Oh, sulphites… If you’ve seen “contains sulphites” on your wine labels and were curious about what they were, this blog is for you. We’re going to do a deep dive into sulphites – where they came from, what they do and why they are in wine.

What are Sulphites?

Sulphites, also known as Sulfur Dioxide (SO2), are a preservative used in wine to help maintain the flavour and freshness. Sulphites are also found naturally in products like black tea, eggs and fermented foods. On top of that, they get added to items such as soft drinks, jams and jellies, pickled fruits and even sausage to help preserve shelf stability or shelf life.

Sulphites have antimicrobial properties which help prolong shelf life of products which is why they are so commonly used.

Sulphites and Wine – Why Are They Paired?

Since Sulfur Dioxide is used as a preservative, it helps keep wine fresh while also maintaining the flavour. Without sulphites, wine could appear brown in colour which can alter the taste. Wine is meant to last a long time and sulphites are used in order to age the wine properly.

Why are Sulphites so Controversial?

Many people commonly associate the dreaded wine headache or hangover with sulphites. In reality, the Food and Drug Administration (FDA) estimates that only 1% of the population is sensitive to sulphites and those headaches could be a result of the actual alcohol content in wine.

If you are someone who is more sensitive to sulphites, experiencing headaches or other effects such as hives or swelling, here are a few things you can do:

  1. Limit your consumption of wine.
  2. Opt for red wine which may have a lower level of sulphites than white wine or ice wine.
  3. Avoid other foods that also contain sulphites as mentioned above. Information will be clearly stated on the label.
  4. Choose a wine with organic or sustainably grown grapes and enjoy in moderation.

A Note From the LCBO

All wines contain some measure of sulphites which form naturally, up 10 milligrams per litre (mg/L), during alcoholic fermentation. 

Sulphites are typically added during the winemaking process and at bottling as an anti-oxidant and preservative.  Any wine sold by the LCBO cannot exceed LCBO’s maximum allowable limits which for most wines are more stringent than Canadian federal regulations.

For dry and medium sweet wines the LCBO’s maximum allowable limit is 50 mg/L.  This increases to 70 mg/L for sweet wines containing more than 35 grams per litre (g/L) residual sugar.

The LCBO Labratory ensures every product you find in-store and online is safe and meets Health Canada’s regulatory standards, including sulfites.



It’s not uncommon to see sulphites in wine. In order to get the taste you know and love without it spoiling quickly on the shelves is to add a preservative in that will extend its lifespan. As mentioned above, some people are more sensitive to sulphites than others. If you are one of these people, take some of the suggestions above into consideration.

PS – Looking for low carb, low sugar and low alcohol wines? Read this.