During wine making sulphur is used as an essential additive as it plays two important roles as an anti-oxidant (prevents enzymatic browning) and anti-microbial (protects against wine spoilage) preservative in its free form. It can have an inhibitory effect on all yeast strains especially ‘wild’ strains as well as effecting malolactic fermentation by MLF bacteria in high doses.
Due to SO2 becoming inactive when it binds with colour pigments of wine and the increased awareness of the effects of sulphites together with the prevalence of sulphite intolerance in some individuals, it has become valuable for wine makers to measure both the free and total SO2. For these reasons, legal limits have been set for maximum permitted levels of SO2 in wines.
In Europe legal limits for Red wines: 160mg/L, White/Rose wines: 210mg/L and Sweet wines: 400mg/L, US legal limits: 350mg/L and Australia 250mg/L. Naturally occurring levels of SO2 in wines are usually found around 10-20mg/L. All wines containing sulphites greater than 10mg/L must have a statement added to the label making the consumer aware that sulphite in present.
As a result of strictly regulated sulphite levels in food and drinks by several governing bodies, Randox Food Diagnostics have developed a test kit available for manual, semi-automated and automated analysers to test total sulphites in wine.
Total sulphite benefits:
• Results within 6 minutes
• Sensitivity of 5mg/L
• Linear to a concentration of 500mg/L
• Excellent recovery across entire analytical range