Allen Paul W. Industrial Fermentations
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BREAD-MAKING
131
3NaHCO
a
+ H
8
(POJ
B
Acid Sodium Phosphoric
Carbonate Acid
2NaHCO
8
+ ^
Acid Sodium Tartaric
Carbonate Acid
NaHCOa + ^
Acid Sodium Cream of
Carbonate Tartar
2NaHC0
8
+
Acid Sodium
Carbonate
3C0
2
+
Carbon
Dioxide
2CO
9
+
Carbon
Dioxide
CO
a
+
Carbon
Dioxide
+
8
Sodium Water
Phosphate
+ 2H.0
Sodium Water
Tartrate
KNaC
JS«O
6
+ H,0
Potassium Water
Sodium
Tartrate
(
Calcium Acid
Phosphate
Carbon
Dioxide
Calcium
Sodium
Tartrate
a
Water
In making baking powder there should be added to every part of
acid sodium carbonate 2J238 parts of cream of tartar (acid potassium
tartrate) or .893 part of tartaric acid, or 2.260 parts of acid caloium
phosphate.
In answer to Liebig's contention that chemical aerating agents
should be used instead of yeast in the making of bread, the bread
technologists of the present time hold that Liebig knew far more about
chemistry than he did about bread. They agree that yeast produces
a bread of far better quality than can be produced by chemical aerat-
ing agents.' The lightness and sweetness of yeast-made-bread and
its inoreased digestibility are factors which greatly outweigh any con-
sideration of the loss of materials by the use of yeast in bread-making.
Parenti in Boll Chem. Farinae (1903), No. 42, gives the following
results of the effect of yeast fermentation on the dough:
" (1) Analysis of bread dough before and after fermentation showed
that the quantity of starch and dextrin suffered no loss.
" (2) The reducing sugars were all consumed except a trace.
" (3) Substances precipitatable in alcohol increased from 2.86% to
4.15%.
" (4) No gluten was found in the dough when it was washed"
Parenti gays that he agrees with Boutroux whose view is that
panary fermentation consists chiefly in the alcoholic fermentation of
the sugars in flour by the yeast added, and in a conversion of the
gluten which in breaking up produces soluble proteins. The origin
of this conversion of protein he finds not in the yeast but in an enzyme
contained in the flour.
Concerning the necessity of fermentation in the manufacture of
good bread J. C. Summers in Bakers' Weekly, March, 1918, gives some
very pointed reasons as follows:
"It is of the greatest importance that doughs ferment in order
that the starches and proteins be split up into simpler forms and gotten
into a condition in which they are more readily assimilated by the
By
courtesy
of
Werner and Pfleiderer
Company.
FIG.
17.—Ageing of flour in storage.
BREAD-MAKING
138
body.
In his
eager desire
for the
loaf
to
possess certain important
physical qualities, such
as
volume, color
of
crust
and
crumb,
and
grain,
the
baker often overlooks
the
important chemical changes that
take place during fermentation, which aocounts
for a
greatly
in-
creased digestibility
of the
finished
loaf.
This very valuable property,
however,
is
increasing
in
importance,
and the day is
certainly
not far
distant when
the
baker,
in
making comparison
of his
bread with that
of
his
competitors, will
not be
satisfied
by
superior physioal properties
alone,
but
will endeavor
to
produce
a
loaf that
is
also superior
in
nutritive properties,
or
food value.
"Without doubt,
the
most important reason
for
fermenting
a
dough
is because
of its
softening effect upon
the
gluten.
If
loaves were
made, proofed,
and
baked from dough freshly mixed,
it
would
be
found that they would
not
show sufficient 'jump'
in the
oven
and
would
be seriously lacking
in
lightness
and
volume.
The
reason
for
this
would
be
that
the
gluten
in the
young dough would
be
tough, strong,
and nonpliable.
In
this condition thig substance would offer
too
much
resistance
to the
gases held within
the loaf, and
they would
be
unable
(although pressing with
the
same foroe when heated)
to
inflate
the
loaf
and
produce that cellular formation
and
give
to the
loaf that
volume that
it
should have.
