually allow some decanter time if possible before putting the wine back in the bottle- an hour or so at most. For a recent 2017 Schaefer tasting, the wines were so incredibly backward that I repeated the process twice- but that was a singular event dealing with a singular vintage.
A lot of this process comes with experience and knowing when a wine is starting to open as you expect it should. But for someone starting out, I think double decanting the night before and then decanting at the start of the tasting is a useful simple initial approach until you get more experience.
At that age, I’ve never noticed any overt aroma of SO2 that needed to be released. I am sure it’s for the reasons you gave. I think you’re right that only free SO2 would evaporate out of the wine, and there’s probably not much left. I don’t doubt that there might be other benefits to decanting a Riesling of that age, but I don’t think releasing SO2 is generally one of them.
