What are the pros and cons of using irish moss versus whirlfloc tablets for clarifying beer?
I used Irish moss for many years before switching to whirlfloc. But I think that was an availability thing more than anything else.
In my experience whirlfloc is easier to use, with few draw backs. But in real world application the two are practically the same performance wise.
In my experience, Whirlfloc works better. I used Irish moss for my first couple of years, until I found Whirlfloc. The first time I tried it I was amazed at how clear my wort got. I chill by putting my kettle in a tub of cold water, and the visual effects of a Whirlfloc-treated wort when it hits about 25 degrees C are pretty cool. I've never seen anything like it in my Irish Moss batches.
Yesterday I did my first batch going back to Irish Moss (I ran out of Whirlfloc) and it did not clear nearly as well as all my Whirlfloc batches.
Maybe I'm not using enough Irish Moss. I'm using about 1 tsp in 5 gallons, re-hydrating it in warm water before putting it in for the last 10 minutes of the boil. I think I'll try a couple more batches with IM, but if I don't get better results I'm going back to Whirfloc.
I should clarify that I'm talking about pre-fermentation clarity. I get crystal-clear wort when using Whirlfloc, but I don't think I've ever seen that with Irish Moss. But I'm not sure about the difference between the two post-fermentation. I always have significant chill haze with both, and I haven't really compared the two. But I've found that pre-fermentation the difference is striking.