hist-brewing: Re: Crystal Malt and Torrified Wheat
JeffRenner at comcast.net
Sun May 26 13:55:35 PDT 2002
Mike Bennett <mjb at efn.org> wrote:
>Scotti <PBLoomis at aol.com> wrote:
> > The sugars crystallize out, and are thereafter much harder
> > for any amylase enzymes to break down. They remain complex,
> > and contribute both mouthfeel and sweetness to the resulting
> > beer.
>This statement is incorrect. The sugars produced are soluble and will
>be broken down by any amylase present from the base malts used. I
>believe that this misconception is brought on by homebrew texts that
>instruct the homebrewer to add crystal to their extract beers for more
>sweetness and mouthfeel. Since extracts don't have active amylase the
>large chain sugars present in the crystal malt won't be broken down.
This is a question that puzzled me, so I asked it four years ago on
HomeBrew Digest. Mort O'Sullivan, then a student at the
International Centre for Brewing and Distilling at Heriot-Watt
University in Edinburgh, Scotland, answered. He stated that the
sugars in crystal malt are indeed resistant to fermentation. This
has been my own experience, although I've never done an actual
Below is his original post and his reply to another question. This
is an incredible bit of information that I believe is accurate. I
hope it is of use to the readers of this list.
Date: Thu, 2 Jul 1998 22:12:04 +0100
From: "Mort O'Sullivan" <tarwater at brew-master.com>
Subject: RE: crystal malt: call for discussion
Jeff Renner calls for a discussion on crystal malt, primarily
questioning whether it is really true that the sugars from crystal
malt are less fermentable than those from standard malts.
>It seems to me that there is nothing inherent about this procedure
>should produce more unfermentables than a standard mash. If a
>regime is used in stewing that would result in higher unfermentables
>conventional mash, the result should be the same.
>Now it may be that the stewing is indeed done at such temperatures
>routinely, resulting in high unfermentables. I think that maltsters
>researched the results of temperature regimes, both regarding sugar
>profiles and protein profiles, and control these precisely. And, of
>course, the caramelization of most crystal malts' sugars adds an
>flavor component not easily (or at all?) achieved otherwise. Perhaps
>these caramelized sugars that are less fermentable than they would be
>uncaramelized? I don't think so, but I'm trying to think of all of
These are very good questions. The starting point for creating
crystal malt is usually well modified green malt at >43% moisture and
the initial air on temperature is usually 65-70*C. Holding at this
saccharification temperature is often compared to mashing within the
kernel, but some important differences should be kept in mind. First,
at about 43% moisture, the liquor:grist ratio is much lower than in a
normal mash; and second, the "grist" is never milled but simply
consists of starch-and-protein-containing endosperm cells whose walls
have been degraded during germination by endoproteases and beta
glucanases. These conditions limit the amylase enzymes' access to
substrate compared to normal mashing conditions. There are still
plenty of reducing sugars released to react with the primary amines
in Maillard reactions to form the reductones, furans, pyrroles,
pyrazines and countless intermediates that provide the characteristic
flavors and colors to crystal and caramel malts. Once caramelized,
these sugars are no longer sugars, and so are not fermentable by
However, only a small percentage of the sugars actually undergo
Maillard reactions and so presumably there are plenty of other
sugars, dextrins, and partially degraded starch molecules remaining
that would eventually contribute to fermentability, especially after
they are mashed in the presence of the "healthy" enzymes from the
normal malt that makes up the majority of your grist. But this is not
the case. Why?
Starch molecules in barley are approximately 25% amylose, and 75%
amylopectin. Due to the limited enzyme mobility described above, the
amylopectin is preferentially broken down because the complexity of
the molecules "entraps" enzymes in microchannels on the surface of
the amylopectin molecules. The much longer, straight-chain amylose
molecules are solubilized, but survive the process relatively
unscathed. During the later, high temperature stages of kilning and
subsequent cooling, these solubilized amylose molecules tend to
recrystallize in a process called retrogradation. For reasons not
entirely understood, these recrystallized amylose molecules are very
resistant to enzymic hydrolysis and so will not yield fermentable
It has also been noted by many researchers that regardless of the
type of malt being produced, there is an inverse relationship between
the time spent at high temperature in kilning and the fermentability
of a malt. As crystal and caramel malts can spend quite a long time
at temperatures as high as 150*C, it makes sense that their
fermentability may be severely reduced.
