YEAST 1

Question 1

what are yeast breads leavened with

Answer 1

CO2 produced from yeast—
Saccharomyces cerevisiae

Question 2

what temp does yeast bread need to be brought to when making

Answer 2

room temp

Question 3

what do sodium or calcium phosphate slow the growth of in yeast breads

Answer 3

molds and bacteria that cause rope
– bread is internally mushy/stringy
to the point it can be pulled into
ropes

Question 4

whats the sponge method of making bread

Answer 4

yeast is combined with water and
~1/3 flour and allowed to ferment (30-60 min)
*Creates a foamy, bubbly,
mixture (resembles sponge)

Question 5

whats the batter method of making bread

Answer 5

Ingredients combined then beaten to develop gluten
*Used for making hot dog and hamburger buns

Question 6

whats the rapid mix method of making bread

Answer 6

*For use in bread-making machines
*Ingredients poured into machine that mixes and kneads
the dough, allows it to rise, and bakes all in the same pan

Question 7

when is kneading finished

Answer 7

when dough springs
back when pressed or when
translucent “gluten window”
appears when stretched

Question 8

whats proofing

Answer 8

letting the dough rise via fermentation to adequately aerate dough
*Yeast breads often proofed twice

Question 9

when does second proofing occur and whats the purpose

Answer 9

After dough has ~doubled in size, it is punched down and briefly kneaded:
(1) Even out temp,
(2) Break large air bubbles into smaller ones,
(3) Redistribute sugar, yeast, and gluten

• bread doubles in size again which takes about half the time as the first proof

Question 10

what does second proofing produce

Answer 10

a bread with greater volume
and finer texture

Question 11

what does yeast produce CO2 from during fermentation

Answer 11

glucose

Question 12

what happens to pH of bread during fermentation

Answer 12

goes down

Question 13

what does the produced CO2 do

Answer 13

react with water to create carbonic acid

Question 14

what other acids does yeast produce

Answer 14

lactic and acetic acids

Question 15

describe the activity of a-amylase

Answer 15

starch to dextrins

Question 16

describe the activity of b-amylase

Answer 16

dextrins to maltose

Question 17

describe how yeast is very sensitive to temp

Answer 17

Temps too low will ferment too slow
*Temps too high will kill the yeast
if humidity too low, yeast will crack

Question 18

what are proof boxes

Answer 18

special containers
that maintain temp/humidity

Question 19

what will overfemerntation cause

Answer 19

ause overextension of gluten and cell
structure collapse -> low volume
*Can develop sour flavor from acid production

Question 20

what happens if yeast uses up sugar

Answer 20

, Maillard reaction will be reduced
(affecting color and flavor)

Question 21

why is the dark heavy-weight steel the pan of choice to shape after bread is proofed

Answer 21

Promotes golden brown color and
perfect crust

Question 22

what increases browning

Answer 22

brushing with milk or egg wash

Question 23

why are breads scored

Answer 23

Allows even rising without tearing
crust (lets out excess steam)

Question 24

how does oven temp change during baking

Answer 24

oven temp is high (400°F) for the first 10-15 min
and then lowered (350°F) for the remainder

Question 25

what does changing oven temp do

Answer 25

Contributes to oven spring: the quick expansion of
dough during initial baking

Question 26

what happens if oven temp not hot enough

Answer 26

Proteins will not coagulate
*Yeast will continue to ferment causing dough to spill
over

Question 27

what happens to yeast and enzymes during baking

Answer 27

*Yeast are killed
*Enzymes inactivated
*Starch gelatinizes
*Caramelization
*Starch broken down into dextrins (dextrinization)
*Maillard reaction (substrates from added milk, sugar, egg)

Question 28

what happens to alcohol and proteins during baking

Answer 28

*Alcohol from fermentation is vaporized
*Proteins coagulate

Question 29

what happens to starch during baking

Answer 29

*Starch gelatinizes
*Caramelization
*Starch broken down into dextrins (dextrinization)
*Maillard reaction (substrates from added milk, sugar, egg)