Why is my white wine bottle brown? (Or green). 

Have you heard of light strike before? It's not something that is as well known in terms of wine faults, but it can be quite damaging to the wine if it happens. 

The effect it has on wine is to give odours that are sulphurous, such as eggs or dirty drains. In other words not ideal. It's caused when UV light reacts with volatile sulfur compounds in the wine. This is why you will often hear that it's best to leave wine in darker places and why many cellars are built underground. 

Of course there are certain measures you can take to protect your wine. Obviously don't leave it in direct sunlight or near bright fluorescent lighting. And on the winemakers side, choosing a darker packaging such as a green or brown bottle helps too. 

For the most part, and for most people it's not a major concern. After all, most white wines are designed to be drunk young. But if they are suitable for aging then having these measures in place will help protect the flavours in you…