I got this from another forum thread:
http://www.tastybrew.com/forum/thread/166472
For my House Crystal..
Soak 2 row in water overnight, about 12 hrs. It'll smell sour, don't worry the heat will drive it off.
Strain and place on a foil covered sheet pan in about a half inch thick layer
Place sheet pan in a cold oven in the top 1/2 of the oven, in mine I put the rack on the highest point.
Turn oven on to lowest setting, in my oven the lowest setting is 175, I wish I could get it to 150.
Let the oven heat up and let the malt "stew" for about 2 hrs. Everytime I think about it I remove the pan and stir the malt a bit.
At this point alot depends on your oven. I have a gas oven therefore the heat isn't as "dry" so the malt is still moist. If it's still moist rearrange the malt so it's in a single layer on the sheet pan, it may take two pans depending on the amount (1lb usaully can be done on one half-sheet pan, 2lb you'll probably need 2 half-sheets or a full-sheet pan). I continue to leave it in on 175 until the malt dries out completely (check by chewing a few pieces, make sure it's crisp).
Once it is completely dry I feel I have a crystal in the 10-20L range. If I want something around 60-80L I crank the oven to 375 and wait about 10 mins. I usually stick around because once I get a slight "toasty" smell, it's done. Leaving it in at this point will get you darker malts, check it often and have some commercial crystal around for comparison.
If you take out the malt once it's dry, then crank the heat and put it back in once the oven heats you can have some more precise control over color. This is just what has been working for me.
I have yet to experiment with temps over 375, but I want to try a short time at 400 and 450 and see what I get.
CE,
As far as I know the wet malt in a cold oven that is heating should essentially "mash" the grain therefore creating sugar, once it dries out that sugar is crystallizing, therefore making crystal malt... at least I think.
edit.
The malt will always taste a bit harsher right out of the oven... aging it for a week or two mellows it a bit.
Besides crystal malt, you can also make the other specialty malts needed for porter, stout, and other styles of dark homebrew. The starting point is your homemade pale barley malt.
To create a reasonable facsimile of Munich malt, simply toast pale malt in a 350° F oven 10 minutes for ounces and 20 to 30 minutes for pounds.
Unfortunately, dark roasted grain must be made outdoors as this process releases a horrendous amount of smoke. Wrap pale malt or unmalted barley in aluminum foil and place over a barbecue grill until the grain is dark brown (not black). Turn often to avoid charring.
I'm sure with some additional searching on the internet will give you a better idea on how to make them.
