It is hard to believe, given this Winter's storms and incessant rainfall, that last Summer we were on the receiving end of an extended heat-wave. Throughout the second half of July, much of August, and early September temperatures soared well above the seasonal average.
Whilst The Society's temperature controlled warehouse in Stevenage, where all our wines are stored, maintained a constant temperature of between 12° and 16° Celsius (within the 'safe'10°-16°C band generally recommended for long-term wine storage), we were concerned that the high ambient temperatures might adversely affect the quality of wines being delivered to members. To satisfy ourselves that our wines were not being subjected to excessive temperatures we carried out a series of tests using a device that tracks temperatures over time. On several particularly hot days we placed three devices inside one of our vans, the first inside the rear section of the van, the second inside a carton in the van, and we also inserted a temperature probe into a bottle inside the carton.
The results clearly demonstrated the insulating effects of the cardboard and glass, slowing the rise in temperature of the wine over the course of the morning. To give an example, on 5th September 2013 when the outside temperature rose to 29°C by early afternoon, the temperatures of wine inside the bottle were as follows:
|* >80% of Wine Society deliveries are made by 13.00
For Society wines that are delivered by third party carriers, the situation is akin to that of the Society vans, with wines being transported overnight from our Stevenage warehouse to temperature-controlled hubs, and deliveries to members taking place the following morning.
The Society's view, which is supported by research carried out by Purdue University in the USA, is that whilst higher temperatures are to be avoided as far as possible, short term exposure (a few hours) of wines to the kinds of temperatures outlined in the above example does not have an adverse effect on the wine's quality or the speed at which a wine will evolve.