Sodium metabisulphite or potassium metabisulfite is used as a sterilizing agent in wines to kill off all bacteria and yeast present in wines.
Campden tablets are compressed sodium Metdabisulphite and each tablet contains 0.4g of sodium/potassium metabisulphite. We sell it in non-tablet form because you have to break Campden tablets and crush them before use anyway.
Add the sodium metabisulfite according to the recipe (see here-under) and then let the wine air for at least 24 hours before bottling. This would allow the wine to be stabilized and prevents further fermentation.
Sodium metabisulfite is often used together with potassium sorbate for long term preservation of not only wines but also other food/juices.
Sodium Metabisulphite releases sulfur dioxide when dissolved in a liquid. They are added in small doses directly to fresh juices 24 hours before adding yeast. This is to destroy any wild molds and bacteria that may have been on the fruit. It is also used in stronger doses with water as an equipment sanitizer. You can use it to sanitize fermenting vessels, hydrometers, wine bottles hoses or any other glasses, metal, plastic or wood that comes into contact with your wine. One gram of metabisulphite will impart approximately 60 parts-per-million of sulfur dioxide (SO2) to each liter of wine.
To Purify Juice: Add 0.2 g of metabi-sulphite per liter of juice. Pre-dissolve it in a small quantity of water before adding to the juice. Allow the juice to ventilate in an open container for 24 hours before adding yeast. For over-ripe and potentially moldy fruits, double the dosage.
To Sanitize Equipment: All equipment should be cleaned with soapy water first and then add 16g metabisulphite per liter of water. Also add 3g of Citric Acid. Next you will want to sanitize your fermentation vessel by putting in 40 to 70mm of this solution in the bottom of the vessel. Seal the vessel air tight for 60 minutes to allow the fumes from the solution to permeate the inside walls.
At Bottling Time: Add 0.2 grams per liter of wine to preserve its color and flavor and prevent oxidization. It is also recommended at this time to add Potassium Sorbate to eliminate re-fermentation. Bottle immediately after adding.