I had boxed wine in the refrigerator, then went to a cookout and took it and forgot it in my trunk for a week. Is it still drinkable? It's been in the 90s here in Arkansas.
That would be 90s on the Fahrenheit scale, of course, which corresponds to 32 to 37 Celsius in Canada. So, let's just say your wine experienced its own little cookout.
Is it "drinkable"? Probably, though this will depend on your tolerance for pruny or bruised-fruit flavours. It certainly will be perfectly safe to consume, so no worries on that score. But in all likelihood its taste will have altered for the worse.
Most wines are fragile in that sort of heat. One week is a long time. You must also account for the specific setting, a car trunk. There's no breeze to carry away the increasingly hot air. It's a furnace capable of temperatures higher than 100 Fahrenheit even when the outside air is in the 90s.
Your paint job is a variable, too. It would help if the car were white or light silver, two shades that reflect much of the sun's radiation. (I always make a point of renting white cars when I'm touring and making purchases in California wine country.) Black cars are the worst in these circumstances.
On the plus side, you're talking wine in a box, which should be more forgiving than glass. When wine gets overheated in a bottle, liquid expands upward, pushing up the cork. This causes wine to leak out through the sides of the protruding cork and, in turn, causes air to seep in to fill the void. Excess air in bruises the wine. Boxed wines – also known as bag-in-box – contain a synthetic pouch or bladder. It's more elastic than glass and can more readily accommodate the expanding volume. It's unlikely that air would have seeped into the bladder.
The Flavour Principle by Lucy Waverman and Beppi Crosariol was recently named one of this season's Top 10 cookbooks in the United States by Publishers Weekly. Published by HarperCollins.