Decanting wine is the process of facilitating oxygen into the wine usually in a vessel other than the bottle in which the wine is bottled in - a decanter.
This process is usually carried out on Bold Italian wines such as Barolo, Chianti, Brunello di Montalcino, Montepulciano d’ Abruzzo also bold oaky Malbecs, shiraz and big French wines such as Merlot and Pinot Noir. Not usually done on white wines however some acidic whites can benefit from it. If you decant a white wine pay attention to its age as it might be subject to faster oxidation if it is an old wine. On average 30 minutes is sufficient decanting time.
Decanting has two main objectives:
Improve taste by allowing some oxidation and separate the sediment from the wine which is usually present in old wines. If a wine is young, most likely you can just pour it into the container until your heart’s content, with older wines you need to be careful to ensure that the sediment at the bottom of the bottle does not get transferred into the decanter.
Zinfandel: 30 minutes
Pinot Noir: 30 minutes (e.g. red Bourgogne)
Malbec: 1 hour
Grenache/Garnacha Blend: 1 hour (e.g. Côtes du Rhône, Priorat, GSM)
Cabernet Sauvignon or Merlot: 2 hours (e.g. Bordeaux)
Petite Sirah: 2 hours
Tempranillo: 2 hours (e.g. Rioja, Ribera del Deuro)
Sangiovese: 2 hours (e.g. Brunello di Montalcino, Chianti)
Vintage Port & Madeira: 2 hours
Mourvèdre/Monastrell 2–3 hours (e.g. Bandol)
Dão and Douro Reds: 2–3 hours
Syrah/Shiraz: 2–3 hours
Nebbiolo 3+ hours (e.g. Barolo, Barbaresco)