"During
the
fermentation period
the
acids produced
in
small
quantities have this softening effect upon
the
gluten, having
a
tendency
to render
it
more soluble. When this "developing"
of the
gluten
has
proceeded
far
enough (which requires
a
great skill
on the
part
of the
bakers
to
determine) then
the
doughs 'should
be
taken'
and one
oould
expect,
as a
result, good bread."
R.
E. Lee of The
Fleischmann
Co.
says: "Over fifty
per
cent
of
the
dry
substance
of
yeast
is
protein.
It is
rich
in
nuolein, that wonder-
ful brain
and
nerve food which extracted from yeast, physicians
prescribe
in all
run-down conditions
of the
nervous system.
"It
has
long been known that
the
lack
of
certain substances
in our
diet brings about serious conditions known
as
deficiency disease.
To
these substances
the
name vitamines
has
been given. Yeast
is the
ohief source
of
these jnarvelous, substances without which life would
bjibT
The
rioh bread flavor
of
whioh
man
never tires
is the
result
of the
interaction
of the
products
of
yeast fermentation
and its
importance cannot
be
overestimated."
The particular kind
of
yeast which
is of
interest
to the
bread
maker
is
Saccharomyces cerevisia. However, other kinds
of
yeast
have been used
in
bread making,
as for
instance wild yeast
was
used
before
the
time
of
pure cultures.
Yeasts
are
generally classified
as
follows:
I. SaccEaTomyGes- cerevisiffl. These organisms
are
divided into
three groups: bottom yeasts
of
German beers,
top
yeasts used
in
making English beers,
and
distillery yeasts producing larger amounts
of alcohol than
the
beer yeasts. These
are the
yeasts generally used
in
the
manufacture
of
bread.
134 INDUSTRIAL FERMENTATIONS
II.
Sacoharomyces ellipsoideus. These yeasts are used in the
manufacture of wine and distillery products to some extent. They
are sometimes called wild yeasts as they occur naturally on grapes
in the vineyards. In some countries they are still used in bread
making.
HI.
Torula. These are sometimes called pseudo or false yeaste.
Their only importance to industry is as trouble makers.
There are three different preparations of yeast for bakers, on the
market: compressed yeast, dry yeast, and liquid yeast. Compressed
yeast is made from distillers
1
wort. After the yeast has been collected
from the wort, it is thoroughly washed, and then passed through wire
and silk sieves to free it from foreign materials. After this cleaning
process the yeast is pressed, cut into oakes, and wrapped in tin foil.
Compressed yeast cakes are liable to Btart decomposition unless kept in
a cool place.
Dry yeast is prepared by taking fresh liquid yeast and mixing it
with corn meal, flour, or other starohy materials. This mixture is
dried at carefully regulated temperatures'. If the dry yeast is made
properly it will keep for a long time. However, the percentage of
living cells in dry yeast slowly decreases and it must be remembered
that the number at the start is less than in the case of compressed
yeast.
Liquid yeast is made by collecting the yeast from distillers' wort
and selling it as
1
a concentrated liquid. This yeast preparation has
the disadvantage that it is very liable to be contaminated with bacteria
which cause the development of bad tastes and odors. It is only with
difficulty that uniformity is maintained in liquid yeast.
A kind of yeast used extensively before the innovation of pure
culture yeast cakes was known as "potato yeast" or "wet yeast."
This was made by developing the wild yeast on potatoes or hops.
Either potatoes or hops were made into a decootion with water and
were allowed to stand in a warm place until the wild yeast had had
time to multiply in sufficient numbers. This decoction was added to
the dough in bread making.
The "barms" of Sootland were made by adding malt to a mass of
cooked flour and'water and plaoing the liquor in a warm plaoe to
give the yeast opportunity to multiply. When this mixture began to
foam the froth and scum were taken from the top and 'added to the
bread dough. Jago describes tJie making of "barm" in the household
as follows: "Malt is crushed in warm water, hops and boiling water
are poured over it, then flour is added and the mixture is allowed
to stand until the starch granules of the flour have been burst.open
by the hot water and the starch thus freed has been changed into
sugar by the diastase of the malt. The resulting sweet liquid is drained
from the mixture and is mixed with flour and water, the resulting
sticky mass being subjected to the action of yeast either acquired
spontaneously by exposure to the air (virgin barm) or added in the
foam of a little old barm or ordinary yeast (parisian barm). The
BREAD-MAKING 135
fermentation thus started is allowed to continue several days and
then the barm is ready for use in the sponge."
