etI've not experiemented with this myself (too lazy!), but according to Korzonas' "Homebrewing", home experiments that he ran indicated that rehydrating irish moss by soaking in a bit of clean water for 12-24 hours prior to dropping into the last 15 min of a boil did indeed result in better clarification. Adding dry is, clearly (get it?), better than adding no moss at all, but since it's no extra work to rehydrate why not?
Also, Korzonas writes that adding too much moss (more than a seemingly paltry "1/4 teaspoon of refined Irish Moss flakes for a 5 gallon batch") actually results in MORE chill haze. Less than if no moss was used, but more than if the correct amount were used.
Al Korzonas in Homebrewing Vol. I did a few experiments with Irish moss. While I don't have it handy, it seems he experimented with re-hydration, and concluded that while re-hydrating 24 hours in advance in optimum, 1 hour works nearly as well. It also seems that he concluded that it should be pitched 15-20 min before the end of the boil, and that 1 tsp per 5 gallons was optimum - anything above 2 tsp and you get into the flavor threshold for extremely light beers like American Lite, kolsch, helles, etc.
From: Al Korzonas <korz@xnet.com>
Subject: Irish Moss
Date: 1998-02-26 19:39:37 GMT
Andy writes:
>The correct amount of irish moss to add is highly dependent on many
>factors. Most homebrew texts recommend far less than is ideal (1/2
>teaspoon per batch instead of ~1 tablespoon), so in many cases it won't
>do much at all. Using even 30% less than the optimum can result in poor
>cold break flocculation.
I wish I had my copy of Dr. Fix's new book here... I'm pretty sure this
would be in there, but he was good enough to send me a copy of a paper
he had written a few years ago which described some experiments he ran
with Irish Moss. Several different varieties of IM were tried at several
different concentrations. Rehydration of the IM was done and it was
stressed that this was very important. There were tradeoffs between
head retention and clarity and a few other factors, but my reading of
the data indicated to me that 1/8 gram per liter of *refined flakes* was
the best choice. After determining this, I immediately called L.D.Carlson
(my primary wholesaler at the time, when I owned a HB shop) and asked
what kind of IM they were shipping me. It turns out it was "refined
Irish Moss flakes."
Note also that in one of the Beer and Brewing books (the transcripts of
the AHA National Conference) there is a talk by Terry Foster on finings.
He explained why "too much" of a fining is worse than "not enough." My
own experiments have shown this to be true.
I weighed out 2.4 grams of those L.D.Carlson refined flakes and found that
it was pretty close to a level TEAspoon.
Now, let's think about how extract is made for a second. It is concentrated
from a normal wort, right? I had a suspicion that the amount of IM you
need is dependent on the amount of protein in the wort and if some of
the protein was removed as break from the extract during production, extract
batches would require less IM, right? My experiments indeed confirmed
this suspicion.
To make a short story long, my tests indicated that, for a 1.050 OG
extract wort, 1/4 TEAspoon of rehydrated, refined Irish Moss flakes was
the proper amount. This happens to be exactly the amount that Charlie
Papazian recommends in his book, but I don't recall if he distinguishes
between extract and all-grain amounts. Note that this should scale
linearly... for a 1.100 extract wort, 1/2 teaspoon should be correct.
It could be that higher amounts of IM are needed when rehydration is
not done or in high-protein worts or on worts whose pH is radically
different than the norm... that might explain why some people find they
need a lot more than these recommended amounts
I had better shut up now... you've heard the story about free milk and
a cow right?
Al.
Al Korzonas, Palos Hills, IL
korz@xnet.com
My new website (still under construction, but up-and-running):
http://www.brewinfo.com/brewinfo/
)
C'est probale, l'influence de la quantité sur la tenue de mousse doit rester valable (mais ce n'est pas vraiment le sujet)brasseriefernande a écrit :Tout comme P-M j'utilise l'IM sous forme de pastille. J'imagine que la réhydratation concerne uniquement les algues restées sous forme naturelle.
Alors je suis dans les clous, parfait !brasseriefernande a écrit :EDIT: Concernant les citations d'oeuvre, elles sont autorisées sous certaines conditions. Le nom de l'auteur et la source doivent être clairement ciundiqué, la citation doit être partielle (juste ce qu'il faut pour appuyé ton idée), et l'oeuvre cité doit être publiée.
Tu fais une garde à froid ? J'ai constaté une nette différence entre mes premiers brassins où je n'utilisais pas l'IM et les suivants (et aussi ceux où j'ai oublié).chente a écrit :je ne connaissais pas cette réhydratation.
Je mettais 5 gr pour 20l, 10 min avant la fin d'ébu. Mais un jour funeste, le sachet s'est tari...et je n'en avait plus..
Mais je n'ai pas constaté que sans irish moss, ma bière était moins limpide. et je n'ai plus utilisé ce produit.
mais peut être que le dosage n'était pas correct, ou la procédure...
J'avais lu des trucs variés sur les quantités et sur le moment de l'ajout sans avoir eu une réelle démonstration, du coup je greffais ça à un ajout de houblon, tantôt à 10, 15, ou 20 min selon la recette… Maintenant ce sera réhydraté, ajouté à 15min, pas plus de 2g et on verra ce que ça donneGobelin Brassicole a écrit :Par contre, c'est intéressant ces 15mn... Personnellement, j'avais quasiment toujours lu 10mn et c'est ce que j'ai toujours fait...
