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Hi all,

After a week or so I have decided to summarize the comments I received from
various people on vinegar.  I have certainly learned a lot, and I have, for
now anyway, decided to try foods with distilled vinegar.  So far I have not
had any immediate problems.

Thanks to all who replied.  Here are the comments:

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Did a little online research--vinegar of produced from an alcohol--(can be a
gluten-based starch--just like alcohol.)  And while it shouldn't come through
in the distillation process--the acetic acid is only a small part of the
actual ingredients in vinegar.  Like alcohol, maybe we need to worry more
about what the remaining 96-92% is. After red wine vinegar is still looks like
red wine, so something must be added in addition to acetic acid.    (Heinz
distilled vinegar is supposed to make from corn.)

Taken from aol encyclopedia--
Vinegar (from the French vinaigre, "sour wine") is an acidic liquid obtained
from the fermentation of alcohol and used either as a condiment or a
preservative. Vinegar usually has an acid content of between 4 and 8 percent;
in flavor it may be sharp, rich, or mellow. Vinegar is made by combining
sugary materials (or materials produced by hydrolysis of starches) with
vinegar or acetic acid bacteria and air. The sugars or starches are converted
to alcohol by yeasts of the genus Saccharomyces, and the bacteria make enzymes
that cause oxidation of the alcohol.
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Ed
I think it is to do with what the vinegar is made from
rice, wine, beer, barley etc.  I'm guesing but I think that
some vinegars contain malt.
I've heard that balsamic vinegar, apple and wine vinegars are OK for us.
Let me know if you find something other than this.
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Ed,

I have no medical basis for this statement but here goes,

If I ingest anything with distilled vinegar in it, it invokes the same response
from ingesting gluten.  I also seem to have trouble with salad olives packed in
water with acetic acid.
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Distilled vinegar is not distilled.  The name merely means that it is made
from distilled alcohol.  This is done in a fermentation process in which
the fermenting bacteria, a species of Acetobacter, oxidizes the added
alcohol to acetic acid.  The fermentation mixture is filtered and diluted
to give an acetic acid concentration of about 5%.  This is vinegar.  It
does contain nitrogenous material which is in part derived from the
nutrient mixture added to the fermentation in order to keep the
Acetobacter growing, and in part from those bacteria that die and
disintegrate during the fermentation.  This acetic fermentation is common
to all vinegars so that they all contain the same kinds of nitrogenous
'contaminants', although in differing amounts.
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Vinegar is not a name for acetic acid but it is a major component.

My understanding with vinegar is that it is "better safe than sorry"
there shouldn't be any gluten left by the end of the process. Vinegar can be
made from many sources, including wheat, and unfortunately the source isn't
always specified.
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Dear Ed,

It all depends on how paranoid you are.  Your description
of vinegar is in principle accurate.  The cheapest way of
making it is to distill from various acetic acid sources
some of which may be of non-GF origin.  Now the paranoid
bunch have discovered that some tiny amounts of gliadins
CAN cross during bulk distillation (we are talking of parts
per billion or less).

The real NO-NO is brewed vinegar.  This can be made with
any grain which is first brewed to give alcohol then has
Acetobacter spp added to convert this to alcohol.

The CERTAIN way to avoid all problems is to use wine
vinegar.

I hope this helps.
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Ed,
Concerning gluten in vinegar, I personally do not think there
is any, at least not enough to have any effect on a celiac.  There is a
wide-spread belief that because a small part of the alcohol made in this
country may come from the fermentation of wheat starch, some surviving
gluten or gluten peptides will somehow be carried over in the distillation
process to contaminate the final product.  Since I do not feel that the
celiac diet should be restricted any more than is necessary, I posted a
rather long statement on this subject about two years ago.  If I can find
a copy in my files and if I do not get into trouble in trying to transfer
it, I will add it to this note.


ALCOHOL AND VINEGAR - SOURCES OF GLUTEN? It has been common practice among
celiac support groups and others offering advice on gluten-free diets to
proscribe white (distilled) vinegar and alcohol as potential sources of
gluten.  The assumption is made that any product  manufactured from a
gluten-containing grain is probably contaminated with gluten proteins or
peptides.  But to those with some chemical training (myself plus others
who have posted comments on this subject in the past), distillation is a
highly effective method for separating volatile substances such as alcohol
from non-volatiles such as proteins or peptides.

