Serving wine from a decanter has long been a tradition. Years ago, wine was poured from the bottle into a decanter so that the sediment at the bottom of the would be separated from the rest of the liquid. Because of improvements in winemaking technology, sediment no longer builds in a bottle as it ages. However, decanters still serve an important purpose in the aerating wine. Often wine needs to "breathe" before it is consumed. This means exposing wine to has much air as possible so that the aromatic compounds in the wine are released, which causes a more pleasurable and complex taste. Tannic wines like Barolo, Bordeaux, Cabernet Sauvignon and Port should be aerated, while other more delicate wines like Chianti and Pinot Noir can be harmed by this process. It's important to note that any wine can be spoiled if overexposed to air. Proper aeration is tricky and depends on the qualities of the wine.
Most people are unaware of the difference between decanters and carafes. Decanters have stoppers and carafes don't, because of this, liquids in carafes are more aerated.
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