Sulfites in Wine: 5 Myths – and What Really Causes Headaches
Sulfites are blamed for headaches after red wine. You hear that all the time. Yet white wine contains more of them – and rarely does anyone complain after two glasses of Riesling. Sulfites are a preservative that protects the wine from oxygen and unwanted bacteria. Some are naturally produced during fermentation. From 10 milligrams per liter, "contains sulfites" must be on the label, and practically all wines in the world achieve this. In fact, 5 to 10 percent of adult asthmatics are sensitive. Here are five persistent myths and what is really known today about headaches after wine.
What are sulfites in wine and why is the notice on every label?
Sulfites, chemically sulfur dioxide and listed as E220 in the additive list, have two tasks in the cellar. First, they bind oxygen so that the wine does not turn brown and taste like stale apple.Secondly, they inhibit vinegar bacteria and wild yeasts that can turn a good bottle into a bad one.
This is not a modern chemical trick. Barrels have been fumigated with burning sulfur for centuries before wine is added. The only new aspect is the declaration: In Switzerland, the note “contains sulfites” must appear on the label from 10 milligrams per liter . On our Portuguese bottles, this often reads as “contém sulfitos” – the same regulation, different language.
The note is an allergen labeling, not a warning. It says: There is something in it that affects a small group of people. It does not say how much is in it. This is where misunderstandings begin.
Myth 1: Sulfites are responsible for headaches after red wine
This is the biggest misconception, and it persists because "contains sulfites" is the only word on the label that sounds chemical. A true sulfite reaction affects the respiratory system: coughing, wheezing, a tight feeling in the chest. Headache is not part of the typical picture.
The more likely culprits are unspectacular. Alcohol dehydrates and is broken down in the body to acetaldehyde, a substance that causes headaches. Additionally, histamine and tyramine, which are more abundant in red wine than in white wine. And the quantity, which no one likes to talk about.
In 2023, a team from the University of California in Davis uncovered an interesting lead. Apramita Devi, Morris Levin, and Andrew Waterhouse showed in Scientific Reports, that Quercetin-3-Glucuronide – a breakdown product of a grape component – inhibits the enzyme ALDH2.Exactly this enzyme breaks down acetaldehyde. If it is slowed down, the substance accumulates, and the head notices it. Accordingly, red wine contains 4 to 93 milligrams of quercetin per liter, white wine only traces up to 7 milligrams. However, one must remain honest: This was a laboratory study on enzymes, not on humans. The authors themselves write that the test on drinkers is still pending.
What practically helps: drink water in between, eat something, and watch the alcohol content. A wine with 13 percent delivers noticeably less alcohol per glass than one with 15. Our wines from Dão and Beira Interior almost all range between 12.3 and 13.3 percent – not for dietary reasons, but because the high altitudes there have cooler nights.
Dry red wine from Dão.Dry red wines require the smallest dose of sulfites because their tannins naturally combat oxygen.
Myth 2: Red wine contains more sulfites than white wine
It's the opposite. Red wine brings its own protection: tannins from skins and seeds are natural antioxidants, so the winemaker needs less sulfur. White wine lacks this buffer and is dosed higher. Sweet wines are at the top, as residual sugar is food for yeasts and bacteria. Without strong protection, a sweet bottle will eventually continue to ferment happily.
The EU's legal maximum values – according to which every Portuguese wine is produced – reflect this precisely.What actually ends up in the bottle is significantly lower in practice:
| Wine Type | EU Maximum Value | Usual Practice |
|---|---|---|
| Dry Red Wine | 150 mg/l | 40 to 80 mg/l |
| Dry White Wine, Rosé | 200 mg/l | 60 to 120 mg/l |
| Wine with Residual Sugar, Red | 200 mg/l | depending on sugar content |
| Wine with Residual Sugar, White | 250 mg/l | depending on sugar content |
| Noble Sweet Specialties | 300 to 400 mg/l | 150 to 300 mg/l |
So, anyone looking to avoid sulfites by switching from red wine to a semi-dry white has miscalculated.The path leads in the other direction: dry, red, ready.
Fernão Pires, Malvasia, and Arinto from granite soils. Produced dry, without residual sugar that would require additional protection.
For sweet wines, the opposite is true. A Moscatel or a Port wine needs more protection than a dry Douro. That's why you drink a dessert glass of it, not half a liter.
The proof of the rule: residual sugar needs protection. Vintage 2016, dried fruit and orange peel, a small glass after the meal.