Vinegar, especially white vinegar, is a common ingredient in commercially
prepared foods.  Because I object to dietary restrictions that are
unnecessary and that further limit an already restricted diet, I have
tried to learn something about the manufacturing process.  The following
summary is for others who might like to know how white vinegar comes into
being and what the level of gluten contamination, if any, is likely to be.
My sources of information have been the biotechnology literature and
telephone contacts with knowledgable people in the industry.  I personally
have had no hands-on experience in vinegar making.

FROM GRAIN TO STARCH TO FERMENTABLE SUGAR:  White (distilled) vinegar is
of course not distilled, but the ethyl alcohol from which it is made is
distilled from a yeast fermentation mixture.  (In the UK, however, I
believe that 'distilled vinegar' has a different meaning, that it is made
from malt and that it is in fact, distilled.)  In most of the world,
molasses, which can be fermented directly by yeast, is the major source of
alcohol.  Alcohol is also made synthetically from petroleum products but I
do not believe that alcohol from this source is much used in the food
industry.  In the U.S., starches derived from grains are the major source,
mostly (about 85%) from corn.

Starches are mixtures of large straight and branched chain polymers of the
simple sugar, glucose.  Since yeast is incapable of fermenting starches,
whether from corn, wheat, potatoes or any other source, the grain starches
must be pre-digested with amylases, enzymes that are capable of splitting
the starch molecules into smaller fragments.  Depending upon the nature of
the amylases, the end products are usually maltose (a disaccharide of two
linked glucoses), some free glucose, and small amounts of assorted
dextrins (small polymers of more than two glucoses).  In the brewing
industry, the source of the amylases is usually barley malt, barley that
has been allowed to sprout until the amylases and proteases needed to
digest the nutrient stores in the seed have developed and then heated
enough to stop the sprouting without inactivating the enzymes.  For
industrial alcohol, including the food industry, it is common to replace
malted barley with cheaper,  partially purified amylases prepared from
bacteria (several species of Bacillus can be used) and/or a mold such as
Aspergillus niger or Aspergillus oryzae.

ALCOHOLIC FERMENTATION:  After the starch is largely transformed by the
amylases, yeast is added and the temperature adjusted to initiate
fermentation.  The small  polymers in the digest such as maltose
(glucose-glucose) and maltotriose (glucose-glucose-glucose) are hydrolyzed
by the yeast cells to glucose.  Glucose is then converted by fermentation
to ethanol and carbon dioxide, releasing energy in the process which is
used by the yeast for growth.  Fermentation results in conversion of
roughly 90% of the original starch to alcohol plus smaller amounts of
other volatile products such as aldehydes, ketones, fusel oils (higher
alcohols), phenol derivatives, and esters.  These volatile contaminants
which vary with the yeast strains used and with the bacterial contaminants
in the fermentation mixture contribute significantly to the flavors of
alcoholic beverages but must be removed in the production of purified
neutral spirits.

ALCOHOL IS PURIFIED BY DISTILLATION:  After fermentation, alcohol and
other volatiles are separated from the non-volatile components by
distillation.  There is often a first crude distillation in which the
fermentation mixture is boiled and the vapors are condensed back to a
liquid phase that contains about 50% alcohol plus other volatile products.
While vigorous boiling can drive off microdroplets of the pot liquor (that
contain non-volatile components) along with the alcohol containing vapors,
industrial fractionating stills are built as tall refluxing columns with
sections of transverse plate barriers that are designed to trap entrained
droplets followed by multiple plates to rectify the vapors, i.e., to
concentrate the alcohol, separate it from the other volatile constitutents
(and purify them as byproducts), and to act as a further barrier against
non-volatile material.  The problem for the distiller is not the
relatively simple task of avoiding carry  over of the non-volatile
material in the distilling pot, but rather the separation of the various
volatile products from one another.

