NetNews Usenet Archive 1992 #27/NN_1992_27.iso/spool/rec/crafts/brewing/6916

Text File | 1992-11-22 | 8.4 KB | 165 lines

Newsgroups: rec.crafts.brewing
Path: sparky!uunet!zaphod.mps.ohio-state.edu!saimiri.primate.wisc.edu!ames!pacbell.com!pbhyf!malodah
From: [e-mail] (Martin A. Lodahl)
Subject: Re: Quality of malt extract (_long!_)
Reply-To: [e-mail] (Martin A. Lodahl)
Organization: Pacific * Bell, San Ramon, CA
Date: Sun, 22 Nov 1992 20:43:50 GMT
Message-ID: <[e-mail]>
References: <[e-mail]>
Lines: 153

In article <[e-mail]> [e-mail] (Christopher Mauritz) writes:
>I remember sometime ago a university (in Canada?) did a study on
>malt extracts from many different sources to check for the addition
>of refined sugar.  Apparently, so many of the brands were
>"contaminated" with added sugar that the school refused to publish
>the brand names.
>
>Could anyone here "in the know" provide more details?  I don't have
>the facilities yet to do my own mashing and I'd like to avoid those
>brands which add sugar to the "broth".

I posted something on this to HBD back in '90 or '91.  Here's an
article I wrote on the subject that originally appeared in the newsletter
of the Gold Country Brewers' Association in September '91:

        STUCK ON EXTRACTS, by Martin Lodahl

Have you ever brewed with extracts?  Ever had a "stuck" fermentation?
Then this article's for you, though you probably won't like it.
Because the fact is, malt extracts aren't always what they say they
are, and the homebrewing community is just beginning to wake up to
that fact.

The flap all began in Zymurgy, Vol. 13 #5, Winter 1990.  On
page 15, in Dan Fink's "Brew News" column, was an item describing
a report entitled "Malt Extract:  Relationship of Chemical
Composition to Fermentability", by J. Paik, N. H. Low, and
W. M. Ingledew of the Department of Applied Microbiology and
Food Science, University of Saskatchewan, Saskatoon, Canada
S7N 0W0.  It was presented May 15 1990 to the American Society
of Brewing Chemists, and published in the February 1991 issue
of their Journal.  In his column, Fink reported on their
research, a combination of High Performance Liquid Chromatography
and fermentation studies, which disclosed the disturbing presence
of substantial amounts of glucose syrup, invert syrup/liquid sucrose,
and high fructose corn syrup in the extracts tested, without always
naming those ingredients on the label.  They also discovered poor
fermentation from some extracts, due to a deficiency in the free
amino nitrogen (FAN) content normally provided by barley malt (had
any stuck fermentations lately?).  In the presentation, they did
not identify the extracts tested.

I don't have to tell you what a storm that raised!  The AHA
followed up on it, and again in Dan Fink's column (page 14)
in the Summer 1991 issue of Zymurgy (Vol. 14 #2) they published
a letter from Professor Ingledew in which he said that they
indeed were not planning to release the names of the extracts
tested.  They felt they couldn't be sure whether the adulteration
was done by the manufacturers, or by the distributors.  They also
felt their sample might not be representative, as they had only
tested 44 "lager" extracts, and no "ale" extracts (their
terms).  They didn't feel they had the time or money to handle
either additional testing or possible legal action.  They also
felt that the burden of following up on the problem they'd identified
rested with the brewing industry, through the marketplace.  Then
Professor Ingledew closed with this paragraph:


    In spite of my comments above, I have complete
    confidence in the results obtained in my lab
    by my colleagues.  There is no doubt that
    some manufacturers are profiting from the
    addition of lower cost corn sugars to malt extract.

Well!  Where does that leave us?  Neither of the Zymurgy articles
made it clear what percentage of the extracts tested had been
"juiced", or to what degree.  And, of course, we have no idea
what they were testing.

