Long before the expiration date on my soymilk, I'm having to toss it and buy a new container. I use soymilk only for my morning tea, and it develops this strange metallic and bitter flavor (it may also be astringent, or it might be that it's no longer countering the astringency of my tea, it's hard to tell). When I dumped out the latest such container, it had grainy bits in the bottom as well.
I store it in the door of my fridge, only taking it out in the morning to pour some in my mug; is this not the best way to store it? Is this flavor actually even a result of it going off, or is there some other problem with my soymilk?
The milk in question is Silk Vanilla Soymilk.