If this just isn't working, then plunge the bunch in a bowl of cold water and shake dry or put through a salad spinner. Then place in a loosely wrapped plastic bag or a plastic container in the fridge. If this doesn't help then change your coriander supplier.
This way of storing herbs applies to all the soft herbs such as basil, mint and chervil as well as parsley and Vietnamese mint.
Herbs don't like being stored in a warm place once cut and, if they're damp and hot, they will rot, which isn't good for anyone.
Hard herbs on the other hand can be kept in plastic bags or containers in the fridge. However, the flavour of rosemary and thyme intensifies as it dries so you can tie bundles with twine and suspend upside down in a cool and dry place. Like soft herbs they will rot if left damp.
There's quite a difference between fresh and dried herbs and they're not always interchangeable. Fresh sage, sauteed with chopped walnuts in butter and tossed through thin fettuccine is a thing of beauty. Make the same dish with dried sage from the supermarket and it lacks subtlety, finesse and a lightness of flavour. However, that same dried sage used in a chicken stuffing works wonders - because it's not really subtlety you're after in that case.
To be honest, I bet there are a lot of readers out there who'd be thrilled to know you're having trouble storing coriander as a lot of people just can't eat it. To me it's one of the most refreshing herbs and I can't imagine a life in the kitchen without it, which is perhaps why I shy away from more European flavours.
It lacks the sweet subtlety of basil or the delicate aroma of chervil, but what it has in abundance is good, clean, powerful flavour. I love it shredded, stalks and all as these are also packed full of flavour, and tossed on to tomato and cucumber salad dressed with lime juice.
I also love it mixed with smoked eel and avocado as a filling for an omelette, and I adore it thrown liberally over a roast chicken and kumara. Interestingly, when I first began cooking in Istanbul over 12 years ago, I was amazed that coriander leaves rarely made an appearance in the Turkish kitchen, yet coriander seeds are commonplace. My friends there said that it was just the way it had always been. I've been pleased to see recently it's making an appearance, snuggling in with the often-used dill, mint and parsley.
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