Sulphites in cider

Sulphur dioxide has two useful properties at once. It is an antimicrobial, suppressing wild yeasts and bacteria that would otherwise spoil juice or cider, and it is an antioxidant, binding oxygen and the aldehydes that oxidation produces. Very few other single additions do both.

Its antimicrobial effectiveness depends sharply on pH, because only the molecular fraction of dissolved sulphur dioxide is active and the proportion in that form falls as pH rises. This is why cider makers measure pH before deciding a dose, and why the same addition does very different things in a high-acid and a low-acid juice.

Some sulphite is produced by yeast during fermentation itself, in quantities that vary with the strain and the conditions but are usually small. A cider made with no addition can therefore still contain measurable sulphite, which is one reason "no added sulphites" and "sulphite-free" are different claims.

Traditional practice in some regions avoids sulphite entirely, relying on juice handling, temperature, hygiene and the cider’s own acidity instead. Those ciders are more vulnerable to spoilage and to oxidation, which is a trade-off producers make deliberately.

Regulation (EU) No 1169/2011 lists sulphur dioxide and sulphites at concentrations of more than 10 mg/kg or 10 mg/litre, expressed as total SO₂, among the substances that must be declared on the label of a food or drink. The requirement is an allergen-style declaration rather than a warning, and it applies to wine, beer and cider alike.

The threshold explains a common source of confusion. A product without a sulphite declaration is not necessarily free of sulphites: it may contain up to 10 mg/L without needing to say so. Conversely, a product carrying the declaration may contain only a little more than the threshold, or a great deal more; the declaration is binary and does not indicate the level.

Permitted maximum levels for sulphur dioxide in cider are set by additive legislation, and they differ between jurisdictions and between product categories. Codex Alimentarius maintains international standards for food additives that many national regimes draw on. Because these limits change and differ, CiderHQ does not publish a maximum figure.

Sulphite sensitivity is uncommon in the general population. The best-documented group is people with asthma, a proportion of whom experience bronchoconstriction on exposure to sulphites, in some cases at low levels. Other reported reactions include urticaria and gastrointestinal symptoms, and the evidence for these is weaker and less consistent.

The European Food Safety Authority has assessed sulphites as food additives and has published opinions on their safety and on the exposure of the population, including the position of sensitive groups. Those assessments are the appropriate authority for what is and is not established about sulphite reactions.

The persistent popular belief that sulphites cause hangovers or headaches from wine and cider is not well supported. Alcohol itself, congeners produced during fermentation, and dehydration are far better documented contributors, and attributing a headache to sulphites specifically is difficult to justify from the evidence.

Anyone who believes they react to sulphites should raise it with a doctor. Self-diagnosed food and additive intolerances are frequently wrong in both directions, and someone with asthma in particular has a clinical reason to get an accurate answer rather than a guessed one.

Producers who avoid sulphite generally say so, because it is a decision they have made deliberately and at some cost. Terms used include "no added sulphites", "no added SO₂" and equivalents in other languages; these mean that none was added, not that none is present.

Ciders made in traditional wild-fermented styles, and many small-producer ciders, are the likeliest to have been made without addition. This is not a quality claim in either direction: sulphite-free cider carries a higher risk of the faults sulphite exists to prevent, and a well-made sulphited cider is not thereby inferior.

Where the level rather than the presence matters, only the producer can answer, because the label carries a threshold declaration rather than a figure.