What Campden tablets are, why you need them, and exactly how and when to use them at every stage of the winemaking process.
Campden tablets are one of the most misunderstood ingredients in home winemaking. Some people use them at every stage; others avoid them entirely. The truth, as usual, lies somewhere in the middle.
Campden tablets are small compressed tablets containing potassium metabisulphite (or sometimes sodium metabisulphite). When dissolved in liquid, they release sulphur dioxide (SO₂) — a gas that kills wild yeast, bacteria, and prevents oxidation.
One standard Campden tablet contains approximately 0.44g of potassium metabisulphite.
Most fruit you pick or buy is teeming with wild yeast and bacteria. These wild organisms can produce off-flavours, vinegary notes, or simply outcompete your wine yeast and produce something unpleasant. Campden tablets kill them before you add your chosen yeast.
They also protect finished wine from oxidation — the process that turns wine flat and brown.
The 24-hour wait is critical. The SO₂ from the tablets will kill your wine yeast if you add it too soon.
Add half a crushed Campden tablet per 4.5 litres when transferring between vessels. This prevents oxidation and protects against bacteria during the racking process.
Add 1 Campden tablet per 4.5 litres along with potassium sorbate to stabilise your wine before bottling. This prevents refermentation in the bottle.
Campden tablets also make an excellent equipment steriliser. Dissolve 16 tablets in 4.5 litres of cold water and use to rinse your equipment. No need to rinse off afterwards.
Do I have to use them? No. Some winemakers prefer not to use sulphites. However, your wine is at greater risk of spoilage and oxidation without them. For beginners, we strongly recommend using them.
What if my wine smells of sulphur? You've used too much, or racked too early. Splash racking (pouring from a height to expose the wine to air) will usually dissipate excess SO₂ within a few days.
Can I use potassium metabisulphite powder instead? Yes. ½ teaspoon of powder is roughly equivalent to 3–4 Campden tablets per 4.5 litres.
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