Quick answer
- Sulphites release sulphur dioxide (SO2), which protects wine from spoilage and oxidation and sanitizes equipment.
- Potassium and sodium metabisulphite do the same job. Potassium usually costs a bit more.
- Campden tablets are handy for fruit wine recipes, but powder is better for wine kits because tablets are hard to dissolve completely.
Sulphites have two jobs in winemaking: sanitizing equipment and protecting finished wine. Here is how they work and which form to use.
What Sulphites Do
Metabisulphite is a stable source of sulphur dioxide (SO2). SO2 kills some yeast, mould and bacteria outright and stops the survivors from multiplying.
Added to finished wine, sulphites also prevent oxidation. Oxidized wine is like the cut edge of an apple. It turns brown and tastes flat and “cardboardy”. Without sulphites, homemade wine would need to be drunk within a month or two before it spoiled.
Potassium vs Sodium Metabisulphite
| Potassium metabisulphite | Sodium metabisulphite | |
|---|---|---|
| What it does | Releases SO2 | Releases SO2 |
| Use for | Stabilizing wine and sanitizing equipment | Mostly sanitizing equipment |
| Cost | A little more | A little less |
They are often interchangeable. Many winemakers keep sodium metabisulphite for sanitizing and potassium metabisulphite for adding to wine.
How Much to Use
- Stabilizing wine: your wine kit includes a pre-measured packet. Use it as directed. If you dose it yourself, about ½ teaspoon per 23 L (6 US gal) is the usual guide. Dissolve it in a little cold water or wine first, then stir it in well.
- Sanitizing equipment: 50 g dissolved in 4 L (about 1 US gal) of cold water. See Cleaning vs Sanitizing Winemaking Equipment.
What About Campden Tablets?
Campden tablets are compressed metabisulphite (potassium or sodium). They are easy to use in fruit wine recipes because you just count tablets. For wine kits, powder is the better choice. Tablets are very hard to dissolve completely, which can leave you with the wrong dose.
Safety
- Sulphite solutions have a sharp, ammonia-like smell. Mix them in a well-ventilated area.
- People with asthma or emphysema should not breathe the powder or the SO2 gas from the solution.
- Sulphites can cause reactions in sensitive people. See Sulphites in Homemade Wine: Allergies, Headaches and the Facts.
Frequently Asked Questions
Can I make wine without sulphites?
You can, but the wine will spoil and oxidize much faster. Grapes also produce small amounts of sulphites naturally during fermentation.
How long does sulphite sanitizing solution last?
Stored in a sealed jug, about 5 months.
Can I crush Campden tablets for a wine kit?
You can, but they still dissolve poorly. Powdered metabisulphite is easier to dose accurately.
Need a hand with your batch? Call us toll-free at 1-877-668-6160 (Monday to Friday, 8:00 a.m. to 3:00 p.m. Eastern) or send us a message.
This guide is adapted from the ABC Crafted Series booklet Wine From Kits: What the Instructions Don’t Always Tell You. Always follow the instructions that come with your kit.