Salt rising bread according to several writers is bread raised by
the gases produced by yeast and bacteria of corn meal and milk. To
make "salt rising bread," milk and corn meal are mixed and slightly
warmed and then set aside until spontaneous fermentation by the
yeasts and bacteria present is well under way. At thiB .point a spongy
of wheat flour, to which a little salt and water has been added, is
kneaded with the corn meal and milk mixture. The whole mass is
thenkept warm for several hours to raise. The role of salt in the
making of this bread is to prevent high acid producing bacteria from
developing and to make possible the production of a loaf which is not
too sour.
Concerning salt rising bread Paul Richards in Bakers' Helper,
Jan., 1918, says: "In the making of salt rising bread a warm tem-
perature of from 105 to 110 degrees Fahr. must be maintained during
the whole process. The corn meal used should not be sterilized or
kiln-dried (most mills sterilize the corn before grinding). Where it
is practical, grind your own corn for t.hip purpose, using wHite corn.
Put five to six ounces of meal, one-half teaspoonful of soda and a
pinch of salt in a small bowl or pan; add one and one-half pints boiling
milk and one-half pint of boiling water gradually to the meal and
stir to a soft batter. This
1
forms 'the start Set this bowl well oovered
on the top of the bake oven in the sand, or in a pan of warm water,
where the given temperature can be maintained. It is best to set this
ferment in the evening, as it takes about twelve hours to become
light. When this ferment is light, take a larger bowl or dishpan, put
in three quarts of water and sufficient bread flour to make a thick
batter of about the consistency of a griddle cake batter, add the first
ferment and beat well together. Have this batter at the right tem-
perature and set in proving closet, which should be warm and moist.
This sponge will be light in one hour at a temperature of 110 degrees
Fahr. Then make the dough, add three quarts of water, five ounces
salt, five ounces sugar and eight ounces lard; make a medium dough.
Let dough come only so it shows life, then scale and mold in pans.
Set in warm proofer, do not give as much proof as for yeast bread,
and bake as usual."
"In another process the milk is left out in the first ferment, water
is used, with the addition of one pound mashed potatoes, the corn,
potato water, two ounceB of brown sugar, one ounce of ginger. This
is said to hasten the start."
From an extensive study of the biology of salt-rising bread, Kohman
concludes that the leaven in salt-rising bread is not yeast as is in-
dicated by the literature on the subject, but certain bacteria. He
says,
"These bacteria aerate the bread by decomposing certain of its
constituents, principally the sugars, into gaseous products and not,
as has been suggested, by produoing acids which liberate carbon
dioxide from the soda. The microbic flora involved varies greatly,
36 INDUSTRIAL FERMENTATIONS
epending upon the temperature to which the meal is subjected in
atting the 'batter.'
"The organisms that predominate in the batter when it is made
y stirring the meal into boiling milk or water are only occasionally
>und upon plates made from batters that were not subjected to tem-
eratures which destroy non-spore-bearing organisms. The chief
Durce of the bacteria is not the air and utensils as has been sug-
ested in the literature but the corn meal used in making the batter,
ne organism was isolated which in pure culture produces the gas
ecessary to properly aerate bread. This bacterium seems to be a
Lember of the ooli £roup and was never found in batters that were
aated to 76° C. It in all probability belongs to the same group as
le organism described by Wolffin and Lehman, whioh they call
acillus levane. This organism could be propagated in liquid media
ich as TniiV, or could be grown in a batter and subsequently dried,
• be used in the preparation of bread."
This author found that when the temperature of the batter was
•ought to 75° C. or higher most organisms.died exoept certain gas
'oducing spore-bearing organisms which readily produced the gas
hich aerated the bread dough. He found that these organisms could
j cultivated in fresh liquid media and he was" also able to make a
*y starchy material which carried the organism along satisfactorily
id could be used at any time in making salt-rising bread.
He found that the gases produced by these salt-rising bread
ganisms were nearly 2/3 hydrogen and a little more than 1/3 carbon
oxide.
Another kind of bread Bimilar to salt-rising bread studied by
ohman ia
1
"Sauerteig."
