Amount

• Not all brewers agree as to exactly how much Irish moss to add to a beer. Brewing guru Charlie Papazian suggests using 1/4 teaspoon, but some recipes call for as much as a full teaspoon. The Irish moss does not add any flavor to the beer, so using a little more or a little less will not negatively impact your brew.
  
  

Procedure

• Irish moss should be added to the wort, the sugary concoction that becomes beer through the process of fermentation, during the last 15 minutes of the boiling stage. Certain types of flavoring hops may be added at the same time depending on the beer recipe you are using. The wort can then be strained (a sanitized colander will work for this) into the fermenting bucket to help clear your beer even more. This will eliminate larger particles from the wort, but still allow some of the Irish moss into the fermentation bucket to continue clearing the beer.
  
  

How It Works

• Irish moss is a fining agent. Over the course of the fermentation process, Irish moss gathers the smaller protein, polyphenol and lipid particles together and thereby forms larger particles that will settle easier at the bottom of the fermentation bucket. These molecules, if left to their own devices, will form a cloudy haze in your beer.
  
  

Irish Moss

• Irish moss is not technically a moss. In reality, it is a form of seaweed that grows along the Atlantic coast of North America and Europe. Most of the commercially used Irish moss comes from the coast of Ireland, Brittany and Massachusetts. In addition to being used as a fining agent, it is also used in the preparation of certain foods and in treating ulcers, stomach acid and chronic cough. For brewing purposes, Irish moss can be bought a brewing supply stores.