What is sulfite and what does it do in wine?

Sulfites in wine are a topic of conversation. At first glance, I thought it sounded quite similar to the gluten debate, which thankfully seems to have died down a bit. The sulfite hype began when the EU mandated labeling sulfite content if it exceeds 10 mg/l.

What is sulfite and why is it used in wine?

Sulfite is a Preservative . It binds with oxygen, preventing the wine from oxidizing. This is beneficial, as otherwise the wine would turn brown like an apple if you don't eat it quickly. The same thing happens to the flavor. Oxygen also gets involved, turning the wine into vinegar.

In addition, sulfite helps counteract unwanted aromas and kills bacteria. It can therefore also be used as Disinfectant . The observant reader will understand that sulfites aren't strictly necessary for this. Healthy grapes and good hygiene in the wine cellar make sulfites unnecessary at this stage.

What else does sulfite do?

Sulfites are also used to block malolactic fermentation. This is a winemaker's choice. However, malolactic fermentation can be blocked in other ways.

Will sulfites give me a headache?

No, alcohol gives you a headache. Sulfites aren't the culprit here, unless you're hypersensitive and/or asthmatic. A well-made red wine contains an average of 50 mg/l of sulfites, a white wine about 100 mg/l. Dried fruit, such as apricots, contains much more sulfites (see this article ). Otherwise, check if you also get a hangover from it. There is a good chance that No. Is sulfite harmful to health? No, in these quantities it is not harmful (except sometimes; see the reasons mentioned above).

For organic viticulture, the maximum permitted amounts of sulphites are lower.

#nerdalert: sulfite, sulfur, and sulfur dioxide

If you dig a little deeper into sulfite, you'll also encounter other terms like sulfur and sulfur dioxide. In English, the words sound similar, which makes it even more confusing: sulfite, sulfur, and sulfur dioxide. Besides, I'm not a chemistry whiz, so any logic in this completely escapes me. Stay calm and think...

Sulfite (sulphite) is actually a collective term used on wine labels for free sulfur dioxide, sulfurous acid, bisulfite ion, sulfite ion, and some forms of complex sulfite (source: The Oxford Companion to Wine). It's a natural byproduct of fermentation, so every wine contains some sulfite.

Sulphur (S, sulfur, sulfide) Sulfur is a chemical element found in nature. It makes up approximately 0.5% of the Earth's crust. It is very important in wine production and has been used since ancient times as a cleaning and preservative, for example, in the form of resin lining amphorae. Today, it is still used to disinfect oak barrels. In the vineyard, sulfur is used to combat (downy) mildew. Also by organic farmers .

Sulfur dioxide (SO2, sulfur dioxide) is formed when sulfur in the air is burned. This chemical compound is most commonly used by winemakers, primarily as a preservative and disinfectant. Simply put, SO2 reacts with oxygen and prevents oxidation of wine or fruit juice. SO2 can be added during the crushing and/or pressing phase, immediately after harvest – this deactivates oxidation and thus prevents the juice from browning. It can also be added after alcoholic fermentation to block malolactic reaction.

Is there sulfite-free wine?

Nope. Let me explain:

It would be impossible to produce a completely sulfite-free wine, as a small amount of sulfur dioxide is a byproduct of yeast's metabolic activity during fermentation when the fermented material contains sulfate salts. Since sulfate salts are natural components of fermentable materials such as fruit juices, it is normal to find small amounts of sulfur dioxide in fermented products like wine. (Source: The Oxford Companion to Wine)

Get it? In plain language: a wine can't be sulfite-free because a small amount of "natural" sulfite is formed during fermentation. And that's why it says "no" in such a case. added sulfites' on the bottle.

Voila, mystery solved.

Wines without added sulphites

Yes, they do exist, but not all wines are created equal. More and more sulfite-free wines are appearing on the market because it's trendy. Are they inherently good or better than sulfite wines? Absolutely not. The loudest labels are usually the least appealing. Can I say that? Yes, because this is my blog.

Wineries that use the lack of sulfites as their USP forget that it's all about flavor. These wines usually have an oxidative character and smell of apple cider, orange and grapefruit peel, and a blond beer. You can certainly enjoy those, but I'm usually done with them after just one glass.

Of course there are Exceptions . For example, there are wineries that have been committed to minimal intervention for years. They want to make a pure wine, a wine without additives. Or at least with as few additives as possible. That, in my opinion, makes the difference. Not adding sulfites almost never improves a wine, but it's worth considering how little is actually needed. With super healthy grapes, a spotless cellar, and a skilled winemaker, sulfite use can be kept to a minimum. Only a small amount is added at bottling, purely as a preservative. In addition, there are a few winemakers who focus on making wine without added sulfites, such as Frank Cornelissen (Etna). No matter how good the wine may be, it will never become mainstream. James Goode explains in The Science of Wine It turns out that the biggest problem lies in storage. Sulfite-free wines must be kept cool at all times (throughout the supply chain and at the consumer's premises). That's quite a challenge...

Update 2021 ( Decanter ):

“Frank Cornelissen was long famous for his refusal to add sulphites to his Sicilian wines at any stage. By his own admission, the results were mixed. 'Vintages like 2011 and 2014, when the fruit was perfect and all elements of the maturation fell together, are still delicious. Others, like 2005, are like Russian roulette: some bottles are great, others not.' After 20 years, Cornelissen has concluded that the advantages of adding small doses of SO2 outweigh the disadvantages .

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