I recently made a Wild Mushroom rissotto and towards the end of the process I added the dried mushrooms and cooked them for about 3-4 min and then I let the risotto sit for a little with a lid on. The mushrooms were tuff and had not cooked. Prior to adding the mushrooms, I poured boiling water on them and let sit for around 12 min. Flavor was there!!!!
Question about dried Wild Mushrooms??
I put the mushrooms right at the beginning. So first I sweat an onion, then add my fresh mushrooms, sauté them for a bit, then add the rehydrated dried mushrooms and let them cook for a bit, add the rice, cook, then white wine, stock etc...
If you think of rehydrated mushrooms as the equivalent of fresh, you wouldn't do a risotto and add diced fresh raw mushrooms at the last minute - you'd cook them first, then add the rice - same with the dried stuff.
PS: strain the rehydration water through a coffee filter and use it to cook the rice! Umami!!
DONT BOIL! Let them sit in warm water for about a half hour. You'll have better results and invest barely more time. Like FF said, strain it! I make it my first installation of liquid, and my next ones will be of stock. Before you begin cooking the risotto, cook them in butter with salt and pepper and shallots. It will greatly enhance their flavor. You can even stretch your supply by dicing them and cooking them with diced creminis. Pouch some of those dried mushrooms in olive oil, and you will have an amazing, buttery tasting porchini flavored oil that's a great finishing touch to the risotto and many pastas.
And don't you dare put a lid over your risotto ever again.
Even rehydrated I don't really like the texture of dried mushrooms. I do however use them religiously in my mushroom risotto because the flavor is incredible (I use dried porcinni and chanterelle in addition to fresh mushrooms.) So what I do is rehydrate them like you did, then chop them up very very finely and add them to the onion as it's sweating, before the rice even goes in. The flavor will be there but you can avoid the rubbery tough texture.
The best method I have found that at the end of the cooking process I add a couple of knobs of butter and a bit of parmesan, I put the lid on and leave it for 2 minutes right before serving. Works for me.
I let it rest with my plate over it for a couple of minutes after it comes off the heat, then add the butter & cheese, carry out the mantecatura very violently (most crucial step) and serve.
You'll have to fill me in on what mantecatura means.
Dried mushrooms can be very though... I have had experience with over dried mushrooms which were difficult to cook. First, it's a good idea to live them soaking in water over night and then to change water and boil prior further cooking. Last year I have had very good wild edible mushrooms harvest and I have prepared some dried mushrooms by myself. Since I did it right they require just half an hour of soaking in the warm water prior cooking and they will be soft.
I will agree with French Fries that re-hydrated mushrooms are nothing like fresh. They feel and taste a bit different. And usually you would require more dried mushrooms than fresh for cooking the same dish.
I just love mushrooms!!!