Sulfites and Sulfur Dioxide: Labeling in Wine, Beer and Food

What Are Sulfites and Sulfur Dioxide?

Sulfites are salts of sulfurous acid; sulfur dioxide (SO₂) is the gaseous form from which they are derived. Both have been used as preservatives and antioxidants in food production for centuries — most prominently in winemaking, but also in dried fruit, potato products, seafood, and a wide range of processed foods.

Eight different E-numbers are approved for sulfites and sulfur dioxide in the EU: E220 (sulfur dioxide), E221 (sodium sulfite), E222 (sodium hydrogen sulfite), E223 (sodium disulfite / sodium metabisulfite), E224 (potassium disulfite / potassium metabisulfite), E226 (calcium sulfite), E227 (calcium hydrogen sulfite), and E228 (potassium hydrogen sulfite).

Where Do Sulfites Hide in the Kitchen?

Wine is the most well-known sulfite source — but it is far from the only one. Sulfites are present in a surprisingly broad range of products, both as deliberate additives and as natural fermentation byproducts.

Obvious sources:

• Wine — white, rosé, and red wine, sparkling wine, prosecco, cava: virtually all conventionally produced wines exceed the 10 mg/l declaration threshold. White wines typically contain more sulfites than red wines (50–150 mg/l vs. 30–80 mg/l), but both commonly exceed the threshold.

Hidden sulfite sources in food service:

• Dried fruit: Dried apricots, raisins, sultanas, cranberries, and dates — sulfites are added specifically to preserve color and extend shelf life, sometimes at very high levels (dried apricots can contain up to 2,000 mg/kg). The bright orange color of conventional dried apricots is a direct result of sulfur treatment.
• Potato products: Ready-made mashed potato, pre-cut fries, dried potato flakes — sulfites prevent enzymatic browning
• Beer and cider: Both naturally occurring sulfites from fermentation and added sulfites
• Vinegar: Particularly wine vinegar, balsamic vinegar, and cider vinegar
• Fruit juices and preparations: Especially grape and apricot juices
• Seafood: Shrimp and prawns are frequently treated with sulfites post-catch to prevent melanosis (black spotting) — one of the least-known sulfite sources in food service
• Mustard: Some formulations contain sulfites as preservatives
• Processed meats: Sulfites are used as preservatives in some formulations
• Ready-made salad dressings: Wine vinegar as a base carries sulfites
• Gelatin: May have been treated with sulfites during production

Particularly tricky: Sulfites can form naturally during fermentation — in wine, beer, and even fermented vegetables like sauerkraut. Products that have received no sulfite additions can still exceed the declaration threshold if natural fermentation processes have generated sufficient sulfur dioxide.

Transfer Effects: Cooking with Sulfites

Sulfites behave differently in the kitchen from protein-based allergens, and this affects how cross-contamination and transfer risks should be managed.

Wine as a cooking ingredient: When wine is used in sauces, braises, risotto, or marinades, sulfites from the wine transfer partially into the dish. Heating causes some sulfur dioxide to evaporate, but this reduction is incomplete — particularly when the starting wine has a high sulfite content. Extended cooking time reduces sulfite levels, but does not reliably bring a wine-containing dish below the 10 mg/kg threshold if the wine was heavily sulfited. Dishes prepared with wine should generally be assessed for sulfite declaration.

Dried fruit in preparation: Sulfited dried fruit stored or cut alongside other ingredients can leave sulfite residues on shared cutting boards and in shared storage containers through direct contact.

Sulfite-treated shrimp: Shrimp treated with sulfites in shared refrigeration or in mixed seafood preparations transfer sulfites to other products through direct contact and through thaw water.

Correct Labeling on the Menu

Under EU Regulation No. 1169/2011, sulfites and sulfur dioxide must be declared when the final product contains 10 mg/kg or more (solid food) or 10 mg/l or more (beverages). Below this threshold, no declaration is required. This is the only quantity-based exemption among the 14 EU mandatory allergens.

When the threshold is exceeded, the allergen must appear on the menu as „sulfur dioxide“ or „sulfites“ — the specific E-number (E220–E228) does not need to be stated. The declaration must be visually emphasized — bold, italic, or underlined — in the same way as all other allergen declarations.

Wine on the menu: Virtually every conventionally produced wine exceeds the 10 mg/l threshold. The declaration „contains sulfites“ is mandatory for every wine listed — whether served by the glass or by the bottle, and regardless of color or style. This also applies to sparkling wines, prosecco, cava, and wines by the carafe.

Alternatives and Substitutes

True sulfite-free cooking is not always achievable, but meaningful reduction is possible in most kitchen contexts.

For wine: Wines labeled „no added sulfites“ contain no deliberately added sulfur compounds, but natural fermentation still produces sulfur dioxide as a byproduct — typically 5–30 mg/l. These wines often fall below the 10 mg/l declaration threshold, but not always. Organic wines are produced under regulations that specify lower maximum sulfite levels than conventional wines, making them a lower-sulfite option — but not a sulfite-free one. For sulfite-sensitive guests, wine by the glass may remain problematic even with these alternatives.