He says, "Long before the existence of microorganisms was dis-
ivered, it
WBB
known that when meal or flour and water were made
to a paste it would, after a time, begin to ferment and evolve gas.
lis was early made use of in the preparation of bread and it was
on learned that a portion of the dough could be saved to start the
rmentation in the next baking. This portion of dough would continue
ferment and become sour hence its name 'Sauerteig,' but when
Lxed with fresh flour and water it would again become active and
ise the bread. This method of making bread was, and in some
untries is still, used very extensively particularly in making whole
aal bread, 'Schwarzbrot' and rye bread. It is similar to the salt-
ling method in that the fermentation in both is spontaneous; they
Her however in that the former is started with hot water or milk,
ually boiling, while the latter is made with tepid water. They
ffer also in that salt-rising bread is made from fresh meal each time
lile by the 'Sauerteig' method a portion of fermented dough is saved
: the next baking, and when a housewife or Ijaker i
B
out it is usually
tained from a neighbor. This method of making bread while it is
ide and uncertain compared with the methods of to-day which in-
lve the use of compressed yeast is as would be expected, more
BREAD-MAKINQ 137
certain than the salt-rifling method beoause eaoh time a portion of
dough is saved for the next baking which insures the presence of the
essential organisms although they may be badly contaminated with
others.
"Bread made by the 'Sauerteig^ method differs from salt-rising
in that the gaseous fermentation in the latter is due entirely to
bacteria, while in the former the leavening power owes its origin
primarily to yeaste, and it is a question whether the bacteria present,
some of which are gas formers, are desirable or not; they differ also
in that the latter is made from fresh material each tune, while in the
preparation of the former a portion of dough is saved to start the
fermentation in the next baking."
Use of Wild Yeast.
Wild yeasts were used by man for the preparation of fermented
beverages.and in the making of bread as early as we have historical
records. E. Atwater writes: "A microscopic examination was recently
made of some bread over 4,400 years old found in Egypt with other
remains of a long vanished people. It was made of barley and the dead
yeast cells were plainly visible."
Wheat Substitutes.
The use of wheat substitutes which is an innovation of recent
years has brought new difficulties in the handling of dough during
the fermentation period. However, accurate control measures have
been developed and good results have been obtained. It has always
been considered that the more gluten contained in a flour the more
the fermentation period-should be extended. This theory holds true
when wheat substitutes are used, the total wheat gluten present is
reduced and therefore the period of fermentation must be shortened.
Frank C. Pelky says in Bakers' Helper, "Of all the substitute
flours available for conserving wheat there is none equal to corn.
Chemical analysis shows it to be a very nutritious article of food.
It is the one that we can produce most cheaply and abundantly in this
country. It is
1
an excellent food product. The present process of
milling corn flour is especially adapted for making a flour suited for
blending with wheat flour for bread-making. Good bread can be
made with wheat flour and 20 per cent of added cereals, but we must
remember that the actual effect of putting them into the wheat flour
is to produoe a flour of a softer type, and it must be treated as such
in the dough. In using any of the substitute flours in bread-making,
my advice is to use plenty of yeast and salt and a short fermentation.
"Barley, rice, corn meal, corn flour, corn starch and oats
1
, which
are the substitutes being used to the greatest extent, will accelerate
the fermentation of the dough and therefore must be given a short
fermentation. No certain time can be given for the fermentation,
PLATES
li!^:^*^^^
After
and Laflin, Unimnity of JTonw.
"^^^^J^IZSZ
CompariHon of wheat loaf with wheat substitute loaves.
188
U^
BREAD-MAKING 139
as the time will vary with the quality of the wheat flour used, amounts
and kinds of substitutes, temperature of doughs and shop, and amounts
of other ingredients used. All doughs must be treated cooL For
sponges I recommend a temperature of from 74 to 78 degrees.
"The sponge should be taken when it begins to break. I do not
advise putting cereals in the sponge, but in the dough. The tem-
perature of the dough should be from 76 to 50 degrees. The average
time for the sponge should be 4 hours j for the dough 1 hour. In
making straight doughs I recommend a temperature of 78 to 80 de-
grees.
The time of fermentation will be governed by the temperature
of your dough and the kind of cereals used, but best results will be
obtained with a fermentation time of from 3 hours and 15 minutes
to 4 hours. In making doughs with good, strong wheat flour we could
strike a happy medium, but in using our present flour with added
cereals there is no medium; we must take the doughs on the young
side if we get results.
