So why look at a wine before tasting?
Your looking for faults in the wine, checking it is clear and not cloudy. Fill the glass a third of the way, tilt the glass at 45 degree angle so that you can see the surface of the wine from the centre body all the way to the edge, known as the rim. If your tasting a wine blind the wines colour can help with indicating age and grape variety.
In a red wine the darker and more intense colour could show a young wine or a thick skinned grape. A red wine looses colour with age and would start to change from a deep red to a red brick, brown colour and with the glass tilted you can see the change in colour from the middle body to the edge of the rim which could be clear with an old wine.
When we come to white wine the grape will effect the colour and also how the wine was made, whether they used oak or stainless steal. An Australian oaked Chardonnay would normal show a deep yellow golden colour whereas a New Zealand Sauvignon Blanc would give a pale lemon with a hint of green. White wine gains colour with age and deepens and can show a brown tinge.
Who would have thought a wines colour could show so much!