What does heat do to wine?
1) Wine can be exposed to very cold temperatures with very few ill effects. The cold can cause the cork to move, thus breaking the seal, this means you need to drink the wine by the next day, not exactly the worst thing in the world.
2) Exposure to excessive heat can “cook” wine, leading to dull, stewed fruit tasting wine. The temperature in your house almost never gets to 120 degrees, so as long as you don’t store your wine on your kitchen window sill, the bottles you have in your house are probably stored in acceptable, if not optimal circumstances. Long term wine storage is a whole other story.
3) On hot days, treat your wine purchases like you would fresh meat or frozen food, do not leave your purchase in the trunk for hours. Hit the wine shop on your way home, get the wine into your air conditioned home where it will be safe.
4) Most of the “cooked” wine you come in contact with is not wine that you mishandled, the vast majority of over heated wine occurs when wine is shipped or warehoused without proper temperature control. If a container of wine gets held up at the docks and an unseasonable heat wave hits, thousands of cases of wine can be affected. That wine will probably make its way to store shelves.
5) Buy wine from shops that are temperature and humidity controlled, cooling costs are very expensive, don’t buy from a shop that skimps in this area. Also, stay away from bottles of wine that are stored near or in the shops front window.
6) But, maybe heat isn’t always detrimental to a bottle a wine. There is a study by a Chinese University that found a bottle of wine that was placed in a microwave and radiated at 420 watts for 5 minutes had a better nose and an improved “overall assessment” than a non microwaved bottle. I don’t think I would try this on a $50 bottle, but a $4.99 Trader Joe’s wine might be perfect for this experiment. Just wait till the wine cools down before you drink it.