Irish moss substitutions?
I have read about using Irish moss in brewing to clarify beer but I have not tried it yet. I am curious, however, as to whether or not I could use other sea vegetables in the same way or as a nutrient boost in my homebrews. Would there be any advantage or disadvantage to adding kelp/kombu or alaria/wakame (or any of the other number of seaweeds) to the wort? Would it matter when I added it?
David Bigelbach
Shirley, Massachusetts

Irish moss is the general name given to the red algae Chondrus crispus that grows in the Atlantic ocean off the shores of Europe and North America. The reason that Irish moss works as a fining agent is that it has a high density of negative charges on its surface and when added to wort it binds with certain proteins that have positive surface charges. Like many things added to beer I often wondered when some brewer decided to add this “seaweed” to the kettle . . . it probably was the same brewer who added fish swim bladders to beer!
   
The nice thing about Irish moss is that it works and it is pretty cheap. I have never heard of adding kelp or wakame to wort for similar purposes. I suppose they may contain similar charged polysaccharides and may also act as fining agents. The only way to know is to give these other seaweeds a try. But I don’t see much advantage since the use of kettle finings is pretty simple and these other seaweeds most likely will perform no better than Irish moss and may not work as well.