I buy mushrooms regularly from a real expert and here is the advice he's given me with excellent results:
- do not keep mushrooms in a paper bag because they will end up tasting slightly of paper. Keep them in the refrigerator in a crockery or plastic container without the lid on it or they'll get slimy. It could be though that your paper bag has been designed specially for that purpose and wouldn't make the mushrooms taste of paper;
- never freeze raw mushrooms as they'll become horribly mushy and retain water, and believe me, I just experienced this at Christmas: I put a mushroom in my mouth (should have known better as the cook is a darling but really appalling in the kitchen) and the feeling was like biting into a slimy sponge with a large quantity of water then oozing into my mouth (it was a large mushroom). Probably one of the worse culinary experiences in my life.
In other words, cook, then freeze;
- some wild mushrooms you can dehydrate rather easily before putting in the fridge if you need to keep them for a longer period.
Happy holidays to all. :)