"The question of which will produce the best loaf of bread with
wheat flour and added substitutes, flour sponge or straight dough,
depends entirely on the wheat flour being used, the size of the pans,
the substitute and the equipment. Good bread can be made with
wheat flour and cereal flours if the following instructions are followed
carefully:
"Treat all mixed flours during fermentation as you would weak
wheat flour. Use enough yeast to insure good, strong fermentation.
Keep your doughs cool. Use plenty of salt^ from 1% to 2 per cent.
Take your doughs on the young side—they cant stand age. Don't
give too much proof in the pans—not over three-fourthB the usual
proof.
Use steam in the oven, and a good, solid heat."
Paul Richards explains why the sponge and dough process of
bread making is best for bread made with mixed' flours. He describes
the procesB as follows:
"While the straight dough method is less troublesome for bread
making (being a process of one operation), when adding other weaker
cereals to wheat breads, cereals which contain no gluten, the sponge
and dough method is preferable. For this reason the majority of rye
breads are made by the sponge and dough or by the sour
dough process. The straight dough method can be used, there is no
doubt about it, but by using the sponge and dough process the
weaker flours may be worked to a better advantage and give more
volume,
"A loaf of good volume always appeals to the baker as well as to
the consumer, and the sponge and dough method has always been
the method to obtain volume. In the making of the old-time New
England breads as much as 2% pounds' of scalded mush was used
for each gallon of dough. The sponge was set with two-thirds of the
liquid, and for doughing the other third of the liquid was added with
the Efcalded cereal, followed by a short-time dough. Sponges and
doughs were treated young. If a small trial baton is to be made (say,
140 INDUSTRIAL FERMENTATIONS
a 12-quart pail batoh) the usual formula would read, using wheat
flour only, like this:
12 qts. water; 6 ounces compressed yeast; 10 ounces salt;
10 ounces sugar; 2 ounces malt extract; 6 ounces shortening; 40 to
42 pounds bread flour.
"If other cereals are to be used singly or in combination with the
wheat flour, take about 5 pounds of corn flour, or oatmeal or barley
flour, reduoing the wheat flour about 6 pounds, as the absorption of
these cereals iB larger, or more water must be used at the doughing
stage. A part of the corn flour may be scalded, say *4 of it, the rest
used for doughing or in the sponge. Very coarse oatmeal is best, used
soaked or scalded, and the barley flour may be used either in the
sponge or soaked in part of the remaining liquid and used for dough-
ing. When making the darker breads, suon as graham and whole
wheat, with admixture of corn or oatmeal or barley flour, these breads
may be sweetened with molasses, saving the other kinds of sugar.
"Set the sponge cool with 2/3 of the liquid and the yeast, using
a part of the wheat flour and other cereals as direoted. Take sponge
as soon as it is ready and breaks, making the dough cool and baking
it young. When the dough is about half up it may be taken and
worked up. The more of the short oereal used, the sooner the dough
must be taken. A little practice will soon teach how long a dough can
stand, and much of this must be left to and depends on the practical
skill of the baker. Treat the dough cool and young; don't save yeast;
do not give much proof in the pans; bake in medium heat; and do not
underbake."
Domestic and Commercial Bread.
Bread, no doubt, ought to be classed into two great classes: home-
made bread, and factory-made bread. These two kinds of bread are
distinctly different and the tendency is to make them still more
different. With the exception of home-made bread the produot of the
especially gifte^Lhousewife, it is safe to say that factory-made bread
is superior.
The making of bread in the home is usually by the straight dough
method, using flour, water, salt, yeast, shortening, milk and some-
times sugar. The sponge method is also uered extensively either as a
short sponge method or as an over night sponge method. The factors
of time, temperature, fermentation and bread improvers are varied
by each different housewife and the bread varies accordingly from
best to poorest. From the microbiologiBt's standpoint, it is appreciated
that many housewives have shown wonderful ability in being able
to produce such fine bread in the home with its variable factors of
humidity, temperature and fermentation. In other words, the making
of bread is complex and the home is seldom equipped for the making
of uniformly good bread. In the home there is no attempt to standard-
ize the factors involved, but to depend upon
HT^II
, in sensing the
proper time to carry out each step in bread-making.