I really don't want to start a major battle over the use of Irish Moss in beer making, just wish to become more educated about the use of this product. I have reviewed the pro and con websites, that say, of course it's bad or it's safe. Is there any specific independent research or information online that isn't bias? I'm happy with my beer sans Irish Moss, so most will say I've made my choice already. Just looking for legitimate information to add to my knowledge base. Thanks for any insight.

  • Without being able to find credible sources of legitimate test information, Google'ing "Irish Moss" brings up far less controversial health articles than "Carrageenan". If the option were available, I'd go with Irish Moss off that alone.
    – Scott
    Feb 21, 2014 at 14:44
  • From wikipedia: "Chondrus crispus (Irish Moss) is an industrial source of carrageenan".
    – GHP
    Feb 21, 2014 at 14:50
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    This is a controversial issue, so I'd be wary of any advice you get on here or anywhere else, unless it cites studies, and even then I'd be wary. It's like asking if it's safe to use a plastic cooler as a mash tun. No one really knows if it's safe but tens of thousands of people do it. If you are worried about it, just leave it out. It's a purely aesthetic thing and there are other ways of clarifying beer.
    – paul
    Feb 21, 2014 at 21:54
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    Thanks for posing this question. In researching my answer, I've come to the conclusion that I'm better off leaving Irish moss out of my beers. There's a lot of scientific evidence pointing to a possible harmful effect, and I don't place much value on crystal clear beer. Feb 22, 2014 at 0:04
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    Thanks everyone for your direction, I have to agree with Paul & Tobias, nothing I've read concludes that IM is 100% safe in beer as a fining agent, and as stated, I'm not pleased with it's use in the food stream. Since I drink more beer then eat ice cream, I'll leave the IM out of the pot. ;-)
    – Quentin
    Feb 22, 2014 at 2:25

4 Answers 4


The Wikipedia article on carrageenan outlines a number of peer reviewed animal studies, the results of which are mixed with some researchers claiming carrageenan poses no health concerns, while others assert that it promotes gastrointestinal tract inflammation and increased incidence of tumours.

This study found no correlation between dietary carrageenan and tumour formation

  • Cohen S and Ito N (2002) "A critical review of the toxicological effects of carrageenan and processed eucheuma seaweed on the gastrointestinal tract." Crit Rev in Toxicol 32(5) 413-444

Studies that found an increase in tumour formation:

  • Watanabe, K., Reddy, B. S., Wong, C. Q., & Weisburger, J. H. (1978). "Effect of dietary undegraded carrageenan on colon carcinogenesis in F344 rats treated with azoxymethane or methylnitrosourea" Cancer Research 38(12), 4427-4430.

  • Taché, S, Peiffer, G, Millet, A-S, and Corpet, DE. "Carrageenan gel and aberrant crypt foci in the colon of conventional and human flora-associated rats." Nutr Cancer 37:75–80, 2000.

  • Corpet, DE, Taché, S, and Préclaire, M. "Carrageenan given as a jelly, does not initiate, but promotes the growth of aberrant crypt foci in the rat colon" Cancer Lett 114:53–55, 1997b.

These studies show a link between GI inflammation and dietary carrageenan:

  • Bhattacharyya S, Dudeja PK and Tobacman JK (2010) "Tumor necrosis factor alpha-induced inflammation is increased but apoptosis is inhibited by common food additive carrageenan." Journal of Biological Chemistry 285(50): 39511-22

  • Borthakur A, Bhattacharyya S, Anbazhagan AN, Kumar A, Dudeja PK and Tobacman JK (2012) "Prolongation of carrageenan-induced inflammation in human colonic epithelial cells by activation of an NFκB-BCL10 loop." Biochimica and Biophysica Acta 1822(8): 1300-7

  • You should include some of the citations from the article in here.
    – paul
    Feb 21, 2014 at 22:19

I am no scientist, but I would think that since Irish Moss is only used as a coagulant and precipitant in brewing that the amount retained in the beer after racking would be significantly less than say ice cream, where it is used as a gelling agent.

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    Even if there is a risk associated with it, the risk must be significantly lower when it's used as a fining agent than as a setting agent: we typically use maybe a teaspoon of irish moss in a 5 gallon brew length as a copper fining, and the majority of that will end up settling out in the trub (which is the aim of fining, after all), so very little indeed would be consumed in a glass of beer. A quick search suggests use as a setting agent requires around an ounce of carageenan per cup of liquid, all of which will be consumed.
    – Bryan
    Feb 21, 2014 at 16:58
  • Even if you were a scientist, you should at least link to some evidence for this, as the poster asks specifically for "specific independent research or information online".
    – paul
    Feb 21, 2014 at 22:18

Carageenan in processed meat, dairy or beer causes a splitting headache in me which begins 1 to 2 hours after consumption and continues if not treated for 18 hours. Therefore i drink only German beers which by law do not contain carageenan.


The difference is that you consume the carageenan in ice cream. It drops out in beer so you don't consume it.

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    I realize you have a high reputation are a well-known homebrewer, but how do you know this to be true? Unless you can show that it's been lab-tested, it's at least rational to think that if you add some carrageenan to your beer you might then consume that carrageenan later if you don't filter it out. I understand how it works and that in theory it settles out, but it seems possible that 100% does not settle out - i.e. some of it is consumed, and no one knows how safe it is, esp. for people with IBS or other GI issues.
    – paul
    Feb 21, 2014 at 22:17
  • Paul do you have any scientific evidence that it doesn't drop out? AFAIK, it's R'gebot compliant which would mean it doesn't remain in the beer. If I wasn't so busy I'd try to find citations for you. Maybe in a week or so I can do that.
    – Denny Conn
    Feb 21, 2014 at 22:52
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    No I don't, but that's why I didn't post an answer to myself. It's a hard question to answer with evidence and citations, and I don't have time to research it right now either unfortunately. But I have read this well-researched report - cornucopia.org/wp-content/uploads/2013/02/… - which makes it clear that carrageenan is a controversial ingredient that deserves a lot more attention and research than it has gotten considering that there is some evidence of ill effects even in small quantities and it's very widely used.
    – paul
    Feb 21, 2014 at 23:54

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