One of the most famous stout is Guinness (a dry stout to be more precise). I personally don't like much this dry / 'salty' type of stout. I like the sweeter ones, like you were almost drinking a cup of hot chocolate. So, how to bypass the toasty / dryness that the black malts normally provide? Even further, how to add sweetness to it? Thanks!
Traditionally sweet stouts are sweetened by malts and underattenuation in fermentation. In recent times stouts are sweetened by unfermentable sugars like lactose. IE Milk Stout.
I'm not aware of any dark malts that wouldn't provide their characters, in flavor. Though aging does make them more rounded and mild.
... After some conversation on http://hb.chat/ Midnight Wheat seems to be the best for adding color without too many other characters accociated with dark grains.
Like Evil says, you have about three ways to make it sweeter:
- Add non-fermentable sugars. (In addition to the normal stuff, of course) Lactose is pretty usual for this one. I've made sweet stout extract recipes this way.
- Make sure your grain extract has lots of non-fermentables. This might mean mashing at a higher temp, if you are doing all-grain. You could also add things like oatmeal (think oatmeal stout) where the additional body may cause you to perceive it as sweeter.
- Ensure lower attenuation when fermenting. Pick a yeast that is know to be a poor attenuator (think a 'sweet' yeast)
A couple other thoughts: go big: an imperial stout has tons of body, and because it has such a high gravity it often has a lot of residual sweetness.
Try lowering your hopping rate. Less bitter, which make improve the perception of sweetness
I like my home made sweet potato malt ( a recipe from when Costa Rica faced a sugar shortage over 100 years ago).
Cocoa, Black Cherry Extract, molasses, black licorice, English black patent Malt, English Chocolate Malt, Honey, Maple syrup, coffee, coconut...
Lots fun stuff to throw in your porters and stouts.