Cereal Mash
By Mark Tumarkin

Perhaps more information than you need to know....

For those of you interested in brewing a CAP, or other styles of beer requiring a cereal mash, here are some recent HBD posts on the subject (two from Jeff Renner and one from Marc Sedam), and a counterpoint opinion from Alan McKay.

<editor's note>
The following is taken from the Homebrew Digest.
</editor's note>

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From: Jeff Renner 
Subject: Re: Cornmeal

"John Misrahi"  wrote:

>If I want to use corn meal in a mash , in place of brewers' flaked corn, do
>I need to cook it first?

Yes.  The starches of corn and rice do not gelatinize and become 
available to the amylase at mash temperatures the way raw barley, 
wheat and rye do.

To cook, add about 30% malt ("premalt) (that's 30% of its weight, not 
30% of the malt in the recipe), mash for 20-30 minutes at 153F or so, 
then bring to a boil and cook for about 30 minutes for cornmeal or 
broken rice, longer for grits or polenta.  Then add to your main 
mash, which you have already mashed in at a proper temperature to 
accommodate the heat of the cereal mash for the next step.

Be sure to use plenty of water for the cereal mash, and adjust the 
minerals as you would for the main mash.  This means low alkalinity 
for a pilsner.  1.5 quarts per pound is not too much.  I mash in an 8 
qt. pot in a preheated oven at mash temperature, then bring to a boil 
and cook on the electric stove with a trivet or heat diffuser between 
the element and the pot.  This helps prevent scorching, but you still 
need to stiff frequently until you establish a boil and can turn the 
heat down to a simmer.

I just brewed a CAP yesterday for our daughter's wedding in August. 
It was 95F outside and hotter in my garage with the burners going.  I 
used the mash schedule I have settled on - mash in at 145F, rest for 
30-45 minutes while boiling the cereal mash, add the cereal mash, 
which brings the combined mash to about 160F (you may need to add so 
boiling water or heat), and rest another 30-45 minutes.  This 
produces a wort with high fermentability for a crisp pilsner.

Be sure to use degermed cornmeal, not whole corn meal, which has the 
oily germ present.

Jeff
- -- 
Jeff Renner in Ann Arbor, Michigan USA, JeffRenner@comcast.net
"One never knows, do one?"  Fats Waller, American Musician, 1904-1943



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Date: Thu, 04 Jul 2002 16:39:55 -0400
From: Jeff Renner 
Subject: cereal mash

Brewers

An HBD reader found that I didn't make cereal mash instructions clear 
enough, and after my answers, felt that they were good enough that he 
suggested that I post to the general readership.  Here it is:

>Jeff - I did not understand the meaning of the following in your 
>recent HBD post.
>
>>To cook, add about 30% malt ("premalt) (that's 30% of its weight, not
>>30% of the malt in the recipe)
>
>Would you please explain?

Ah, yes.  This seems to often cause confusion.  Here's the deal.  For 
my basic 8 gallon recipe, I use 11 lbs. of 6-row malt and 3 lbs. of 
cornmeal.  So, for the 3 lbs of corn meal, I use 30% malt, or 15 
ounces, with the corn.  Actually, I use a pound, but that's the idea. 
The premalt helps keep the cornmeal from turning into a lump of 
cornmeal mush.  I mash it at ~153F, then boil for 30-40 minutes, then 
add it to the main mash.

If this still isn't clear, fire away again.
- -------
>Jeff - Thanks for the speedy reply.  I think I have it now: you add 
>to the cornmeal an amount of malt equal to roughly 30 % of the 
>weight of the cornmeal, and then mash the mixture before boiling it 
>to gelatinize the cornmeal.  But what is the purpose of mashing 
>before cooking?  Boiling will destroy the enzymes in the malt mixed 
>with the cornmeal, but surely there are plenty in the main mash to 
>do the job.  So I would not expect the small mash to be the only way 
>to convert those starches.  But perhaps there is some benefit to 
>holding the cornmeal at 153 degrees for a while?
>
>      I have followed with interest the posts relating to CAP, and I 
>look forward to doing one before the summer is over.  But for right 
>now, the next HBD gleaning to be put to good use will be beer can 
>chicken on the fourth.  The grill is ready, the fixings are on hand, 
>and I'm hot to trot.
>
>      Happy Fourth!


