Malting

Malting is the process of allowing grain to germinate and then drying it before it can sprout. The process involves soaking the grain, allowing it to sit for several days, and then heating it in a kiln to halt the growth process.

Germinating the grain begins the process of breaking the starches in the grain down into sugars. For the brewing process, this is important because yeast can't digest starch, but can digest sugar--breaking it down into alcohol and carbon dioxide.

Additional flavour can be created in the malt by doing various things to it before kilning--some is heated or stewed to begin caramalization, changing the sugars from yeast-friendly to human-pallet-friendly. Others are roasted like coffee, to give a darker, toasted colour and flavour.

Esters

Any of a class of organic compounds that react with water to produce alcohols and organic or inorganic acids. Fairly volatile, in brewing they tend to have a fruity or spicy aroma. Generally produced in large quantities by ale yeast or hefeweizen yeast.

DMS

Dimethyl Sulfide--(CH₃)₂S--is an organic compound containing sulphur. In beer it produces a pronounced "cooked vegetable" flavour and aroma, similar to cooked corn. Usually considered an"off" flavour, except by Rolling Rock who consider it desirable. Nobody knows why, and they aren't telling.