Water comprises 95 percent of beer so the quality profoundly affects the taste. Tap water contains chemicals and other constituents that make it unsuitable for brewing. Removing chlorine is simple. Since it is in a gaseous state, it will readily outgas if let set over night or if it is boiled. Some water treatments facilities use chloramines to disinfect water. This is a bit more difficult to remove. Typically active carbon filters can be used to remove chloramines. Sodium or potassium metabisulfite treatments will drive off chloramines as well. Alternatively, purified water may be purchased for brewing. Minerals dissolved in the water affect the taste significantly. They can interact and alter the flavors of hops and malt. Brewers can adjust the ion levels to produce the flavor they most desire.
Yeast is available in both liquid and dry forms. Always use fresh yeast. There are a number of strains to choose from depending on the characteristics desired of the beer. The type of sugars used in a beer can affect the fermentability and flavor. Some brewers use refined sugars while others prefer those that are less refined. Each reacts differently to impart distinctiveness in aroma, alcohol content and taste. Experimenting with different types of sugars will allow the brewer to determine their preference.