You've got the idea.  This pre-mashing isn't to convert the starch in 
the cornmeal for the yeast, it's for ease of handling the cereal 
mash.  For the most part, the starch isn't gelatinized - that's the 
purpose of boiling.  Most of the it is converted in the main mash by 
the balance of the malt.

But there is some available starch in the cornmeal from starch bodies 
that were damaged by the milling process, and this starch can make 
the whole thing set up like stiff porridge.  Mashing this before 
boiling keeps it liquid.  I've tried the process both with and 
without the premalt, and the difference is remarkable.  This is more 
important in commercial scale brewing where the cereal mash has to be 
pumped.  I suspect there is also some breakdown of protein in the 
premash, but I don't know.  When this process was developed in the 
1870s or 80s, it made a big difference in the handling of corn and 
rice in beer and in the quality of the final beer.

Glad you are planning to brew a CAP - I have one fermenting now for 
my daughter's wedding in August.  I also have a Vienna mild (George 
Fix's recipe with changes for modern malt) lagering, and will brew 
ginger wit and a mild porter.

Have a great Fourth.

Jeff

- -- 
Jeff Renner in Ann Arbor, Michigan USA, JeffRenner@comcast.net
"One never knows, do one?"  Fats Waller, American Musician, 1904-1943



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Date: Fri, 05 Jul 2002 09:48:40 -0400
From: Marc Sedam 
Subject: cereal mash

Time for my bi-annual description of starch gelatinization,
and why it's important to brewing.  Jeff writes..

***You've got the idea.  This pre-mashing isn't to convert
the starch in
the cornmeal for the yeast, it's for ease of handling the
cereal
mash.  For the most part, the starch isn't gelatinized -
that's the
purpose of boiling.  Most of the it is converted in the main
mash by
the balance of the malt.

But there is some available starch in the cornmeal from
starch bodies
that were damaged by the milling process, and this starch
can make
the whole thing set up like stiff porridge.  Mashing this
before
boiling keeps it liquid.  I've tried the process both with
and
without the premalt, and the difference is remarkable.  This
is more
important in commercial scale brewing where the cereal mash
has to be
pumped.  I suspect there is also some breakdown of protein
in the
premash, but I don't know.  When this process was developed
in the
1870s or 80s, it made a big difference in the handling of
corn and
rice in beer and in the quality of the final beer.***


All starches created in cereal grains are contained in
microscopic packets called "starch granules."  Think of a
starch granule as a tightly packed collection of long starch
molecules balled up.  In order to access the starch inside
the granule, you have to provide three things:  heat, water,
and shear (stirring).  Providing a combination of these
three things will rupture/burst the starch granule and allow
the starch molecules inside to be available for whatever you
have in store for them.  An analogy would be a water
balloon, where the starch is the water.  The balloon
(granule) explodes and the water (starch) goes everywhere.
Same same.

Different starches have different "gelatinization
temperatures."  Back in the day, I used to have all of these
different temps in my head.  Now I can only remember that
corn is in the mid-70s (Celsius), wheat is in the 50s (why
you don't need to do a cereal mash with wheat, even if it's
unmalted), and rice is in the 70-80s.  Barley starches are
already broken down during the malting process and are
available without having to do a cereal mash.  Unmalted
barley should be treated just like any other adjunct.  Do a
cereal mash unless it's in the flaked, rolled, or puffed
form.

OK.  So why do you care?  This all becomes important in the
cereal mash.  Assume that we're going to make a delicious
Classic American Pilsner (CAP).

