Being here in Asia, I have started thinking again about how wine is stored. Or better said stored while in transit We have many times shaken our heads when seeing wine and beer being mishandled by letting it stand outside of bars and restaurants. The temperature here is almost always above 25C degrees. Most Asian countries are not traditionally wine cultures, so I get it that many do not know how to handle wine. However, should I order wine at all here in restaurants as the risk is quite high that it has not been transported that gently? Is it really that dangerous if a wine stands outside for 30 minutes to an hour? What kind of temperatures can wine take and for how long without being affected? As I could not answer these questions I took some time to read up.
For the avoidance of doubt, I am now ignoring wines requiring long term storage. This post will focus on wines exposure to heat/freezing during a transit process from winery to restaurant.
Exposure to Freezing
Wine is mostly water, but the alcohol in it lowers the freezing point. So depending on how much or how little alcohol percentage is in the wine bottle, the freezing point of the wine is probably around -9C. When wine freezes it expands pushing the cork up. This allows more oxygen to get into the bottle, and we all knows what that results to. yuk.
Exposure to Heat
Exposure to heat is believed to cause adverse chemical reactions in the wine that may lead to a variety of wine faults. The wine may be spoiled or become “cooked” and develop off-flavors that taste raisiny or stewed.
At a glance, there is a limited amount study around this topic. It is a general belief that wine and heat don’t mix. However, some studies show that when the exposure is only for a short term, the wine remains unchanged. For example, a study done at the University of California shows that wine can tolerate temperatures up to 49C for a few hours without being damaged. I hope they are right. Another study done by Butzke and Chacón-Rodríguez (2012) concludes that heat exposure during transit (variation from -13C to 44C) significantly increased the effective bottle age and wine shelf life. The wines age jumped forward om average by 18 months. It’s not certain (nor probable) that the “ageing” due to increased heat exposure would be the same as if that wine were aged for a comparable amount of time at a more traditional storage temperature. It is likely that at least the subtle differences attributable to terroir would be lost.
A Boston based company, eProvenance also conducted a study by monitoring over 5,000 actual wine shipments around the world. Its data shows that about 15 percent of shipments are exposed to extreme heat of 30°C. The study concluded that wine exposed to temperatures over 26C for more than 36 hours showed permanent change to the wines chemical structure. If temperatures increased to 30C, the damage was permanent already after 18 hours. In this study, shipments to China demonstrate the highest amount of exposure to heat, with 47 percent of shipments breaching 30C. On the route from France to China, a heartbreaking 90 percent touched that level.
After reading up I think I can conclude that extreme cold and heat will have an effect and that many shipments to this part f the world are affected somehow. It seems like there is a good chance that wine will be fine standing a few hours in the heat, however it is more the total transit process one should be worried about. Perhaps winter conditions would be at least slightly more beneficial as opposed to the summer, and perhaps Australian wine would also survive better to this part of the world as they have a significantly shorter transit. But who knows.
I am not sure why the results by eProvenance are so poor. It is not like there is no possibility for a cold chain. I have worked in the pharmaceutical industry where companies spend enormous amounts of money on a guaranteed transport temperature of 2-8C. They use special containers (Unicoolers and Envirotainers) and temperature monitoring to follow that the required conditions are met. However, this is not a cheap service. I can believe that many wineries cannot afford that.
There are some cheaper and more reasonable options though, like frigo containers. The electricity powered cool-container is transported door to door, and adds only about 10% on the total transport price. This is similar to the transport we use for our wines when it is hot. Although we avoid shipping anything during the hot summer months anyway. A frigo container can also be used for sea freight.
So where is the problem then? Poor transport handling or cheap wineries/importers. Wherever the blame, it is a shame that it is usually the customer who suffers the most.
Butzke, C.E., Vogt, E.E., and Chacón-Rodríguez, L. 2012. Effects of heat exposure on wine quality during transport and storage. Journal of Wine Research 23(1): 15-25.
K. MacNeil The Wine Bible pg 79-82 Workman Publishing 2001 ISBN 1-56305-434-5