You’ve probably seen the phrase “contains sulfites” on the last can of cider or bottle of wine you drank. But do you know what sulfites are or why they’re used in cider and wine, but not in beer?

Sulfites are compounds that contain the sulfite ion. Sulfur Dioxide (SO2) is the main one produced by and used in cidermaking. Small amounts of SO2 are a normal byproduct of fermentation, and SO2 is added to cider, generally in the form of Potassium Metabisulfite.

It used to be added to empty barrels by burning sticks of elemental sulfur:  “Lay brimstone (sulfur) on a rag, and by a wire let it down into the cider vessel, and there fire it: and when the vessel is full of the smoak the liquor speedily pour’d in, ferments the better!” (John Evelyn’s Pomona, 1664).

Unfortunately we aren’t that cool anymore.

You may be asking, “ok, but why is this in my drink?” SO2 acts in two key ways: as an antiseptic and an antioxidant.

SO2 is added after pressing the juice but before adding yeast in order to eliminate any spoilage organisms, such as bacteria or wild yeast, from growing uncontrollably and ruining the sweet sweet apple juice. This allows the yeast we choose for fermentation to flourish, and therefore better cider to be produced.

As SO2 binds with oxygen, SO2 is also added after fermentation in order to prevent oxidation. This prevents wine and cider from tasting like wet cardboard, which you’ll recognize if you ever left a half open bottle of wine in your fridge for a few too many days before finishing it off.

So why doesn’t beer use sulfites?

1) the boiling that takes place in the brewing process is their antiseptic step, it gets rid of bad bacteria and yeast.

2) beer contains hops, which among other things (such as smelling glorious and adding bitterness) serve as antioxidants.

At this point you may also be asking, “I’ve heard of wine hangovers, is that a thing?” No, it’s not. First off, ‘There is no medical research data showing that sulfites cause headaches.’ Unsurprisingly, drinking too much of anything causes a hangover. Additionally, the amount of sulfites in cider and wine are extremely low compared to other food items (usually below 200ppms, as compared to over 3000 in dried fruit--see chart below).


So the next time you wake up having drunk perhaps one too many ciders or glasses of wine, remember that, given what you learned here, you unfortunately only have yourself to blame.