Myth 3: There is wine completely without sulfites
There is not. Yeast produces sulfur dioxide during fermentation, without any intervention from the winemaker. Even in a natural wine, where nothing has been added, there are 3 to 10 milligrams per liter. Therefore, such a bottle is correctly labeled as "without added sulfites" and not "sulfite-free."
Those who significantly reduce the addition take a risk: The wine oxidizes faster, is more susceptible to off-flavors, and is less forgiving of transport and storage. This can be fantastic if the grape material and cellar hygiene are right. And quite the opposite if not. You can see how quickly oxygen works with every open bottle in the fridge.
And because it is regularly asked: Organic regulations set lower sulfite limits than general wine law.Organic means less, not zero.
Myth 4: Nowhere else contains as much sulfite as wine
A 0.75-liter bottle of dry red wine contains a total of about 30 to 60 milligrams of sulfite. For dried fruits, the legally permitted maximum amounts vary between 500 and 2000 milligrams per kilogram, depending on the type of fruit. A handful of dried apricots can therefore provide more sulfite than the entire bottle of wine next to it.
It is reassuring how rarely the limits are exceeded: The CVUA Stuttgart found an exceedance in 3 out of 184 dried fruit samples examined between 2020 and 2025. Sulfites are also found in vinegar, dried potato products, dried vegetables, and some seafood.
If you get a headache after two glasses of red wine but can consume a bowl of dried apricots without issue, you may have chosen the wrong suspect.
Myth 5: Many people cannot tolerate sulfites
The group is small and quite clearly defined. According to the German Federal Institute for Risk Assessment, 5 to 10 percent of adult chronic asthmatics react to sulfites with varying intensity. In the general population, the proportion is significantly smaller. Those affected usually notice it in the respiratory tract or through skin reactions such as hives.
Regarding the amount: In 2016, the European authority EFSA set a guideline value of 0.7 milligrams of sulfur dioxide per kilogram of body weight per day. This value was withdrawn in 2022 because the data was insufficient for a clean derivation. This is not an alarm signal, but scientific honesty: We know less precisely than we would like to.
A tip: If you're really sensitive, don't buy the more expensive bottle, but the drier one. Dry red wine and dry rosé will take you further than any label with the word "natural" on it. All our wines contain sulfites as a matter of principle.
The lightest wine on this list. Dry, well-chilled, and with 12.3 percent, the friendliest candidate for a long evening.
Frequently Asked Questions
Do sulfites in wine cause headaches?
For most people, no. A true sulfite reaction affects the respiratory system, not the head.For headaches after wine, alcohol, acetaldehyde, histamine, and the amount consumed are the more obvious explanations. Research from Davis in 2023 also points to quercetin as a possible contributor – so far, however, only in the lab.
Which wine has the least sulfites?
Dry red wine. Its tannins have antioxidant properties, so in practice, 40 to 80 milligrams per liter are sufficient. Dry white wine and rosé have higher levels, sweet wines the highest.
What does "contains sulfites" mean on the label?
That the wine contains more than 10 milligrams of sulfur dioxide per liter. This is an allergen labeling for sensitive individuals and applies to practically every wine, even very good ones. More about the other information on the bottle can be found in our article about the Portuguese wine label.
Is there wine completely without sulfites?
No.Yeast itself produces 3 to 10 milligrams per liter during fermentation. Bottles without added sulfites are correctly labeled "without added sulfites."
How do I know if I am intolerant to sulfites?
Typical symptoms include breathing difficulties, coughing, or skin reactions shortly after consumption, often also after sulfite-containing foods like dried fruits. If suspected, it should be clarified and not answered in the wine aisle.
Where can I buy dry Portuguese wine in Switzerland?
At Vall'doAido , everything is stored in the Swiss warehouse and shipped immediately. We import directly from family businesses in Portugal, from Dão through Beira Interior to Douro.
Dry, authentic, from Portugal
Over 120 wines in the range.Most between 12 and 25 francs.
To the wine selection →All in Swiss stock, ready for immediate delivery. Free shipping from CHF 250.
- Dry Red Wine: 41 red wines in the selection, from CHF 12.00
- Dry White Wine: 41 white wines, from Vinho Verde to Encruzado from Dão
- Sweet Wine and Port Wine: 25 port wines and two Moscatel, for the glass after dinner
Bottom line: Sulfites are to wine what the cork is to the bottle, and for most, they are not an issue. If your head greets you the next morning, it is almost always due to what else is on the label – the alcohol content. And how often it was refilled.