You need to know
- what you want, and
- what ingredients or processes that will provide that.
What you want
When a beer is judged by an experienced judge, he'll start by classifying according to
aroma,
appearance,
flavor,
mouthfeel, and overall
drinkability. When you decide you want to make a beer, you will need to address each one of these. Each one can be manipulated by an ingredient or a brewing process.
Ingredients
Every malt has a different flavor, and might also contribute to other parts of the beer such as mouthfeel and appearance. I like what John Palmer said in his book How To Brew (he said it better in the book, but this is copied from the web):
To help get your creative juices flowing, here is a rough approximation of the recipes for the common ale styles:
Pale Ale - base malt plus a half pound of caramel malt,
Amber Ale - pale ale plus a half pound of dark caramel malt,
Brown Ale - pale ale plus a half pound of chocolate malt
Porter - amber ale plus a half pound of chocolate malt,
Stout - porter plus a half pound of roast barley.
Besides malt, yeast and hops can have a profound affect on your beer. Also, certain beers like soft Bohemian Pilseners can benefit from additives to the water as well.
Color is changed by the malts. Using software makes dialing-in the color very easy.
Process
The last part of your recipe must include process decisions like mash temperature, boil duration, fermentation temps, finings / chilling for clarity, etc. Another process decision, the hop schedule, affects the hop bitterness, flavor, and aroma of the beer, which of course has a great effect on the final product.