Hope this helps.
Date: Wed, 15 Jul 1998 22:30:30 +0100
From: "Mort O'Sullivan" <tarwater at brew-master.com>
Subject: Crystal Malt Questions
I was afraid someone might ask for clarification regarding my earlier
post. Thanks, Steve.
Starch retrogradation is a pretty complex physical phenomenon and
could be better explained by a rheologist than a brewer. But I'll try
to tell you what I know and show you where I found the information.
>In capsule form it says:
>malt is 25% amylose and 75% amylopectin (this checks out)
>stewing of crystal malt favors amylopectin-lysis [- hmm why ? all enzymes
>are just as short of water. - Isn't BA smaller to start with ?]]
Even in a normal mash, amylopectin is broken down faster than
amylose, which is explained by the fact that the complex structure of
amylopectin molecules tends to entrap amylase enzymes. In conditions
such as stewing crystal malt, free movement of enzymes would be even
more restricted and the time of stewing at 65*C is generally shorter
than the time for a full mash, so a lot of amylose would be left
>only a small % of the sugars undergo Maillard reactions and become
>unfermentable by this mechanism during kilning, the relatively
>unchanged amylose molecule recrystallize [or perhaps crystallize is
>better - since it's the first fime - No Mort?]
No, I think 'recrystallize' is better since the starch granules are
already in a crystal structure before gelatinization. The conditions
for the retrogradation of starch require that the starch molecules be
gelatinized and then that they be cooled to below the gelatinization
temperature before they are fully hydrolysed. The slower the cooling
and the longer time spent at the low temperatures, the more
retrogradation occurs. Retrogradation is also promoted by relatively
long chain lengths (>100) and association with lipid molecules, so
amylose molcules retrograde faster than amylopectin molcules.
Retrogradation of starch is one of the primary mechanisms of bread
staling and most research has been focused on that area rather than
brewing. One interesting thing I read about wheat starch is that
while in its natural state it gelatinizes at ~55*C, after
retrogradation its gelatinization temperature is 105*C. Whether this
is the case with barley starch I am not sure, but it could explain
why it is resistent to enzymes.
>and by an inexplicable mechanism become unfermentable - that is -
>insucceptable to amylase enzymes.
>regardless of malt type - high temp kilnoing => lower fermentability.
The amount of time spent at the high temperature is as important, if
not more important.
For those interested in reading more about this stuff, I got most of
the information from these sources:
(1) Gretenhart, K.E. "Specialty Malts." _MBAA Technical Qtly_ 1997 v.34 n.2
(2) Jackson, S.W. and J.R. Hudson. " Flavour from Crystal Malt." _J.
Inst. Brew._ Jan/Feb 1978 v. 84 pp. 34-40.
(3) Manners, D.J. "Starch Degradation During Malting and Mashing."
_Brewers Digest_ Dec 1974, pp. 56-62.
(4) Palmer, G.H., ed. "Cereal Science and Technology." Aberdeen:
Aberdeen UP, 1989.
(5) McGregor A.W. "Current State of Research into Barley
Carbohydrates and Enzymes." in _Proceedings of the Third Aviemore
Conference on Malting, Brewing & Distilling_ ed. I. Campbell. London:
IoB, 1990; pp 10-33.
(6) Blenkinsop, P.G. "A Look at Malt Products." in _Proceedings of
the Third Aviemore Conference on Malting, Brewing & Distilling_. pp.
(7) Bourne, D.T., et al. "Some Factors Influencing the Fermentability
of Malt." in _Proceedings of the Third Aviemore Conference on
Malting, Brewing & Distilling_. pp. 309-312.
Jeff Renner in Ann Arbor, Michigan USA, JeffRenner at comcast.net
"One never knows, do one?" Fats Waller, American Musician, 1904-1943
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