There's not just physical work, though there's plenty of that - the management of the must (acids, temperature, various yeasts, enzymes, preservatives and so on) requires enormous understanding of what you've got in the grape, what you're trying to do with it, and how you're going to get it there. There won't be much sleep by winemakers for a few weeks!
Over the coming weeks we will try to get a vintage report from as many of our wineries as possible, and publish it here. So check back every now and then. It should be instructive.