This was taken from the Wine Expert website:
Winexpert doesn't publish an expiration date for our wine kits, since they don't 'expire,' as such. Our guideline is for users to make their kits in a time period 12-18 months from the packing day, depending on the conditions under which the kit has been stored during that time. Because of their higher brix and acid content, smaller-volume kits (under 15 litres) tend to have a longer shelf-life, while larger-volume (15 litres and over) last for a bit shorter timespan.
It's important to note that the kits don't suddenly stop being viable. They may have oxidised a bit, if storage conditions were not optimal, and this could result in some loss of fruit character or aromatics. But on the whole, they still turn out quite well. In fact, without a side-by-side comparison with fresher kits, most people simply don't notice a difference.
So basically while they say that they don't expire, the suggest that you use them within a certain time frame, that sounds a lot like an expiration date..lol
From the RJ Spagnols website:
Q. What is the shelf life of the kit? How do I know how old it is?
A. On the label that says the type of wine you have is a date code, this is the day the kit was manufactured. The code is simple, YYYYMMDD, so a kit that has 20070214 was made on February 14, 2007. If they are stored correctly 4 week kits will last 18 months, 6 week kits will last 12 months. After that the quality will begin to decline, the juice oxidizes just like wine does.