Malbec should be served at room temperature. The more structured styles will benefit from being poured into a decanter and allowed to breathe for up to one hour before serving.
Most Malbec from Argentina and Chile is meant to be consumed within two to four years of vintage date. French Malbec is generally longer-lived; although most is ready to drink when released, sturdier examples can age for a decade or more.
Buying (and drinking) an older bottle will typically get you a mellower softer wine with less obvious fruitiness and more herbaceous aromas. A younger wine will offer brighter, juicier fruit flavors and a firmer texture.
Store bottles in a cool, dark place. While it is now common for wine makers to use plastic corks or screw-top closures which may be stored vertically or horizontally, those with the traditional corks should be laid on their sides to keep them moist.