Sulphuric acid
A strong inorganic acid used in tiny amounts during brewing and cheese-making to keep the process pH at the right level.
What is it?
Sulphuric acid (H2SO4) is a strong mineral acid. In food manufacturing it is a highly dilute process aid rather than an ingredient present in any meaningful quantity in the final product. It is one of the most widely produced industrial chemicals in the world.
What does it do?
It lowers the pH of a liquid or mixture quickly and predictably. In brewing it adjusts mash and liquor pH to the narrow range that enzyme activity and yeast health require. In some cheese-making it acidifies the milk prior to or during curd formation. Because only very small quantities are needed and the acid reacts with the food medium, very little free acid remains in the finished product.
Where you will see it
Most commonly used behind the scenes in beer brewing and in the production of certain hard cheeses. It is rarely listed on finished-product labels because it functions as a processing aid and the residue in the end product is negligible; when it does appear it reads as 'sulphuric acid' or 'acidity regulator (E513)'.
What the science says
Safety at food-use levels
EFSA carried out a full re-evaluation of sulphuric acid and its sulphate salts (E513 to E517) in 2019. Because sulphuric acid is a normal metabolic product already present in the body and the amounts reaching consumers via food are tiny, the panel concluded there was no need to set a numerical acceptable daily intake. No adverse effects relevant to food use were identified.
EFSA re-evaluated sulphuric acid (E513) and its sodium, potassium, calcium and ammonium salt forms and established a group ADI of 'not specified', meaning the panel found no reason to set a numerical limit at the levels used in food.
IARC classification context
IARC classifies sulphuric acid mists as a Group 1 carcinogen, but this classification relates exclusively to occupational inhalation exposure in industrial settings such as lead-acid battery manufacturing. Ingestion of food-grade dilute acid at permitted levels is a fundamentally different exposure route and is not covered by that classification.
IARC assigned sulphuric acid strong inorganic acid mists to Group 1 (carcinogenic to humans) based on evidence of laryngeal and lung cancer in workers with heavy occupational inhalation exposure. The classification does not apply to oral ingestion.
Where it stands with the regulators
Who should be careful
There is no specific group that needs to avoid E513 as a food additive at the levels encountered in food. People with reflux or oesophageal sensitivity who already limit acidic foods or drinks may wish to note that some beers and cheeses made with this process aid are themselves acidic, though the acid from E513 specifically is not the main driver of that acidity. On a label it appears as 'sulphuric acid' or 'acidity regulator (E513)'.
The honest read
E513 is one of the least consumer-visible food additives because it acts during processing and very little survives into the finished product. The IARC Group 1 classification that sometimes appears in internet searches refers to industrial inhalation of acid mist, not to drinking a beer or eating a cheese made with it. The science here is well-established and the regulatory picture is unusually clear: two generations of safety committees have looked at it and concluded no numerical intake limit is needed.
Related additives
Common questions
Is E513 banned in the UK?
No. Sulphuric acid is an approved food acidity regulator in both the UK and the EU, permitted at quantum satis levels in certain food manufacturing processes including brewing and cheese-making.
Does the IARC 'Group 1' label mean E513 in food causes cancer?
No. The IARC Group 1 classification for sulphuric acid applies to occupational inhalation of strong acid mists in industrial workplaces, such as battery factories. Oral exposure via food is a different route entirely and is not what that classification addresses.
What foods contain E513?
It is most commonly used in beer brewing and in some cheese production as a processing aid to adjust acidity. It is rarely present in finished consumer products in any detectable quantity and is not used as a direct ingredient in most retail foods.
Is E513 vegan?
Yes. Sulphuric acid is a mineral (inorganic) compound with no animal origin.
Sources
- EFSA ANS Panel: Re-evaluation of sulphuric acid and its sodium, potassium, calcium and ammonium salts (E513-E517) as food additives, EFSA Journal 2019
- PMC full text: EFSA 2019 re-evaluation of E513-E517
- IARC Monographs Volume 54: Occupational Exposures to Mists and Vapours from Strong Inorganic Acids; and Other Industrial Chemicals (1992)
- IARC Monographs Volume 54: Sulphuric acid mists chapter (inchem.org mirror)
- UK FSA Approved Additives and E Numbers
- EU Regulation 1333/2008 on food additives (Annex II)
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