« on: February 15, 2012, 07:28:11 PM »
It's about yeast, proteins, tannins/phenols, and starch. Start with a mash suited to the malts and with a complete conversion. Sparge at the right pH and temp. Get good hot and cold breaks in the kettle. Kettle finings can help with the cold break. Break just means making proteins insoluble. Some more proteins will broken from solution after beer is cooled as chill haze and will slowly fall to the bottom. They will hit the bottom faster in a shallow container (like a bottle.) Gelatin or isinglass have a ionic charge that binds to yeast and some proteins adding mass so they will fall faster to the bottom. Polyclar has the opposite charge and can get other proteins and tannins. As long as you don't have starch in time all beers will clear. Fining or filtering just speeds up the process.
Extract brewers have a lot less of these problems to worry about. The extract manufacturer took care of most of them. Most steeping grains do have some starch though.