Beer is the world’s most widely consumed and probably the oldest alcoholic beverage. All you need is malt extract (grains), hops, yeast… and pure water.
Malted barley is soaked in hot water to release the malt sugars. The malt sugar solution is boiled with Hops for seasoning. The solution is cooled and yeast is added to begin fermentation. The yeast ferments the sugars, releasing CO2 and ethyl alcohol. When the main fermentation is complete, the beer is bottled with a little bit of added sugar to provide the carbonation.
As any experienced brewer will tell you, 80% of the secret of success is cleanliness. Thoroughly clean and sanitize everything that is going to come in contact with your beer. The easiest way to do that is to use an electric dishwasher set at the high heat setting or use a powdered cleanser such as PBW (Powdered Brewery Wash).
Rinse off bleach before using items using very clean potable or distilled water. Do not assume tap water is sanitized for rinsing brewing equipment.
If you’re using bleach to sanitize, add one ounce (30ml) of bleach to five gallons (19 liters) of cold water, followed by one ounce (30ml) of white vinegar. Do not mix the bleach and vinegar together before adding to the water! The vinegar will make the water more acidic, which helps the bleach sanitize.
Do not rinse iodine solutions, let equipment drip dry instead. Note that bleach can cause unwanted flavours in your beer, and requires rinsing, which can introduce microorganisms to your sterilized equipment. If you want to sterilize your equipment properly, use either a food-grade cleanser or sanitizer such as One Step No-Rinse Sanitizer, which requires no rinsing; or an iodine solution such as BTF Iodophor. Remember, in beer brewing, you can do just about anything you want, and add anything you want, to make whatever kind of beer you want—but proper sanitizing is the MOST important thing you can do. Take the time and the energy to do it right.
Prepare everything before you begin. That includes cleaning and sanitizing as outlined, and also includes having all your ingredients prepared and measured in advance. More about the brewing process on wikihow.com