What are the main ingredients in beer?

This question was asked by an individual looking to brew beer at home. Even though it is geared towards brewing, it is still a good description of the main ingredients of beer.

In its most simple form, beer is made of four basic ingredients: Water, yeast, malt, and hops.


As is the case with the human body, the most abundant ingredient in beer is water. Over 95% of your brew is made up of water. With such a large amount of your final product coming from a single ingredient, you can imagine how important it is to use good water.

When brewing at home, it’s best to use filtered, or better yet bottled water from the store (make sure that your bottled water is not just tap water in a bottle). This is much easier than testing your tap water, finding out what the mineral and chemical make up of it is and then using additives to get the balance just right (this is a technique used by more advance brewers to try and match the exact water make up for certain beers. An important point to mention here is to NOT use “distilled” water as your main source for brewing – the distilling process removes many of the natural elements that are beneficial to beer making.


Yeast is the engine that makes the whole process go (without yeast, you would just have a sweet, brown, tea-like substance with no alcohol… I shudder at the thought). Yeasts, part of the fungus family, are single-celled living organisms that eat sugars and convert them into alcohol and carbon dioxide through the wonderful and amazing process called fermentation.

In order to make a great beer you can’t just use any old yeast that happens to fly by (the fact is that yeasts are everywhere… hey there’s one right there.. watch out!). Wild yeasts can all but ruin your beer if they get in during the brewing process (unless, of course, you are making a true Belgium Lambic). The yeast we want is usually classified as “Beer Yeast” – yeasts that are specifically cultured for the purpose of brewing beer. There are two main types of beer yeast, lager yeast and ale yeast, and both are discussed further in Ales v. Lagers.

Malt – Traditionally malted barley

Malted barley is really nothing more than barley grains that have been soaked in water until they first begin to sprout. When the barley begins to sprout it draws on its starch reserves, which are transformed into simple sugars. This is the food we will be feeding to the yeast later. The barley is then dried and cured, creating a perfect source of sugar and soluble starches for the fermentation.

When it comes time to brew, the malted barley needs to be cracked and boiled in water in the process known as “mashing”.

As a side note, it is important to mention that not all beers use barley; it is just the most common grain used. Many styles and brewmasters will use wheat, oats, rye, or other grains (called adjuncts) in the brewing process. While many of the beers brewed with adjuncts are good quality beers that simply use the alternative grains to create new flavors or styles, many of the larger breweries, especially in the US, will use rice, corn, or other inexpensive grains to simply save on costs. The corn and rice are used primarily as cheaper sources of fermentable sugar. These larger breweries use these “add junks” (I mean adjuncts), sometimes as high as 40% of the grains used, to produce more beer at a lower cost. You can definitely taste the difference (and I don’t mean in a good way).


Hops, a distant cousin to cannabis, are the “conelike” flowers that come from this vining plant. There are over 50 different recognized varieties of hops with names like Saaz and East Kent Goldings. Hops are used in beer much the same way spices are used in cooking – to enhance the flavor and smell of the final product.

During fermentation, not all of the sugars from the malt will be consumed – leaving the beer with a sweet smell and flavor. Hops, which adds a certain degree of bitterness, a spicy flavoring, and a distinctive aroma, are especially useful in balancing this sweetness. However, this is not the only reasons that hops are used in brewing beer. Hops are also known to act as a bacterial inhibitor and as a natural clarifying agent.

Other Ingredients

Beyond the four basic ingredients of beer mentioned above, there are a number of other flavorings and additives that can be added to beers to create different styles, flavors, and characters. While we suggest using a Beer Kit while starting out, the addition of these “extra” ingredients is not very difficult and adds to the interest and complexity that any good hobby must have to keep you interested over time. Many of these adjuncts are explored in the more Advanced Brewing processes.