Bottle size matters when it comes to wine, but maybe not as much as you might think. That's important to understand if you own larger-format bottles, or are considering buying some.
Conventional wisdom is that smaller bottles age faster than larger ones because smaller bottles have a smaller ratio of wine volume to oxygen, of which there is about the same amount in all bottle formats. That anecdotal thinking has been passed along for decades, becoming one of winedom's golden rules.
Actually testing the theory is more difficult. To begin with, most wineries don't bottle in a wide range of formats. It turns out that the size most people would love to have more of, half-bottles, aren't made by many wineries. Methuselahs, which hold the equivalent of eight bottles and are unwieldy to pour much less decant, are very rare, with correspondingly much higher prices.
Over the past year, I've contacted several wineries about testing this theory and only found one that had a full range from half-bottles to Methuselahs. Moreover, uncorking a Methuselah calls for one of those thirsty special-occasion tailgate-size gatherings. There are other considerations as well. Namely one needs wine with enough age to test the theory.
Chateau St. Jean in Sonoma was the lone winery I found that had a full range of sizes and was willing to open all five, using its 1995 Cinq Cépages, Sonoma County for the experiment. Cing Cépages stands for the five varieties used in its Bordeaux-inspired blend, including Cabernet Sauvignon, Merlot, Cabernet Franc, Malbec and Petite Verdot from a variety of appellations. St. Jean winemaker Margo Van Staaveren and public relations director Nicole Carter hosted and participated in the blind tasting at St. Jean earlier this year. All of the wines had been cellared at St. Jean, meaning none had left the property, an ideal situation since once wine moves around all kinds of variables are introduced.
First we tasted the wines, then we discussed them and guessed which one came from what sized bottle, wondering too whether we could differentiate the wine's development and assign it to a bottle size. We all agreed wine No. 3, which turned out to be the half-bottle (375ml), tasted the most advanced, but only ever so slightly; it's in prime drinking shape and has plenty of life ahead. We also guessed correctly the 750ml, or regular-sized bottle. And we were able to guess the largest, the methuselah. It appeared the most unevolved. But the wine's "maturity" based on bottle size wasn't clear-cut.
All five of the 18-year-old wines were similar—intense, youthful, and identical in color and exhibiting enticing cigar box, olive, road tar, smoke and earth-laced dark berry flavors. When we repoured the wines to refresh them about an hour later, the wines seemed much closer in quality. In fact, the 750ml, magnum (1.5 liter), jeroboam (3 liters) and methuselah (6 liters) were difficult to differentiate.
Three hours later I restaged the tasting in my office, blind again, using wines that had been poured into lab bottles and found it a little easier to pick the wine that tasted the freshest from the one more evolved. But there was one big hitch. The jeroboam was corked. It showed fine in the initial tasting, but later tasted dry and bitter. It had taken a full four hours for the tainted cork character to emerge; when I looked at my notes I'd written during the first tasting I had indicated that the jeroboam had seemed earthier and more tannic, with a more pronounced tobacco leaf edge than the other wines.
Larger bottles are also bottled differently. Magnums at St. Jean are filled with six-spout fillers and corked by hand. Jeroboams and methuselahs are bottled from special tanks and hand corked. Cork sizes increase with bottleneck size. Nearly 12,000 cases of the 1995 Cinq Cépages were made: 375ml ($40 today, totaled 500 cases), 750ml ($75, 11,000 cases), magnum ($160, 110 cases), jeroboam ($400, 110 bottles) and methuselah ($1,000, 28 bottles). St. Jean no longer bottles 375s; the economics of selling half-bottles wasn't worth the trouble for them.
My takeaway from the tasting: If you want to cellar wines, magnums are just the right size.