How hot is your wine?

October 6th, 2009

Hot wine.

Hot wine.

Don’t you just hate it? That wine shipment you had been anticipating is delivered and when you take it from the driver’s hands, the box is hot to the touch. You dread to think about the temperature of the bottles inside. On such occasions, I have opened the shipper and felt the bottles to be warm.

An informal poll of the delivery drivers who visit my front door indicates that the inside of the delivery vehicle can be about 15°F higher than outdoor temperatures. The temperatures inside the delivery vehicle can reach 100°F when the outdoor temperature is 85°F. The question that begs asking, then, is: Just how hot does wine get inside a shipper if it sits in a hot truck during delivery?

My quest for an answer to this question is a featured article on today.

The instinct of most people is to think that EPS is a far better thermal insulator than molded paper pulp trays. It would be wrong, however, to operate on assumptions without testing them. The results of my experiment raise some concerns.

My test was fairly rigorous, though informal. I welcome feedback. I also encourage others to repeat my experiment or improve on its methodology.

I want to express my appreciation to Tom Mansell – wine blogger and PhD candidate in Chemical Engineering at Cornell University in Ithaca, NY – who did a lot of math to help us understand the possible temperature increase of wine inside an EPS shipper exposed to external temperatures in excess of 110°F. These estimates are also included in the article on To be clear, these are projections. The numbers are the results of mathematical modeling. You can read Tom’s elaboration on how he did the math here.

A study similar to mine was recently conducted by the folks at Vinfolio. The results of this study indicate that overnight shipping in EPS containers – with late afternoon pickup at point of origin and delivery at destination before noon the following day – is likely to be a safe way to ship wines.

Because of the time of day during which the Vinfolio test shipment was in transit, it did not seem to be exposed to the same extreme ambient temperatures as my samples were. While cycling between two extreme temperatures is a commonly accepted mechanism of wine deterioration, I’ve heard it said that wine begins to “cook” (and thus become damaged) once it reaches 80°F. reported maximum temperatures for my zip code to be 83°F on the 27th and 79°F on the 28th of September – the two days I conducted my testing. According to my data and Tom Mansell’s calculation, wine inside and EPS shipper might reach these temperatures when it is transported in a delivery van (without air conditioning) when outdoor temperatures are in the upper 70s.

Furthermore, the post on the Vinfolio blog suggests that the total mass of the wine is protective. The degree – and cost – of that protection is not clearly understood. The wine still has to absorb the heat energy (and in the process, warm up). In a 12-bottle shipper, the bottles around the periphery of the shipper will be most at risk – leaving only two bottles in the central cells most protected (illustration). That is a lot of potentially damaged wine.

It must be pointed out that there is no clear evidence, yet, that the kind heat exposure as described in my experiment damages wines. If these temperature changes do, in fact, affect wines, it stands to reason that we consider if this contributes, in any way, to “tasting room bias“. If it does, there are real implications and consequences for consumers and producers who want their wines to show best with customers and critics.

Two questions remain unanswered:1) does a system like WineAssure result in an increased cost of shipping? and 2) does the weight of the packaging affect the carbon footprint of the wine relative to the other shippers?

Soon, I will conduct some comparative drop testing to see how these different carriers protect wine bottles from impact. Please tune in for those results.


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5 Responses to “How hot is your wine?”

  1. Thomas Pellechia Says:

    Lovely experiment.

    Two things always come to my mind when we talk heat damage:

    1. Wine is an extremely durable liquid. It will fail from temperature problems, but not easily, even if ti expands in the bottle and pushes the cork up.

    2. What did people do about this potential problem before air conditioning, refrigerated vehicles, insulated packaging, and so on?

    I have a feeling they knew about the situation in number 1.

  2. Thomas Pellechia Says:


    Yiou emailed me about Madeira, et al.

    There’s evidence that Madeira’s discovery hadn’t much to do with those sea voyages that people like to romanticize over. The glass-roofed, sun-baking buildings of Madeira pre-date the wine’s transport over the seas.

    Do you select the two words that must be typed to submit a comment? They are often quite humorous.

  3. Dylan Says:

    This is where we need great industrial design. Someone invent a package that is the lightest-weight to date, but positions bottles in the most temperature protected formation–oh, and make it look nice, too.

  4. Soothsayer Says:

    Maybe it should be shipped like this?

  5. grapemaster Says:

    one of the most enjoyable wines i’ve had was an abused bottle of chateauneuf-du-pape, one that had been left in an abandoned warehouse to suffer the ohio extremes of heat and cold. the ullage was up, the color intact, the fruit bruised but present, and all the expectations for a bottle of 1972 wine were exceeded in this bottle of pere caboche chateauneuf. the cork was wet and crumbly, but the wine was intact and delicious despite its past.