For dried fruit: Unsulfured dried fruit is available from health food stores and specialty suppliers. It is free of added sulfites — though it develops a darker, less uniform color than sulfited versions (unsulfured dried apricots are brown, not orange). Flavor quality is equivalent. Fresh fruit used as a garnish or component is the safest alternative for sulfite-sensitive guests.

For potato products: Fresh potatoes prepared in-house instead of pre-cut or dried processed products. Enzymatic browning can be prevented by immersing cut potatoes in salted water.

Special Considerations: The 10 mg/kg Threshold, E-Numbers, and Asthma

The threshold rule — the unique feature of sulfite regulation: Sulfites are the only one of the 14 EU allergens where a quantity threshold determines whether declaration is required. All 13 other allergens must be declared regardless of quantity — even trace amounts. For sulfites, products below 10 mg/kg (or 10 mg/l for beverages) have no labeling obligation. In practice, this means: a small amount of wine vinegar in a dressing may or may not trigger declaration depending on the sulfite content of the vinegar and the proportion used. When in doubt, requesting the sulfite content in mg/kg from your supplier is the most reliable approach.

The asthma connection: Sulfite sensitivity is disproportionately prevalent among people with asthma — estimates suggest that 5–10% of asthmatics react to sulfites, compared to approximately 1% of the general population. Reactions can include bronchospasm, breathing difficulty, and anaphylactoid responses. In severely sensitive individuals, inhaling sulfur dioxide vapor — for example when opening a bottle of high-sulfite wine — can trigger respiratory symptoms without ingestion.

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Frequently Asked Questions

At what level must sulfites be declared?

Under EU Regulation No. 1169/2011, sulfites and sulfur dioxide must be declared when the finished food product contains 10 mg/kg or more — or, for beverages, 10 mg/l or more. Below this threshold, no allergen labeling is legally required for sulfites. This threshold rule is unique: all 13 other EU mandatory allergens must be declared regardless of the quantity present, even when present in trace amounts. Sulfites are the only exception.

In practical terms: a product containing 8 mg/kg of sulfites does not require a sulfite declaration; a product containing 12 mg/kg does. Wine virtually always exceeds the 10 mg/l threshold — conventionally produced white wines typically contain 50–150 mg/l, and red wines 30–80 mg/l. Dried apricots and other sulfited dried fruit can contain several hundred to over a thousand mg/kg. When you are unsure whether a purchased processed ingredient exceeds the threshold in your final dish, the most reliable approach is to request the sulfite content in mg/kg from your supplier and factor it into your allergen documentation.

Which E-numbers represent sulfites?

Eight E-numbers are authorized for sulfites and sulfur dioxide in the EU: E220 (sulfur dioxide), E221 (sodium sulfite), E222 (sodium hydrogen sulfite), E223 (sodium disulfite, also known as sodium metabisulfite), E224 (potassium disulfite, also known as potassium metabisulfite), E226 (calcium sulfite), E227 (calcium hydrogen sulfite), and E228 (potassium hydrogen sulfite). All eight are subject to the declaration obligation when the 10 mg/kg threshold is exceeded in the final product.

When reviewing ingredient lists of purchased products, any of these eight E-numbers indicates the presence of sulfites. Their presence does not automatically mean your dish requires a sulfite declaration — that depends on the total sulfite content of the finished dish. For menu labeling purposes, the collective terms „sulfites“ or „sulfur dioxide“ are sufficient; the specific E-number does not need to appear on the menu. This simplifies menu management when multiple sulfite forms appear across different ingredients in the same dish.

Does wine on the menu need to be labeled as containing sulfites?

Yes — virtually every conventionally produced wine contains sulfites above the 10 mg/l declaration threshold and must be labeled accordingly on the menu or wine list. This applies to white, red, and rosé wine, sparkling wine, prosecco, cava, and any wine served by the glass. The format of service — bottled, carafe, or open glass — does not affect the declaration obligation. The label „contains sulfites“ must appear for every wine offered.

Are there sulfite-free alternatives to wine and dried fruit?

Completely sulfite-free wine is practically impossible to produce: natural alcohol fermentation generates sulfur dioxide as a metabolic byproduct, typically producing 5–30 mg/l in the finished wine even without any additions. Wines labeled „no added sulfites“ or „unfiltered, no sulfite additions“ avoid deliberate additions but still contain naturally occurring sulfites. In many cases these wines fall below the 10 mg/l declaration threshold, but this is not guaranteed and varies by producer and vintage. Organic wines are subject to lower maximum permitted sulfite levels under EU organic certification rules, making them a reduced-sulfite choice — but not a sulfite-free one.

For dried fruit, unsulfured varieties are a genuine sulfite-free alternative. They carry no added sulfite preservatives, and their darker, less uniform appearance is the most visible difference — unsulfured dried apricots are brown or dark orange rather than the vivid orange of conventional sulfited versions. Flavor is not meaningfully different. Fresh fruit is the safest choice for sulfite-sensitive guests and can replace dried fruit in most food service garnishes and preparations. For potato applications, fresh potatoes prepared in-house eliminate the sulfite risk present in pre-cut and dried processed potato products — soaking in salted water prevents enzymatic browning without the need for sulfite additives.

Last updated: March 2026 · ChinaYung — Allergen labeling for food service