Potassium metabisulphite Ageing Insurance
May, 2005 Filed in: Wine making
I notice my Winexpert kit instructions tell me to add potassium metabisulphite if I intend to keep my wine longer than 6 months. Why?
Potassium metabisulphite (KMS) is used in wine production to protect wine from being oxidized. The best analogy to this is what happens when you leave a cut apple out on a table. It will quickly turn brown when it is exposed to air. This is known as oxidation. The same thing can happen to your wine. Red wine, when oxidized, will take on a brownish colour which is particularly noticed on the edges of the wine. White wine on the other hand will take on amber to brownish colour when oxidized. The resulting taste is best described as metallic or “tinny”.
Kit makers are faced with a major dilemma. Most wine produced from kits is consumed within 6 months of being bottled. Yet a portion of home winemakers age their wine for longer periods of time. If kit manufacturers put sufficient KMS in the kit to protect your wine for 1-2 years and you open a bottle after 1 month you may likely smell and taste the KMS.
Winexpert, makers of our Vintners Reserve and Selection wine kits take the position of giving you the home winemaker the option and flexibility of choosing the level of KMS in your wine. They provide sufficient KMS to protect your wine for a minimum of 6 months. If you want to age your wine longer, then they advise you to add ¼ tsp. of KMS prior to bottling or at the stabilizing stage. We think this is the best approach. Many other kit makers prefer to “cover all the bases” and put in higher amounts of KMS in their kits. So if you have ever tried someone else’s wine and detected a chemical smell you now know the reason.
You may be interested in knowing that most commercial wine uses 10 times the amount of KMS in their wine versus kit wine due to long storage periods and to cover different storage conditions.
Creative Connoisseur recommends only adding KMS if you are not going to drink your wine within the first 6 months. If you put away your wine for longer periods we recommend adding KMS. So what should you do if you put away say half the batch for long term, and drink the rest within 6 months? You could bottle the first half of the carboy without additional metabisulphite and then add the metabisulphite to the second half of the carboy. Mark the bottles separately so you know which is which.
Potassium metabisulphite (KMS) is used in wine production to protect wine from being oxidized. The best analogy to this is what happens when you leave a cut apple out on a table. It will quickly turn brown when it is exposed to air. This is known as oxidation. The same thing can happen to your wine. Red wine, when oxidized, will take on a brownish colour which is particularly noticed on the edges of the wine. White wine on the other hand will take on amber to brownish colour when oxidized. The resulting taste is best described as metallic or “tinny”.
Kit makers are faced with a major dilemma. Most wine produced from kits is consumed within 6 months of being bottled. Yet a portion of home winemakers age their wine for longer periods of time. If kit manufacturers put sufficient KMS in the kit to protect your wine for 1-2 years and you open a bottle after 1 month you may likely smell and taste the KMS.
Winexpert, makers of our Vintners Reserve and Selection wine kits take the position of giving you the home winemaker the option and flexibility of choosing the level of KMS in your wine. They provide sufficient KMS to protect your wine for a minimum of 6 months. If you want to age your wine longer, then they advise you to add ¼ tsp. of KMS prior to bottling or at the stabilizing stage. We think this is the best approach. Many other kit makers prefer to “cover all the bases” and put in higher amounts of KMS in their kits. So if you have ever tried someone else’s wine and detected a chemical smell you now know the reason.
You may be interested in knowing that most commercial wine uses 10 times the amount of KMS in their wine versus kit wine due to long storage periods and to cover different storage conditions.
Creative Connoisseur recommends only adding KMS if you are not going to drink your wine within the first 6 months. If you put away your wine for longer periods we recommend adding KMS. So what should you do if you put away say half the batch for long term, and drink the rest within 6 months? You could bottle the first half of the carboy without additional metabisulphite and then add the metabisulphite to the second half of the carboy. Mark the bottles separately so you know which is which.