Total and free sulphur dioxide

Total and free sulphur dioxide

Sulphur dioxide (SO2) is used as an antioxidant and preservative and has become widely used in winemaking. If it is carefully adjusted prebottling, with attention being paid to the pH and type of wine, the winemaker can ensure that the quality of wine will be preserved on storage.

The EU has set a legal limit for total SO2 of 150 mg/litre in red wines and 200 mg/litre in white wines. However, because some individuals are sensitive to SO2, it is mandatory to include ‘contains sulphites’ on the label if total SO2 is over 10 mg/litre.

‘Free’ SO2 is that which is unbound to compounds in the wine and is therefore able to exert an antioxidant/preservative action. ‘Bound’ SO2 is that which has already been complexed to other compounds in the wine (such as sugars) and has essentially been quenched such that it no longer has antioxidant/preservative activity. Total SO2, is the sum of both of these forms.

Method: Free and total SO2 are determined by either the manual aspiration method or by using the Foss FIASTAR (flow injection analysis).

Amount to send: at least 200ml in full well sealed bottles.

Contact us

If you would like further information or prices please email us at or call our switchboard on +44(0)1386 842000 and they will be happy to direct your call to the relevant person.

Where we refer to UKAS Accreditation

The Campden BRI group companies listed below are both accredited in accordance with the recognised International Standard ISO17025:2017 by the United Kingdom Accreditation Service (UKAS). The accreditation demonstrates technical competence for a defined scope of methods, specific to each site, as detailed in the schedules of accreditation bearing the testing laboratory number. The schedules may be revised from time to time and reissued by UKAS. The most recent issue of the schedules are available from the UKAS website

Campden BRI (Chipping Campden) Limited is a UKAS accredited testing laboratory No. 1079 Campden BRI (Nutfield) is a UKAS accredited testing laboratory No. 1207