At it's essence, natural wine is an attempt to return to a more traditional way of winemaking. But just how traditional do you need to get to be natural? There are some winemakers going back to fermenting their grapes in Amphora, large ceramic jars buried underground, like they used to do in Ancient Greece. Do we have to eschew all technology to make good wine? If that were true I bet the Amish would be pumping out some really good stuff!
Unfortunately, when it comes down to it, natural wine is just another marketing term. The people who make and enjoy these wines would like more people to know about them, so they feel the need to differentiate it somehow from the rest of wine. And along with that comes a certain amount of propaganda too. Natural winemakers become champions of nature and traditional ways, and big businesses using pesticides and synthetic yeasts become anti-terroir oppressors. Just like every other marketing term applied to wine, you can punch it full of holes pretty quickly.
For example, the French Appellation Origine Controllé (AOC) system was set up to tell consumers which wines were better. A Grand Cru is better than Premier, which is better than Vin de Table, and so on. But does it work out that way? No way! There are plenty of Grand Crus resting on their AOC designation making average wine, and there are plenty of crazy talented winemakers doing their own thing in the Vin de Table AOC making amazing juice. And there's no difference with natural wine. It would be great if you could come up with a definition, slap it on the label, and then you'd know you were getting a beautifully cloudy, original wine with real terroir. But alas, that's not the case. People can't even agree on what the term means in the first place.
The term is frought with ambiguity and misunderstanding, but that's just like everything else in wine, so might as well make an attempt. Alice Feiring, one of the most outspoken natural wine proponents, has proposed one here. The idea for her is that the winemaker should make as little intervention as possible into what nature does. And, I must say, in every wine class I took, and every accepted wine book I've read, this conforms to how they say a wine of terroir should be made. It's not the winemaker's job to impose flavors or techniques to make it taste a certain way. The winemaker is supposed to step out of the way to let nature express itself through the wine.
Having said that, when you really look at it, the winemaker has to impose some control. If he (or she) was really non-interventionist, he would just let the grapes grow like crazy, come back in the fall, pick them and let them sit in a barrel until they were ready. The fact is vines don't make good wine left to their own devices. The best wine comes when vines are stressed just enough. They have to think they're dying, so they pour all the energy into their fruit, and thrust their roots deep into the ground, pulling out the complex nutrients and minerals that make just a few potent grapes, which make complex wines. The moment the winemaker decides to prune to reduce the amount of fruit produced, he's intervened.
The person who is usually credited with starting the natural wine movement is Jules Chauvet, a biochemist and négociant who worked in Beaujolais. The chauvet method, as it's been called, is to vinify using carbonic maceration, with dry ice on top of the grapes during fermentation. Dry ice, which is really just carbon dioxide in solid form, is a natural by product of fermentation, so it would be there anyway eventually. The layer of dry ice acts as protection from bacteria, and allows the winemaker to avoid the use of sulfur. There's nothing harmful about it, but does this sound natural and non-interventionist to you? Nevertheless, many natural wines (some of my favorites) are made this way .
Unfortunately, like with everything else in wine, the term natural wine pretty much becomes useless when we try to examine it closely. So if you want to find good wines that express terroir, how do you do it? My answer is, find a good retailer! Or read a lot. Or turn the bottle around and buy by importer. In spite of all the confusion, when you find a person that dedicates themselves to tasting lots of wines and presenting what they think is the best to you, you'll end up tasting some amazingly made wines, each more individual than the next.