I have ghee in clear glass jar on a shelf in my kitchen, would it keep for longer if I try to store it in a dark place? Does light speed up oxidation?
According to IndiaCurry, it should be stored in containers opaque to ultraviolet light for long term storage:
The UV rays from sunlight, florescent lights, and other sources accelerate oxidation process. The storage container container for ghee must be opaque to filter out UV rays. Preferably ghee must be stored in a dark place
I was unable to find credible sources with more detailed information that indicate exactly how this affects storage life. In fact, it was hard to find any references at all--most were far more concerned with keeping it from being exposed to air (oxygen).
However, as it is such an easy thing to arrange--just put the jar in a cabinet for example, or use an amber glass jar--that it seems worth doing. My guess is that in practice, unless you are using your ghee very slowly, or have an extraordinarily large amount, that it makes very little difference, but again its easy, so why not?
I did find lots of references to using ghee in lamps--this is the power of Google! :-)
Did you make it yourself or is it bought?
Ideally ghee and clarified butter should be stored in the refridgerator which is dark by default. Ghee is essentially just butter that has been clarified and has the water and impurities taken out, but sometimes some can remain which is why ideally it's best to keep it in the fridge.
Homemade ghee doesn't need to be stored in the refrigerator.
You can put it in an opaque container and store it in closed cupboard.
Also, the older the ghee is, the yummier and healthier it is.
When making ghee at home, make sure you over cook it a tad bit (this will not alter its taste).
This will ensure that your ghee stays good a longer time, even over a year.
Even slightly undercooked ghee starts giving a foul smell within a month and should not be consumed.
You know your ghee is perfectly cooked when you see it well granulated.