The very short answer is no, in the strict sense of the term “natural”. Wines never make themselves. The “natural” destiny of grapes is to become ripe, fall to the ground and either be eaten or for the juice in the grapes to start fermenting spontaneously (naturally), turning eventually into vinegar. So, if we define “nature” as that which develops by itself without any intervention, then wine as wine cannot be natural. But of course, those who say they are making natural wines will acknowledge that wine does not and cannot produce itself. Human intervention is necessary but not sufficient for wine to come into existence. Many decisions and actions must be taken by vignerons to help transform grape juice into wine instead of vinegar.
So, the issue becomes: what interventions in the growing of the grapes, the handling of the grapes and influencing fermentation renders the resulting wine something less than fully natural? For many years now, vignerons have come to understand what kinds of fertilizers help the soil provide beneficial nutrients to the vines and which have proven harmful. There is pretty much a consensus that many chemicals cause wine to taste dead and artificial. We call those wines which are made without any addition of herbicides and pesticides “organic”. Many wineries practice organic farming and can be certified as such. A complicated refinement of organics is bio-dynamics which has become more and more prevalent in Burgundy and Alsace, to mention the two areas where the effort has been to get the terroir to be as healthy and bio-diverse as possible. Such interventions are regarded as beneficial both to nature and equally to the quality and health parameters of the wines made under such regimes.
If one looks at the ten year or so history of natural wines in France, it is clear that as a movement, it is essentially a rebellion against the Appellation d’Origine Controlée (AOC) rules and regulations which set parameters for the naming of wines, varietals that can be planted in specific wine growing regions, maximum yields, etc. The loose members of the natural wine movement regard these rules imposed from above as inhibiting the bottling of wines which do not fall in line with these requirements. France has long had a history of legalism and rules against which there have been many rebellions. The philosophical position that rules, regulations, requirements and limitations imposed by society on individuals is both against nature and inherently unnatural has Jean-Jacques Rousseau as its god-father. Rousseau repeatedly argued that there is an implacable conflict between what is “by nature” and what is “by society”. He is the inspiration of every movement which seeks to return to nature from the entirely artificial limits imposed by those in power.
The voluntary members of the natural wine movement believe in a freedom of viticultural practices which is incompatible with the rules and limits imposed by the various AOC regulations throughout the vine growing regions in France. Aside from this freedom-of-choice-and-action inherent to the natural wine movement there is a shared philosophy that natural wines can have no artificial substances added to the soils in which grapes grow and during the fermentation and aging process. For example, no added yeasts to assist fermentation, no acidification or addition of sugar to raise alcohol levels (to be sure, global warming has taken care of this issue!). Perhaps the most vexatious issue for the natural wine movement is the question of sulfites added just before bottling. There is no “rule” forbidding the addition of sulfites among natural wine makers. The purists of course believe that sulfites should not be added. Let the wines stand or fall by their own inherent qualities. A small amount of pre-bottling sulfites is well known to protect wines from bacterial spoilage, secondary fermentation in the bottle and premature oxidation. Nature is vulnerable so why not give nature a little help—especially with something which is natural? More and more growers are making non-sulfite added cuvées. Wine with excellent pH levels and abundant tannins can perhaps do well without added sulfites. But for 20+ years of aging in the case of some red wines? I wish to add one important point: the destiny of almost wines is to get into restaurants and the homes of wine drinkers far away from where they were made. It seems irrational to me not to provide wines with some protections against the slings and arrows of time, travel and variable storage conditions.