What is Natural Wine?
While there is no official definition of "Natural Wine." It is loosely defined as wine that uses grapes that are grown using organic or biodynamic farming practices which are then hand picked and fermented only using native yeasts found on the vine. The wine is then bottled without filtering or fining with little to no sulphur.
Conventional wines sold in your local shop are not produced using organic or biodynamic farming methods. Some wines tout that they are "Organic" however they are typically high intervention wines that the vast majority use added yeasts to manufacture flavors. There can also be added colorings, sulfites, acid and sugar.
They also can use several different techniques of fining and clarifying agents. Here's where things can get a bit nasty. Winemakers have been known to use Isinglass (Dehydrated fish bladder used as a clarifying agent), Protease (comes from pig pancrease and/or stomach used to which is used remove or eliminate proteins), egg whites used as a fining agent as well as different milk products to manipulate aroma and flavor.
Natural Wine refers more so, to an ancient set of viticulture (grape growing) and winemaking practices and philosophies which were put in place long before the development of the many modern technologies that are used to grow and produce "conventional" wines today.
Viticulture & Oenology
When considering whether or not a wine should be considered "natural" vs "conventional" you have to look at the two sides of the wine's full development, which comes down to two basic questions in regards to natural wine:
1.) How are the grapes grown (viticulture)?
Natural wines are produced using grapes that are grown using strictly organic and/or biodynamic farming practices. The fruit is hand picked, hand sorted and fermented only using only the indigenous yeasts that exist in nature.
2.) What is added during the winemaking (oenology)?
Natural wines are typically bottled without filtering or fining and with minimal added sulphur. These wines typically contain around 10-40 ppm in sulphur while conventional wines have up to 350 ppm.
Now that we have the loose definition out the way we can get into what all of this means. The vast majority of wine you will find in your local shops do not practice organic or biodynamic farming methods. And even if they do, they typically are still high intervention wines that use added yeasts to manufacture flavors.