I use yellow corn grits as I live in the South and they are
very readily available.  But the explanation will hold true
if you use polenta or even corn flour (if you had to).   Add
your grits to the cold water (I use a 1:5 ratio) and start
heating.  As you heat the grits/water mixture it will start
to thicken.  This is because the starch granules are
starting to swell up as they take on water.  The mixture
will get thicker and thicker.  If you do not stir the grits
mixture it will turn into some kind of corn cement and burn
like mad.  This would be bad.  Again, without shear
(stirring) the granules won't break.  So at some point with
regular stirring (usually around 70C) the mixture will all
the sudden get thinner.  This is the point when the starch
granules have started to break down.  They release the water
they took up and the starches, reducing the thickness
(viscosity) of the mixture.  After this happens, the mixture
will stay a reasonable thickness UNTIL you remove it from
the heat.

Once you remove the mix from heat, the starch molecules will
automatically start to "retrograde," or curl up on
themselves.  Starch is a long-chain polysaccharide, meaning
that it's made up of hundreds of sugar molecules connected
to each other.  When starch in solution starts to cool, the
long chains start to crystallize (last I knew they actually
formed helices).  They bind water and the mixture will be
akin to a corn brick.  An interesting side note is that some
of the starch will crystallize so well that it is no longer
available for fermentation or digestion.

OK...back to brewing.

The addition of some barley malt significantly changes the
dynamic in the cereal mash.  The barley malt has alpha- and
beta-amylases which are used to break down starches into
simple, fermentable sugars.  So a few unique things happen
in the corn/barley/water mixture, which are very beneficial
to brewing with cereal grains.

1)  There are proteases and some lipases in the barley malt
which will help break down fats and proteins in the corn
grits.  But this is pretty insignificant.
2)  As the grits are heated and the granules swell, they do
leach out some starch molecules.  The barley enzymes will
break down these starches as soon as they escape the
granule. This keeps the viscosity (thickness) down.
3)  The swollen granule is also susceptible to being
degraded via amylases.  So many of the granules are being
broken down before they have a chance to burst.  This
further decreases the viscosity of the mixture.
4)  Finally, when the starch granules start to break *en
masse*, the amylases are there to break them down into the
fermentable sugars.  Combined with #s 2 and 3, the overall
result is a very manageable cereal mash in terms of
thickness.
5)  Whatever starch granules the barley malt cannot degrade
before the heat denatures its enzymes is burst during the
long boiling of the cereal mash.
6)  Since the starches are well broken down they do not
retrograde when you add the boiling cereal mash back to the
much cooler main mash.  Had the starches not been broken
down, you would get tiny clumps of unfermentable corn starch
in the mash.  In one CAP I brewed, I didn't boil the cereals
long enough and wound up with lots of these clumps, as well
as a lot of starch haze in the ferment.


So I've taken several hundred words to come to this
conclusion:  Do what Jeff says.  It works great.

Cheers!
Marc

- --

Marc Sedam
Chapel Hill, NC
"From the land of the free, yet home of a 6%abv limit on
beer."

             
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Date: Sun,  7 Jul 2002 11:15:27 -0400
From: Alan McKay 
Subject: premashing cereal grains

Marc Sedam writes an extremely detailed account of what happens
in the mash with cereal grains.  However detailed the account, 
I have to disagree with claim that pre-mashing is a requirement :

> This is more important in commercial scale brewing where the 
> cereal mash has to be pumped

Several years ago when I asked a brewmaster at Molson about this,
he said the only reason he could think of for pre-mashing was
the above, and he noted that I would understand the importance
if I'd ever had to shovel several tonnes of retrograded corn
or rice out of a vessel.  On a homebrew level even if the cereal
does retrograde, it will be far from unmanagable even in
a 15 gallon batch size.

> Had the starches not been broken
> down, you would get tiny clumps of unfermentable corn starch
> in the mash.  

Maybe if you didn't stir the mash properly or something.  I have
never premashed my starches and have used a great deal of rice,
various types of corn including starch, grits and flakes, and
even potato.  I have never once had an unmanagable, retrograded
mash, never had clumps of unfermentable starch, and never had
starch haze problems in the fermenting beer.

Some day maybe I'll try this pre-mash thing just for the sake
of comparison, but so far I haven't really found a reason to
try other than sheer curiousity.  Of course the question presents
itself "why wouldn't you?", given that the procedure is identical
either way.  If I were doing this for the first time I probably
would do it this way.  But I'm a man of habit.

cheers,
 -Alan


- -- 
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