Your Wine Questions Answered: Part 5
Deposit in red wine is usually called sediment and most often appears after the wine is fully mature. Some winemakers bottle without any filtration and these wines may leave a deposit on the bottle within the first few years after purchase
Sedimental deposit can arise from several sources. It may be tartaric acid, the predominant acid in grapes, mixed with coloring matter. Or it may be tannin and coloring matter, or anthocyanins that have bonded together and precipitated to the bottom of the bottle. As this process has occurred, the wine has become softer and less tannic, as well as lighter in color as tannin and anthocyanins turn into tiny particles. Concurrently, darkly-colored wines have more anthocyanins to shed and more sediment at maturity. Light-colored grapes such as Pinot Noir rarely have much sediment.
When you see sediment building up in the bottom of the bottle, the wine is exhibiting its complete maturity and may need drinking. Certainly fine sediment is a sign of good storage. It's also important to transport the wine carefully so that the well-stored bottle doesn't become cloudy, and it's necessary to decant the bottle.
If you do need to decant, pour the wine gently into a very clean glass decanter and watch the neck and shoulder of the bottle for chunks of sediment. Stop pouring when the fine sand is beginning to enter the neck of the bottle. Later, when you are desperate for a little more of your great bottle, use cheesecloth to strain the sediment. Avoid coffee filters, which use chemical adhesives to bind their fibers together, and leave a residual taste.