Recently, Russ Wigglesworth of the San Andreas Malts provided me
with a copy of the original report.  It makes fascinating reading,
and clears up some points raised by the Zymurgy articles.
Significantly, one of the search keywords is "Stuck
fermentation".   The early part of the report describes
the methods used with a level of detail one would expect
of a paper of this nature.  What would interest us is that
"Forty-one malt extracts (all of light lager type) were
purchased from a local brewing supply store.  These malt
extracts were called beer kits, home brew kits, concentrated
brewing worts, or malt extracts for home brewing ... In
addition, one bulk malt extract sample from a malting company
and two bulk malt extract samples from a local brewpub were
obtained".  Red Star Lager yeast was used for all the fermentation
studies.

The first sign of real trouble apparently came when they noticed
that the time required by the extract brews to drop from 12P to
6P varied from a low of 45 hours to a high of 173, compared to
the baseline of 51 hours for the Molsen wort.  In fact, "93% of
the malt extracts had demonstrably slower fermentation rates
than the standard wort", and "correlation between initial FAN
level and fermentation time (to 6P) yielded an r value of
0.75 -- a correlation significant at the 0.01 probability level"
for all you statisticians out there.  For the rest of us, that
means that the slow-fermenting worts were also the ones with low FAN
content.  They experimented with various supplements in various
concentrations to improve this, settling on yeast extract with
added minerals (similar to the commercially available yeast
nutrients, such as "Super Ferment" and others), though noting
that performance was essentially the same at all tested
concentrations, suggesting that saturation is soon reached.  In
short, yeast nutrients appear to be much more helpful than we've
previously been led to believe in conducting fermentation with
extract worts.  That fact is rather surprising:  I, for one,
wouldn't have expected there to be that much difference between
the performance of an all-malt extract wort and an all-malt,
all-grain wort.

The sugar profiles provided the real bombshell.  The researchers
divided the extracts into 3 groups, according to the contents
listed on the labels.  Groups 2 and 3 both had various supplements
and adjuncts listed, and the analyses tracked pretty well with
the labeling.  Group 1 extracts, however, "were labeled at
the source as pure malt extracts".  Of the 21 extracts in that
group, a commendable 14 had carbohydrate profiles "similar to
the standard all-malt wort", which placed them in class 1.  From
here I quote:  "Group 1 class 2 extracts had a D-glucose
concentration 2.7 times that of the standard, with concomitantly less
maltose and maltotriose.  The two possible explanations for this
sugar profile are that wort production was carried out using a
longer saccharification period during the mashing process
(considered unlikely as the final ethanol concentration of the
beer would then be >5%), or that a glucose syrup was added to the
malt extract.  A single Group 1 class 3 extract was found to have
88% of its total sugar content as D-glucose.  Because this sample
did not contain any D-fructose, sucrose, maltose, or maltotriose, this
product was highly adulterated with a high-glucose syrup".  WOW!
A malt extract, without a trace of malt extract!  I am impressed!
They continue:  "Carbohydrate analyses of all Group 1 extracts indicated
that seven of the 21 samples labeled as pure malt extracts were
adulterated with glucose syrup."

So there you have it.  We all know that it's quite possible to
make very good beer using malt extracts, but most of us have at
some time had some problem extract batches.  The degree of
variation this study identifies suggests we may not always have
been at fault.  The study suggests to me a few considerations:

*    If you're not at least partial mashing, add yeast
    nutrient.  It can't hurt, and might help.

*    Don't add sugar to an extract wort.  It may already
    have all it can stand.

*    All extracts are not alike.  If you're using a good
    one, stick with it.


--
= Martin A. Lodahl    [DoD, AHA, NRA]  Systems Analyst, Pacific*Bell =
= [e-mail]        Sacramento, CA, USA     916.972.4821 =
= If it's good for ancient Druids, runnin' nekkid through the wuids, =
= Drinkin' strange fermented fluids, it's good enough for me!!  8-)} =