Along with water, hops, and yeast, malt is the other key ingredient for making beer. Shorthand for malted barley, malts are integral to fermentation and are also responsible for many of those delicious caramel-y, toasty, and fruity flavors we enjoy in a good beer!
Malted barley is made by soaking barley in water to jumpstart germination. This causes starches stored in the barley seed to begin converting into the sugars that the plant will need to grow. These sugars will ultimately be used during the beer-making process to feed the yeast and cause the beer to ferment.
At this point, the malted barley gets roasted and dried for storage. The brewer will later cook the grains in hot water to extract those sugars into the liquid for brewing.
By the way, malts can be made from other grains, like wheat or even corn. Barley is definitely the most common and the most versatile.
Our understanding (and beer buffs, please chime in) is that the malty and sweet flavors in the finished beer are mainly a result of how much sugar is left after fermentation and how the malt barley was roasted. In a very light or bitter beer, most of the sugars were used during fermentation. In a heavy, sweet beer, more sugars are left in the finished beer.
How much maltiness do you like in your beer? Any recommendations?
Related: Gift Idea: Beer Bread Mix
(Image: Flickr members epicbeer and truello licensed under Creative Commons)
TW Salt Mill by Wil...

I've heard that malt extract is used in baking, too, (breads and cookies). I'm game to know more about recipes using malt in non-beer things...
Maltiness is pretty complex, and it not just a matter of sweetness. Basically any flavour that comes from the grain can be a type of maltiness, and can be produced by a very wide range of factors from the malter to the brewer. The type of grain used - even the strain of barley. How long was it malted? At what temperature was it kilned? Was it roasted? (Your used of the term "roasted" in "roasted and dried" is misleading, because not all malts get roasted. In fact, the vast majority do not). At what temperature did the brewer mash (not "cook") the malts? How long and by what means did the brewer sparge the grains (i.e. rinse out the sugars). How long did the brewer boil the wort (the term for "the liquid for brewing")? What yeast was used? And more.
I've taken the same wort from the same brew session and split it into 2 fermenters, and used different yeasts in each one, and the final products can be completely different. One can have very little malt character and the other can be just the opposite.
And bitterness and sweetness (nor maltiness) are not mutually exclusive. You can have a very bitter beer that is also pretty malty or sweet. Though in general malt/sweetness, bitterness, and alcohol are the 3 factors that a brewer tries to balance against each other.
p.s. malted corn is not very popular, but malted wheat certain is in wheat beers. Also popular these days especially amongst small craft brewers and home brewers are malted oats and malted rye.
I like a malty and sweet beer when I'm just drinking a beer, but when I'm eating, I want something bitterer.
Several of the beers that used to be brewed in my hometown (the brewery was Little Yeoman) were known to be fairly sweet and creamy, so maybe that's why I crave them. They were the cream soda of beers! Since moving away I have yet to find anything like them. So please, recommendations!
I've tried the Belgian beer Dikke Mathilde when I was in the Netherlands and that is probably the best beer I've had in my life. Unfortunately, it is almost impossible to find in Canada but I don't know about the States or the rest of Europe.
Like Matchbookhymnal, I also like sweet and creamy beers and I've found that my favorites are Kilkenny, John Smith's Smooth, Tetley Smooth. And those, I can find easily around where I live. They are basically all ales, quite red in colour and without much bubbles.
http://pinternet.net/en/bier/bieren/dynamic-frame.html?http://pinternet.net/en/bier/bieren/strubbe/dikkemathilde.html
there really might not be any better smell than malted grains mashing in your kitchen.
if you're choosing grains for a beer, chew on a kernel or two of the different roasts - they're pretty yummy and you can get a feel for the flavor that will be in the beer.