Organic wine has officially been around for a very short time (2012). Before, only viticulture was considered and not winemaking. This approach now means that no synthetic treatments and insecticides are added to the vines and has recently proposed reducing (very slightly) inputs during winemaking. Instead, it allows acidification, deacidification, heat treatment, the addition of tannins, the addition of wood chips, sulfur, industrial yeasts, etc.
Biodynamic wine takes the approach of organic wines even further. Vintners using this method try to intensify soil life so that there is a better exchange between the soil and the plant. To do this, they use herbal preparations that they infuse, energize or macerate to help the vine grow stronger and develop better (a sort of homeopathic preventive treatment). They also use the lunar calendar so that plant, soil and lunar influences combine in the best possible way. It was a thinker and philosopher, Rudolf Steiner (1861-1925) who laid the foundations of this movement, also called anthroposophy.
It allows the refining and filtration of the wine, the chaptalization (addition of sugar) only for sparkling wines, but on the other hand the use of a lower dose of sulfur compared to organic wines.
Natural wine therefore combines these two methods but goes even further by not authorizing contributions or techniques aimed at modifying the original must, apart from the sulfur... There is also another section in natural wines even more "until the end", wines without inputs or sulphites.
Below is an example of the difference between these steps:
Conventional red wines EU standards: 160 mg/litre of sulphur
Red wine from organic farming: 100 mg/litre of sulphur
Demeter red wine (biodynamic): 70 mg/litre of sulphur
Red wine Associazione Vini Naturali: 30 mg/litre of sulphur