Using Potassium Metabisulfite to Make Wine

Using Potassium Metabisulfite to Make Wine

Potassium metabisulfite comes with just about every wine kit and is used as an additive even in wineries. This article explores what potassium metabisulfite is and how it works. To learn how to figure out how much to add to your wine check out Adding Potassium Metabisulfite to Wine (includes a calculator). But what does it do? What is it for? Is it safe? Let’s find out. What is Potassium Metabisulfite? Simply put it’s an antioxidant. It slows down the aging, i.e. oxidation, of wine by removing free oxygen suspended in the wine. Oxygen is both harmful and beneficial to wine. It is harmful in large quantities because it rapidly accelerates the aging process. However, wine starved of all oxygen can develop off flavors. The solution? Remove all oxygen suspended in the wine, bottle it, and let tiny amounts back in through natural cork closures. This is what we call micro-oxygenation. Potassium metabisulfite is often called a stabilizer because it serves to prevent spoilage and further fermentation by removing oxygen. However, this serves another purpose it preserves the flavor and color of a wine. An over oxidized wine can taste cooked or flabby (lacking body). Additionally, an oxidized wine turns red wines orange and eventually brown. White wines turn a golden brown color. This additive is available in a powdered form as pictured here as well as in tablets called campden tablets (affiliate links). Potassium metabisulfite may also be used as a sanitizing agent due to its antioxidant properties. How Does it Work? When you dissolve PM (K2S2O5) in water it forms three different compounds, sulfur dioxide, bisulfite, and sulfite. Each of these is able to bond with free oxygen floating around in wine. When this happens the free oxygen is no longer available to be consumed by micro-organisms. The removal of oxygen chokes off most micro-organisms and will prevent them from reproducing. It does not, however, stop a fermentation. Yeast produces alcohol only when forced to live without oxygen but it does go on living. Read this post for more information on the how yeast is used to make wine. By adding potassium metabisulfite after you’ve stopped fermentation completely you can then back sweeten a wine with little risk of rekindling the fermentation of newly added sugar. A Common Misconception Sodium Metabisulfite can be used interchangeably with potassium metabisulfite. While they both have very similar chemical makeups the difference is that potassium metabisulfite leaves potassium behind and sodium metabisulfite leaves sodium behind. Potassium occurs naturally in grapes and is essential to their growth. So adding a bit more potassium to the mix isn’t going to hurt anything. There’s already some in your wine. Sodium on the other hand is not something we want to add to our wine. Can you see yourself pouring table salt into a glass of wine? No. Don’t use sodium metabisulfite. Things to Be Careful of When Using Potassium Metabisulfite There are a few things you should know about potassium metabisulfite before you use it again. First, the compounds it creates can be hazardous to your health in large quantities. SO2 is a toxic gas to breath. It can cause breathing difficulties, swelling, rashes,...

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