What is a Campden Tablet and How is it Used in Brewing?

We explain what Campden tablets are and why you might need them for your homebrewing escapades.


Mat Stuckey

9/1/20232 min read

What is a Campden Tablet and How is it Used in Brewing?

Campden tablets, or potassium metabisulfite tablets, are a common sight amongst homebrewers and winemakers. But what exactly are these unassuming little pills? And what role do they play in fermenting tasty beverages?

What are Campden Tablets?

Campden tablets are commonly used when making fruit wines, ciders, or meads as well as for sanitising fruit additions in beers. They help prevent microbial contamination without negatively impacting brewer's yeast.

These tablets contain potassium metabisulfite, a sulphur-based preservative. Each pressed pellet includes approximately 0.44 grams of potassium metabisulfite in a fast-dissolving form.

When dissolved in liquid, potassium metabisulfite breaks down into two key compounds:

  • Sulphur dioxide (SO2) - Antimicrobial preservative, inhibits wild yeast/bacteria

  • Potassium - Provides nutrient bioavailable to brewer's yeast

The SO2 is where Campden does the heavy lifting in beverage production. At proper levels, it prevents undesirable microbes from multiplying while allowing brewer’s yeast to thrive.

Common Uses for Campden Tablets

Campden tablets have several helpful applications in brewing and winemaking:

  • Sanitising fruit - SO2 prevents wild yeast and bacteria on fruit skins from infiltrating the brew

  • Dechlorinating water - Binds and neutralises chlorine and chloramines prior to brewing

  • Inhibiting vinegar bacteria - Prevents acetobacter that turns alcohol to acetic acid

  • Bottling shelf-stable cider/wine - SO2 prevents refermentation in finished beverages

  • Rehydrating yeast - A tiny pinch of Campden provides nutrients for healthy fermentation

Using Campden Tablets When Brewing

Follow these best practices when using Campden tablets:

  • Use 1 tablet per gallon of liquid or 5-6 tablets for a 5 gallon batch

  • Crush tablet and dissolve fully in a small amount of boiling water first

  • Add Campden solution at least 24 hours prior to pitching yeast

  • Avoid using during active fermentation as SO2 may stall yeast

  • Adjust dosage based on temperature and pH of liquid

  • Limit exposure to direct sunlight which drives off the SO2 gas

Campden tablets help create optimal brewing conditions for the best fermentation results. But use judiciously, as SO2 can develop an unpleasant flavour if overused.

Alternatives to Campden for Homebrewing

While convenient, Campden tablets are not mandatory supplies for brewing. Other options exist:

  • Fruit juicing removes skins harbouring wild yeast/bacteria

  • Boiling fruit or wort pasteurised and kills microbes

  • Frozen fruit discourages microbial growth

  • Sulfite powder dissolves easily if tablets hard to find

  • Yeast health - large starters and ideal fermentation minimise off-flavour risks

With sanitation and healthy fermentation, many styles brew successfully without Campden treatment. But for delicate beers, meads, or wines, Campden tablets remain a useful tool.

So in summary, Campden tablets are an accessible way to leverage the preservative powers of sulphur dioxide in homebrewing. They discourage microbial invaders without harming brewer’s yeast when used judiciously. Understand proper dosing and applications to make these unassuming pills a valuable ally!

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