Sulphur in wine, what’s the big deal?

Now let’s just get this out of the way at the very beginning. Nothing that I am trying to convey here is anti ‘natural wine’. I have people I consider friends who make natural wine. There are wines that I consider ‘natural’ that I love.


If I have an issue at all it would be this. The appropriation of the word ‘natural’. I don’t think it’s entirely fair because by default there is the inevitable implication that anyone who doesn’t take the same approach is doing something ‘unnatural’.


That is probably a different conversation that what I’d like to talk about today.


Disclaimer aside, it is also necessary to remember that the Natural Wine Movement (NWM) is not one homogenous block of people thinking exactly the same, taking exactly the same approach. There is a general consensus around using wild yeasts, minimal use of additives such as sulphur and minimal human intervention with the fermentation process.


(To be honest, I would say that all my winemaking friends in New Zealand are minimal intervention, because the thing is intervention costs money!)


Of these, it seems to me that sulphur, or the compound SO2 (used interchangeably for the purposes of this article) in particular, gets the most attention. In print or in certain wine bars and magazines. In some NWM circles SO2 is right up there with the devil himself.


As I said, my purpose here is not to take shots. Personal preference is paramount. My reason for writing these words is to inform opinion, to help get information I believe to be relevant into the public conscious. I’ll admit straight up that without access to all the most up-to-date statistics I’m being pretty loose with some of the numbers. I’ve tried to err heavily on the conservative as much as possible, but I think the gist of the pattern is what it’s important to be aware of.


And that is this – If you suffer from wine intolerance, or have a problem with certain wines, it is highly unlikely sulphur is the reason.


(In fact, according to the research paper of newly accredited Master of Wine, Sophie Parker-Thomson, controlled use of sulphur will likely help with your wine issues.)1


‘But people are messed up by sulphur, right?’


Yes. This is totally true.


Some people.


And research shows that it is a very small proportion of the population. In fact, only 3 – 10% of severe asthmatics are allergic to sulphur. To clarify, that’s not 3 – 10% of the total population, or even of the population with asthma. It’s 3 – 10% of severe asthmatics. This reaction is, except in extremely rare cases, limited to respiratory difficulties.


I.e. SO2 messes with breathing.


Prevalence varies country to country, but the WHO estimates there are roughly 300 million asthma suffers worldwide. This would suggest in a population closing in on 8 billion we’re talking less than 4%. Severe asthma is estimated to effect between 5 – 10% of that 4%.


And according to the research 3 – 10% of the 5 – 10% of the less than 4% have a severe reaction to sulphur. Or, in other words, less than 0.001% of the global population (rounded up).


This is just as well. SO2 is used in many, many, many, things because sulphur is the only natural or synthetic chemical that is food grade, antioxidant, and antimicrobial.


We are talking juices, dried fruits, sausages, pickles, vinegar, canned beverages,… the list is extensive. Why is it used? Because SO2 preserves flavours, stabilises, and protects from microbial spoilage.


In fact, perhaps the only place I am aware of where the use of SO2 is heavily controlled is in the fish industry.


If you think that you are one of those who are negatively affected by SO2 then try this simple experiment. Can you drink coke? Can you drink processed orange juice? Can you eat dried fruit? Because all of these things contain SO2 in levels many times what you’ll find in wine.


Even the cheap stuff.


Disclosure. I have a problem with sulphur. At high enough levels I will have difficulty breathing, to the point where I’m pretty sure if I kept going with what I was consuming I’d end up in full anaphylaxis.


I have never had that reaction from wine. Mass-produced pickles? Yes.


Second disclosure. I consume a lot of wine.


Third disclosure. I own a New Zealand wine bar in Japan.


It is worth noting that New Zealand has a disproportionately high level of asthmatics. It is also very worth noting that the NWM, a movement that generally promotes zero sulphur additions as being a better way of doing things, has not really taken off in New Zealand the way it has in Europe, the USA and Japan. The argument could be made that if sulphur really was the devil then with the level of asthmatics in NZ it would a stronghold of low or zero SO2 wines.


Here in Tokyo (in a far from scientific survey) I’ve had multiple guests say they only drink Natural Wine because they are allergic to SO2. After being told that in general NZ wine is very clean of additives compared to some of the mass-produced bulk plonk pumped out from some places, they have then proceeded to drink a glass of something kiwi with seriously trepidation, trusting me but clearly wondering why.


I’ve pressed and been told they get terrible headaches, hang overs, flushes, and sneezing attacks when they drink ‘normal’ wine. Don’t forget, these symptoms are not associated with SO2. When it does cause problems, SO2 messes with breathing.


When these guests have returned they’ve told me that, to their surprise, they felt fine the next day.


Personally, I’m all for minimal intervention. I’m all for protecting the vineyard by promoting biodiversity and the minimal use of dangerous chemicals. But it’s not like I’m an outlier in this idea. Martin Bell, chief winemaker at Butterworth Estate in Martinborough, confirms that this attitude is prevalent. ‘We have a lowest common denominator theory in NZ,’ he told me. ‘If a market doesn't want X in a wine, then X is added to none. I am too small to make three different blends of things. I might as well not add it.’


The NFM began in the Beaujolais region in France in the 1960s. A group of winemakers felt what they were seeing in the market had little or nothing in common with what they remembered from their youth, the sort of wines their ancestors had produced and consumed throughout the years, before the introduction of mass-production processes, pesticides and synthetic chemicals.


This group set about to take things back to basics. To reiterate, I am in total agreement with the sentiment. Soulless, bulk-produced, multi-regional wines that have no character or sense of place miss the mark on what wine should be, in my opinion.


The fixation on SO2 of the modern proponents of natural wine is what I question.


It could be said that the genesis of the NWM came about as a reaction to mass-produced wines made more in a lab than in the vineyard and winery. In general, the majority of New Zealand producers seem to have decided that quality is where they will focus their attentions, and leave the quantity production to countries with a landmass and topography better suited that model.


Could that be the reason why the NWM hasn’t really taken off in New Zealand? The average quality was high enough that the push-back was unnecessary?


Perhaps a subject for another day.


Now that we have gone through these late couple of pages, let’s introduce the real kicker.


SO2 occurs during grape fermentation.


All wine has SO2.


Even wine that claims it has ‘Natural’ zero SO2 has SO2.. (If a wine has somehow had the SO2 removed through some kind of scientific process, it could hardly call itself ‘natural’.)


If you love a natural wine that’s great. Personal preference is paramount. Whether you like a wine is literally the only thing that is important as far as I am concerned.


My suggestion is not to let dogma or dubious marketing trick you into making SO2 into the scapegoat.





1. Sophie Parker-Thomsons research paper ‘What is the relationship between the use of sulphur dioxide and biogenic amine levels in wine? is available for download on the Master of Wine website https://www.mastersofwine.org/rp

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