heated wine corks

Last year around this time, I ranted about shipping wine during the summer, specifically calling out the PLCB for not doing enough to protect the online customer’s wine investments during the warmer months. It is well understood, after all, that extreme temperatures, especially heat, damage wine. But to what extent? How obvious is it to the average consumer when wine has been exposed? How hot does it need to be? I wanted to know more, so I set up an experiment.

My plan was this: secure several bottles of the same exact wine. Keep one cellared, while exposing the others to varying levels of heat. Then, organize a blind tasting to find out if my panel could tell the difference. (Unfortunately, the coffers here at PAVC are not quite the same as say, Wine Spectator, so, despite grand, complex test designs dancing in my head, the experiment had to be run with a limited budget.)

I settled on Perrin & Fils Cotes du Rhone Nature 2010, an $8.99 Chairman’s Selection from a reliable producer and region. Having tried a previous vintage of this wine (I actually paid $14 for it outside of PA!), I knew it was decent enough and that three bottles wouldn’t break the budget.

With two bottles to expose to heat, yet endless variables to play with, I landed on storing both wines in my car’s trunk for the same amount of time (~6 hours or so), but at different temperature levels. The first bottle enjoyed summer’s biggest heat wave, an oppressive 95+ degree day. The second was luckier, doing trunk time on a pleasant day with highs in the low-mid 80s. (The 95+ day was first, so that bottle sat post-exposure for about a week longer than the 2nd bottle.)

Visual Results


The bottle stored at extreme heat (shown on the left; sorry ’bout the blur) was noticeably damaged. When I took it out of my car, it was hot to the touch, there was considerable seepage (wine that had leaked out of the top) and the cork had started to move up the neck.

The bottle exposed to moderate heat (shown middle; looks as high as left but wasn’t) was less obvious. Though the cork had started to come up out of the bottle slightly, it was only lukewarm to the touch and there was no seepage.

It’s also worth noting that I checked this bottle after about two hours and it was still cool to the touch (it had been pulled from the cellar), indicating that short-term storage on a mildly hot day may not expose the juice itself to external heat (due to natural insulation of the bottle glass).

The Blind Tasting

For tasting, I obviously knew the rub, but the bottles were brown bagged and numbered so I could not differentiate. My two co-tasters, Jeff (our “expert”) and Stephanie (our “average consumer”), had no idea what type of wine we were tasting or what the experiment was. After I received their first impressions, however, I did leak the deets so we could all guess which wine was which.

Cellared Wine
At first, this wine showed poorly; its tight aroma and taciturn flavor almost led me to believe it was one of the exposed. Over the 45 minutes that we were tasting and talking, however, this wine evolved noticeably. As it opened, a bouquet of herbs, dark fruits and even a touch of earth emerged.

Moderate Heat (80 degree day)
At first, this seemed like a candidate for the cellared wine, but, unlike that one, it quickly took a turn for the worse. Though fruit-forward and flavorful early on, it fell apart quickly, developing bitter notes and losing aroma quickly.

Extreme Heat (90 degree day)
It was obvious from the start that this was a damaged wine. It had little aroma or flavor, and was sharply bitter on the finish.

The cellared wine was the clear winner; compared to the other wines, it improved considerably as we drank it. Though certainly not a high-end wine, for $9 is a nice value, great for summer barbecues. The moderate heat wine started strong, but actually devolved as we consumed it, finishing limp and flat. The extreme heat wine, obviously, was gone from the start.

Interestingly, we didn’t discover any of the stewed flavors that others sometimes refer to when describing “cooked” wine. Instead, we found the flawed wines to lack aroma and flavor, and to feature a pronounced bitterness at the finish.

Seepage on label


The initial concerns about heat exposure during shipping clearly have merit. There are, of course, many variables at play when you ship a bottle of wine – bottle seal quality, storage container effectiveness, temperature swings during heat exposure, length of time exposed, etc., etc., and we only evaluated one wine on one day. Considering the budget and time restrictions, however, we were able to satisfy our hypothesis within the confines of a limited test.

I for one will continue to exercise great caution when ordering and shipping wine during the summer months, and stand by the assertions last year that Fine Wine & Good Spirits does not do enough to protect web customer shipments during the summer months.

extreme heat bottle with cap on
extreme heat bottle with cap on