Campden tablets come in two forms (Sodium Metabisulphite and Potassium Metabisulphite). BlueStem Winery stocks the potassium variety mostly because of all the warnings out there about decreasing your sodium intake. Potassium just sounded healthier to me then sodium and we discontinued carrying the sodium variety tablets several years ago.
We stock potassium metabisulphite in two forms, the granular variety and the tablet variety known as Campden tablets.
Campden tablets are just a pre-measured dosage of sulphites (or sulfites) compressed with a carrier (inert material). This measured amount of sulphites makes it much easier for the home winemaker to control the dosage of sulphites (aka sulfur dioxide or SO2) going into the wine must.
Each tablet contains 65mg/L of sulfur dioxide when dissolved into one gallon of wine must (or 13mg/L if one tablet is dissolved in 5 gallons of wine must). Potassium Metabisulphite powder is much stronger than the tablet form and only 1/4 teaspoon of powder added to one gallon of wine must provides 195mg/L of SO2 (or 39mg/L if the 1/4 teaspoon is added to 5 gallons of must).
The purpose of using potassium (or sodium) metabisulphites in wine is threefold: First, it creates an environment where yeasts which were present on your fruit (wild yeasts) cannot survive; second, it helps to inhibit the growth of bacteria which can spoil your wine; and third, it acts as a preservative so that your wine will have a longer shelf life. In addition, sulfites can also be used for sanitizing your equipment, corks, and bottles.
Commercial wine kits typically come with lower dosages of sulphites because the juice used has been pasteurized prior to packaging. However, if you are planning to age your wine for a considerable length of time, it is a good idea to add additional Campden or metabisulphite powder to your wine prior to bottling.
Crush Campden tablets with a pair of spoons (or a mortar and pestle if you have one), dissolve the powder by stirring into warm water. Add a little wine and stir again. If lumps appear, stir until they disappear and pour this liquid into your empty bucket or carboy and then rack your wine on top of the sulphite mixture.
If making wine from backyard fruit it is definitely a good idea to use one Campden tablet per gallon of wine must to clean your wine must. Crush your Campden tablets and dissolve in warm water prior to adding to your juice. Stir and wait 24 hours prior to adding the appropriate yeast to begin your wine fermentation.
Potassium Metabisulphite powder works best for sterilizing your winemaking equipment and your wine bottles because, as described previously, it is much stronger than the Campden tablets. Add one teaspoon of Potassium Metabisulphite powder to a quart of water and use this as your final rinse for your wine making equipment and for your wine bottles.
Campden tablets (in vials of 50 or 100) along with Potassium Metabisulphite powder are available on our website at www.bluestemwine.com! BlueStem Winery stocks winemaking equipment, supplies, ingredients along with both WinExpert and Cellar Craft wine ingredient kits. We also stock all of the equipment, supplies, ingredients and our own line of ingredient kits called BlueStem's Best for the homebrew enthusiast. Whether homebrewing beer or making your own homemade wine, BlueStem has the items you need for a successful hobby.