IS THERE NITROGENOUS CONTAMINATION IN THE DISTILLATE?  I spoke to an
official of a firm in Iowa that provides U.S.P. grade 95% ethanol to Heinz
and other vinegar producers.  I was informed that their product which
undergoes repeated distillations contains no detectable nitrogen using an
assay whose limit of detection is 0.1 parts per million.  Assuming that
all the hypothetical nitrogenous impurities are protein or peptide, this
limit level corresponds to about 0.7 mg protein per liter of 95% alcohol.
The alcohol undergoes about a 20-fold dilution in its conversion to
vinegar (4 to 5% acetic acid), so that, if all of the hypothetical protein
survives the acetous fermentation, its final concentration is less than
0.035 mg per liter of vinegar.  This worst case scenario represents the
limit of detection; the actual amount present may be far less, and if it
exists, it may have originated from yeast protein (non-gluten) as well as
from seed protein.

IS 0.035 mg/liter DANGEROUS?  Assuming that the maximal daily consumption
of vinegar by an average person is of the order of 30 ml ( 6 teaspoons),
the daily dose of protein or peptide originating in the yeast fermentation
mixture would be less than 0.001 mg (1 microgram).  The significance of
this maximum level can be judged by comparing it to the estimated gluten
level in European GF diets that are based on wheat starch from which the
gluten has been removed by washing (see the March 16 summary by Bill Elkus
of a CelPro discussion of a possible gluten tolerance level).  Estimates
of residual gluten in these "gluten-free" diets are in the range of  4 to
40 mg per day.  To reach the lower estimate of this possible "tolerance"
dose would require a daily consumption of at least 100 liters of white
vinegar.  This might well be dangerous to one's health, but not because of
its gluten content.

THE CONVERSION OF ALCOHOL TO VINEGAR:  I should perhaps comment on the
conversion of alcohol to vinegar, a process in which no distilllation or
elaborate purification is involved.  This process involves a second
fermentation (the alcoholic yeast fermentation being the first) that uses
bacteria, a species of Acetobacter, in place of the yeast.  The procedure
is basically the same whether the alcohol is U.S.P. grade or the crude
alcoholic mixtures in fermented apple or grape juice.  The bacteria in the
vigouously aerated vinegar reactor may be in suspension or on the surface
of wood chips, and the liquid phase contains in addition to the alcohol
source, a nutrient mixture to keep the Acetobacter growing while they
oxidize alcohol to acetic acid.  The nutrient mixture is said to consist
of a variety of salts and some carbon and nitrogen sources such as
glucose, citric acid, ammonium phosphate, some yeast extract or dried
yeast, and hydrolyzed soy flour.  At the conclusion of the fermentation
the vinegar is not distilled, but rather is filtered to remove
microorganisms  and particulate material and diluted to bring the acetic
acid level down from values as high as 15 to 20% to roughly 5%.

CAN GLUTEN BE INTRODUCED DURING THE ACETOUS FERMENTATION?  Since it is
possible that traces of the nutrient mixture could persist into the
finished product, one might  wonder whether gluten-containing grains were
ever used instead of or in addition to soy protein.  I spoke to the
president of one of the major suppliers of nutrient mixes to vinegar
manufacturers.  While he would not give me a detailed list of ingredients
(trade secret!), he assured me that his product is gluten-free, and he
further stated that he was familiar with the composition of other such
products in use on both sides of the Atlantic, and that they were all
gluten-free.  The nutrient mixture is used in cider vinegar as well as in
white vinegar, although in significantly smaller amount.

CAN VINEGAR BE A FOOD ANTIGEN?  I have not searched the allergy or
toxicology literature.  It is evident that with any vinegar there is a
finite content of dissolved solids that consists of inorganic salts, trace
metals, and nitrogenous and other organic materials that could originate
from the nutrient mix or as byproducts of the metabolism, death and lysis
of the Acetobacter, or in the case of cider vinegar, from the variety of
materials pressed out of the apple cores and peels and juice or produced
in the yeast fermentation that yields alcohol for the subsequent acetous
fermentation.  Total solids in vinegars may approximate several percent,
practically equal to the acetic acid concentration,  and there may be
constituents to which some people, celiac or not, are sensitive, but it is
inconceivable to me that a gliadin or a gliadin peptide could be one of
those constitutents.
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Jan 25 '98
Dear Ed:
When my gut protests after  eating vinegar I lose interest in science
and say No thanks when faced with a pickle I did not make myself (rice
vinegar, or cider vinegar, thanks!)
I won't touch the stuff.
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ejh
Chandler, AZ