Organic and organic no-added-sulphur : how to tell the difference
Most wine made from organically-grown grapes contains added sulphur dioxide. Wine made without added sulphur dioxide is comparatively rare. It can be made from organic or non-organic grapes and the wording "no added sulphites" will usually be stated on the front or back label. In the United States, the only wine permitted to be labeled "Organic" is wine without added sulphur dioxide, made from organically-grown grapes. The free and total sulphite content of these wines is required to be less than 10 ppm (mg/l). Tiny amounts of residual sulphites can occur in a no-added-sulphur wine from some strains of yeast used in the fermentation process.

For consumers with a sensitivity to sulphites, the easiest way to make sure that your wine purchase is free of added sulphites is to check the back label. By law, all producers are required to declare the presence of sulphites in their product. Look for the words "Contains Sulphites". 
No-Sulphur-Added Wines (NSA / No SO2 Added)

Notes on No-Sulphur-Added Wines
To make a sulphur dioxide-free wine, it is important to understand why sulphur dioxide is used
in wine in the first place. There are two main areas of application. The first is its role as an
antiseptic. It is used to kill yeast, moulds and bacteria. It is in this role that sulphur dioxide is
used on harvested grapes and in juice before and just after fermentation.
The second is as an antioxidant. It can inhibit enzymes responsible for oxidation. There is a
misconception that sulphur dioxide binds oxygen; it binds the products of wine oxidation.
Modern production techniques and equipment make the use of sulphur dioxide less critical
than in the past. Standards of hygiene in cellars are much improved and the widespread use
of stainless steel makes cleaning much easier. With the selection of healthy, good quality fruit
at optimum ripeness in the vineyard, there is little need to use large amounts of sulphur
dioxide at the start of the winemaking process.
In the 2004 season, the cellar began experimenting with the production of wines to which no
sulphur dioxide was added. Our fifth vintage of no-sulphur-added (NSA) wines has just been
produced, proving that this method of winemaking is a viable commercial proposition.
One must be extra vigilant and attentive to wines made without SO2 While the winemaker
may not add any artificial sulphur to the wine, small amounts of sulphur can be produced
during the fermentation process. Natural yeasts can and do make SO2 but it is very rare for
naturally formed SO2 to be present at bottling above 10ppm.
What prompted the production of a no- sulphur-added wine?
In the organic debate, the United States reserves the label of “Organic wine” for wine made
from organically grown grapes and without any added SO2 and where the SO2 level is below
10ppm. The majority of wines made from organically grown grapes have added SO2 but are
referred to as organic wines. The majority of organic consumers are under the impression that
organic wines contain no preservatives and are surprised to discover that this is not generally
the case. Stellar receives constant queries from the public regarding the availability of SO2
free wines. Producing an SO2 free wine allows us to recapture the credibility in organic wines
while at the same time giving our customers what they want.
What are the benefits?
On the winemaking side the flavours are cleaner and more “transparent”. In red wines the
colours are often better. SO2 can bleach colour.
Shelf life of no-sulphur-added wines
There is a perception that NSA wines have a shorter shelf life that that of conventional wines.
Not all red wines will improve with age. The sulphur dioxide content is not the criterion. The
tannin profile, the extract, pH, acidity and volatile acid level all play a role in influencing the
longevity of a wine. Some wines will last in a bottle but not necessarily improve, others will
improve because tannins are softening and wood influence is integrating into the wine.
Wines need SO2 at bottling to mop up the effects of the dissolved oxygen that gets into the
wine during this process. If this added oxygen is not absorbed into the wine by its tannins and
other antioxidants, the oxygen will generate acetic acid and allow the wine to spoil. In the past
before sterile filtration became the norm, the SO2 killed any stray yeast and bacteria found in
the wine. Today’s bottle rinsers, and vacuum-pulling, gas-sparging bottle filling machines go a
long way to eliminating the problems that made sulphur additions at bottling a strict
requirement.
The shelf life of a wine is thus determined by the style in which it was made and how effective
the bottling process is in keeping the wine sterile and free of dissolved oxygen.
These wines are also made to be bottled quickly and consumed relatively young.
It is a bit of a balancing act to keep a wine full of antioxidant tannins but keep it drinkable
whilst still young. Our trials with wood- influenced So2 free wines are working well. These
wines have a shelf life comparable to conventional wines of the same style and are still
drinking well at the end of two years.
Not all [red] wines are sulphur dioxide-free candidates. There is much that we are still
learning. Generally wines that have a special tannin and colour profile are the best
candidates. This is something that one must discover by tasting and experience. Generally
they are wines with deep colour and rich tannins. Not harsh or astringent tannins. Obviously
the tannin structure makes the wine more robust when challenged by oxygen, but it must not
be so full of tannins that it becomes undrinkable. The introduction of wood to these wines is a
bit of a two-edged sword. On the one hand it would be nice to get the wine safely into the
bottle as soon as possible but to get the richness and complexity that wood brings requires
some time for the integration of the wood and wine. This time makes the wine vulnerable to
oxidation and microbial spoilage. The introduction of wood can also stabilise the colour and
act as an antioxidant. The extent to which this happens is not predictable but must be evaluated in each wine.