The first rule is to give it air. Don't just pour and quaff because you are bound to be disappointed. The wine has been deliberately starved of air for years to prevent it from spoiling but the first few hours of oxygen will revive it remarkably. Decant and leave unstoppered for an hour or so and watch the colour and aroma lift. Two to four hours is usually about right. Use an aerator if in a hurry, or pour and swirl vigorously. There is no reliable rule for timing - your nose will tell you. And regardless of whether or not it was filtered at bottling, red wines will throw a crystallised sediment over time. Watch for it as you pour. (Unlike a young wine, however, don't leave it longer than 24 hours once open.)
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