Most beers use only four main ingredients. There is no limit, however, to one's imagination by incorporating herbs, spices, fruits, or other plants or vegetables. Primarily though there is plenty of room for creativity, flavor, and aromas by using the 4 pillars which are:
Barley represents the grain, which is rich in fermentable sugars. These sugars give the sweet taste, as well as provide the nutrients for the yeast to produce alcohol. These fermentable sugars are found in other grains including wheat and rye strains, both of which are common for producing beers. Other forms of sugars are found in ingredients known as adjuncts and include rice, corn, and many less known varieties found in other regions.
Hops is a bittering agent for the brew and contains oils and resins that provide both flavor and aroma. Hops has become standard for brewing, although this was not always the case. Moreover, different types of 'beer' around the world use other herbs and spices in place as hops, all to create bitterness, act as a preservative, and create aroma.
Yeast is really the man behind the wheel for the beer making process. It is as important for the flavor and overall quality of the beer as any other ingredient. Its common for this ingredient to be under valued by a new brewer, since it does not come with the same flair as the other ingredients. You can feel the barley in your hands, smell the hops with intensity, yet the yeast comes in a small vial, or even in a powder packet. Regardless, keeping the same recipe, yet changing the yeast will yield wildly different beers.
Water of course is a given, but is as substantial as any other ingredient when it comes to its quality and taste. The beers of Belguim, made with the soft waters will differ from those made with the same recipe from any other part of the world.
Adjuncts, Sugars, and Other Ingredients
Aside from the four pillars, there are many other ingredients that can be added to beer, either in the brewing process, or during the fermentation process. Alternative grains and cereals can be used including wheat and rye. Cereal adjuncts are used to both supplement the fermentable sugars in the beer wort, as well as supply flavor and add to shelf life. These come in both liquid and dry form.
Ever had jalapeno beer? Peppers, pumpkin, fruit, and berries can all be added to modify the flavor and are common in seasonal ales. Not to mention the use of herbs and spices, such as coriander, cinnamon, and vanilla are just some of the ingredients possible for brewing beer