Irish Moss

I plan on brewing a Honey Kolsch and a Caribou Slobber today. I picked up some Irish Moss to aid in the clarity of the beers.

Directions are simple, add 1 tspn to the last 15 minutes of boil for a 5 gallon batch.

What happens to it once you go from kettle to fermentor? I usually pour the beer from the kettle to the bucket through a strainer.

Why wouldn’t the moss filter out during this time?

Is the main advantage from using the Moss obtained through the boil, making the physical moss not needed during the fermentation?

I usually use the 2-stage from the few batches I have made to date. However, I am beginning to be convinced it isn’t necessary. I was going to do both the above mentioned beers w/o using a secondary stage and go with the Irish Moss.

Thoughts on either the Irish moss and/or not using a secondary for either of the above beers?


Irish moss is for the boil, don’t worry about it not getting in the fermentor.

I only boil 2.5 gallons. Should I use only 1/2 tspn for 2.5 vs. the 1 for 5?

The remaining 2.5 gallons is added later to assist in cooling the wort and topping off to 5 gallons. I know this is probably thinking too much into it, but I’m still curious.

Probably, I have always done the 1 tsp for my partial boils, partial mash and BIAB. But I probably should have been scaling it for the boil size. That being said I have never noticed an earth/moss flavor at all.

I did learn on this board to rehydrate the moss with enough water to just cover the moss in a dish before adding it.

Yep don’t over think it. Absolutely hydrate it. If you’re committed to the hobby start investing toward full wort boils. Huge improvement.

Can’t wait til that point of this hobby.
We have 4 batches down and having a larger kettle would be great. But, the costs can get up there. Here’s my order of importance:

  1. 5 gallons soda kegs x 4
  2. kegerator (1950s style)
  3. chest freezer (maybe two of these)

After those, then I can worry about the kettle sizes and an outside burner.

As for the moss, we definately hydrated both batches yesterday. I didn’t make a big fuss about the amount used though. I figure it is so little spread out over the full 5 gallons of beer at the end…who cares.

You should be able to get a burner and 10G pot for less than 2 kegs.

I take a little bit of wort at the beginning of the boil, put it in a coffee cup with the IM, and by the tail end of the boil it is well hydrated and ready to rock.

I would get the chest freezer and temp controller FIRST (before kegging or even AG/full boil equipment). Dialing in ferment temps will change what you make from ‘homebrew’ to ‘beer’.

Kegging stuff is very expensive. 10G stainless steel pot, buy a weldless valve fitting, step drill it in, and you could get into AG/full volume boil for well under $100 (check out

Personally I think full wort boil trumps temp control. While I agree that temp control is important I think most guys should be able to find a space that will work for fermenting. If you are not lucky enough, find a fridge on craigslist.

I hate to admit since I am a less is more kinda guy but whirlfloc really does outperform IM.

Man, I’d rather have 1 keg of good brew than 4 lame partial boils on tap.

A recommendation for a burner:

Zwiller, I’m of the exact oposite opinion from you. A full boil is most important in improving color (hard to get really light beers without it), but the impact on flavor is pretty small. Temperature control can make the difference between good and great beer; you are directly controlling ester production from the yeast.

That’s cool.

With my water (which is actually pretty good) I bet if I measured the resulting wort pH of a partial boil it would be much higher than it should be, giving it a flat taste. Very much a “homebrewed” taste. It will get you drunk though…

Like I said, temp control is important but I find that most yeast strains are fairly forgiving provided you don’t far exceed max temps. Maybe I am fortunate that my basement remains nice and cool all year long. Sure, lagers are another story…

A cool basement can be just as good as a fridge with a controller. I used to live in a 150 year old house with a fieldstone foundation that was dug into the side of a hill. Between that and the variable insulation that got added over the years, I could always find some spot that was perfect for any stage of ale production, and in the depth of winter, could even handle lagers. But now that I live in a modern house without a basement, I need that controller to keep the beers clean-tasting.