In pretty much all wine-producing countries, there are regulations to limit the sulphite content of wine. The limits are always expressed nominally in terms of total sulphur dioxide, but I suspect they all assume an analysis method that fails to account for some of the bound sulphur dioxide, as discussed in my previous post.
Let’s start by taking a look at sulphite limits in the European Union. The rather complex set of limits are very nicely summarised in a table in the document EU rules for organic wine production: Background, Evaluation and Further Sector Development:
If you feel motivated to check these various EU limits or get more details, the table provides you with the relevant document numbers, which can be found by a web search. But it is not a task to be tackled lightly – I once set out to extract the various sulphite limits from the 1999 regulations and nearly lost the will to live.
The US regulations on the other hand have the advantage of simplicity: for wines with no organic-credentials the limit is 350 ppm (or mg/l – the units are practically identical). That figure is widely quoted, but I am afraid I have not been able to track down the actual regulatory document. I had more success with finding an authoritative-looking document for organic wines in the USA: Organic Wine: Oversight, Labeling & Trade. That document covers two categories: wine made with organic grapes and organic wine, where organic wine has stricter rules. For organic wine, added sulphites are not allowed at all – though the wine will still contain naturally occurring sulphites, and probably need a sulphites warning on the label, as discussed in my previous post. However, for wine made with organic grapes sulphite additions are allowed, providing there is no more than 100 ppm sulphur dioxide in the finished wine. In the EU by the way, wine made with organic grapes is not a special category: the grapes must be farmed organically as claimed, but all winemaking regulations are as for conventional wines in the above table.
For allowable sulphite levels in other countries, The Oxford Companion to Wine reads: “In South Africa, the limit is 150 mg/l for dry reds, 160 mg/l for dry white, rosé, and sparkling, and between 200 and 300 mg/l for sweet wines depending on style and level of sweetness. Argentina: 130 mg/l for dry reds, 180 mg/l for dry white and rosé wines and sweet reds, 210 mg/l for sweet white and rosé. Chile: 300 mg/l for all dry wines and 400 mg/l for sweet wines.”
As far as biodynamic wine is concerned, Demeter certifies it internationally, and their document Standards for Demeter/Biodynamic Wine regulates the use of sulphites. The stated aim is that sulphur dioxide be restricted to the absolute minimum, but then the document proceeds to specify limits that are more lax than the US organic regulations. For different types of wine, the maximum allowable total sulphur dioxide at bottling in mg/l is:
But what about so-called natural wines? As you probably know there is no official definition or certifying body, but we can take a look at the list of wines made by the accredited growers and makers of Raw Wine – Isabel Legeron’s platform for the promotion of natural wines. By searching the list using filters provided on the website, it is possible to get a feeling for sulphite levels in wines deemed to be natural. The database also records which wines have added sulphites, but sadly you cannot use that as a search criterion. Here are the results of a search on 6th June 2019:
|Total sulphur dioxide (ppm)||Number of wines|
I think some of the quoted sulphur dioxide analysis results in this table need to be taken with a pinch of salt. For example, when you look at the data in more detail it is obvious that some testing laboratories round the concentrations to the nearest integer multiple of 5 or 10 ppm. Note also the high number of wines with precisely zero sulphites, despite it being commonly stated that fermentation necessarily creates sulphites in all wines. I have seen 10 ppm referred to as a detectable level, implying that measuring anything less than that is problematic, so perhaps that explains all the wines at 0 ppm? But regardless of such quibbling, I think we can conclude from the table that most natural wines contain less than 40 ppm, and that there are fewer and fewer natural wines at levels increasing from 40 to 70 ppm.
So now we know the sulphite concentrations in some natural wines, thanks largely to sulphites being one of the obsessions of the natural wine community, but getting sulphite concentrations for wines in general seems to be more difficult. The assumption is often that the makers of cheap wines zap their wines with as much sulphite as they can get away with, to compensate for poor fruit quality, and for closer control of the winemaking process to create a consistent product that meets an expected flavour profile. On the other hand, higher quality producers are expected use less sulphites, as they take more care to select healthy fruit, are willing to put more effort into low-intervention winemaking, and are also more tolerant of variation in the end product. I personally think there must be some truth in that characterisation, but sadly cannot demonstrate it with numbers. More certainly, it is the case that red wines need less added sulphites than white, because the tannin in red wines will also provide protection against oxidation, and sweeter wines will tend to need more added sulphites, because the sugar binds sulphur dioxide, rendering it a lot less effective.
To get some feeling for typical sulphite concentrations in wines that are not claimed to be natural, I think we could do a lot worse than look at the maximums in the first table of this post. EU regulations are typically designed to reflect existing practice rather than to effect change, so I think it is reasonable to assume that most wines have sulphite levels approaching, but comfortably within, the specified limits for the different styles of wine. On the other hand, producers who particularly favour low-intervention methods (even if they do not identify with the natural wine movement) would be closer to around 30 ppm, and other high-quality wines would have intermediate concentrations.
So what are we to make of all this? To be honest I am not at all sure. One might hope that maximum sulphite levels were specified according to some sort of objective assessment of health risk, but I am not convinced we know enough about sulphite allergies to do that – there is not even agreement about what proportion of people are affected by sulphites (as mentioned in my previous post). So what we have are rules based on a mish-mash of current practice and ideology. In my opinion, the best that can be said for the current situation is that consumers can exercise a degree of choice about their exposure to sulphites – based on their world-view and how they personally perceive health risks.