Equipment and Ingredients
The carboy is the vessel in which the beer is fermented. Most homebrewers use five gallon glass carboys, although some have graduated to stainless steel vats. Often carboys can be bought from water-delivery companies, although most have switched over to plastic bottles, which is not recommended for homebrewing. They can also be purchased from brewing supply shops. As with all other brewing equipment, make sure your carboy is sanitized before it touches any beer. There is an airlock atop this carboy to release gas.
The airlock is simply a one-way valve containing water which allows the release of carbon dioxide produced by the yeast during brewing but prevents entry of any oxygen, wild yeasts or bacteria. The vigorous fermentation of the beer would cause the carboy to explode without it!
The hydrometer is used to measure the specific gravity of beer. This in turn is used to calculate the alcohol content. The hydrometer is also used to approximate sugar content of unfermented beer.
A simple equation is used: Original Gravity-Ending Gravity x 105 x 1.26 = percent alcohol by volume
(thanks to leeners.com for this formula)
Hops are a flower used to flavor beer. They produce the pleasant bitterness found in varying degrees in beer. They are added a number of different times during the brewing process, according to recipe.
Malts are boiled in water to create the wort, which will be fermented to make beer. Often, both a malt extract from a can and whole-grain malt will be used together. Sugars in the malt will feed the yeast during fermentation.
Yeast are what cause the magic to happen in homebrewing. Brewer's yeast is either sold in dry packages or vials, as seen on the right. The yeast is added to the chilled wort after boiling and consumes sugars, producing alcohol and carbon dioxie before it goes dormant. Just before bottling, additional sugar is added to the yeast again to encourage it to produce more carbon dioxide, thus carbonating the beer.
Thanks to Gary, Lane and Leneers.com for their expertise