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Chapter 4:
Fermentation
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Fermentation
Fermentation = the breakdown of compound molecules in organic substances under the effect of yeast or bacteria
It starts when flour and water come into a contact
In baking, it occurs when some of the sugar or glucide is converted into alcohol and carbon dioxide under the effect of commercial or natural yeast and bacteria
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Fermentation
Sugar Transformation
Flour contains various types of glucides
More complex glucides must be degraded by enzymes or organic substances
Less complex glucides are used as is
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4. Fermentation: Sugar Transformation
Complex Glucides
Saccharose and Maltose
Represent 1% of flour
During the first 30 minutes of fermentation time, Enzyme breaks them down into simple sugars
Saccharose breaks down into glucose and Fructose
Maltose breaks down into glucose
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5. Fermentation: Sugar Transformation
Very Complex Glucides
Starch
Represents 70% of flour
Two types: Amylose and Amylopectin
Amylose is broken down into maltose by beta amylase enzyme
Amylopectin is broken down into dextrin by alpha amylase enzyme, and dextrin is degraded into maltose
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6. Fermentation: Sugar Transformation
Simple Glucides
Glucose and Fructose
Represent 0.5% of flour
First sugar to be used in the fermentation
Used within the first 30 minutes of the fermentation process
Easy transformation to alcohol and carbon dioxide
Starch is damaged during the milling process
Damaged parts of starch (from the milling process) absorb water, and triggers the enzymatic activity
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Fermentation
Importance of Enzymatic Balance in the Flour
Alpha and Beta amylase enzymes naturally present in the flour
The germination of the wheat varies the amount of alpha amylase
When sprouting, the germ sends enzymes to the endosperm, which transform the complex components into smaller nutrients that are immediately usable by the germ
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Fermentation
Effects of Fermentation Activity on Dough
Rising of the dough due to the carbon dioxide production
Internal accumulation of gas stretches the gluten structure of the dough
The dough’s impermeability, extensibility and elasticity, the gluten is capable to retain the gas
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Fermentation
Effects of Fermentation Activity on Dough
Acidification of dough
pH lowers due to the production of organic acids
Delays staling of the dough and increase shelf life
More elasticity, less extensibility
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Fermentation
Factors Affecting Fermentation
Amount of yeast
Amount of Salt and sugar
Temperature
Dough pH
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11. Fermentation: Factors Affecting Fermentation
Amount of Yeast
The amount of yeast must be limited to control fermentation
Temperature
Yeast is highly active at higher temperature, and slower at lower temperature
Desired Dough Temperature: 76°F
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12. Fermentation: Factors Affecting Fermentation
Amount of Salt and Sugar
Salt slows down fermentation activity
Generally, salt is 2% of the flour weight
A small amount of sugar (5%) speeds up the fermentation process (simple sugar = nutrients)
A larger amount (13% or more) will slow down fermentation
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13. Fermentation: Factors Affecting Fermentation
Dough pH
Commercial yeast works best when pH is 4-6
Natural yeast prefers lower pH
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Fermentation
Relationship between Fermentation and Dough Handling
Bread characteristics are determined by the baking process
Baking process: Dough Handling (mixing, dividing, shaping, scoring, baking) and Fermentation Time (dough evolves by itself)
The baking processes are interconnected, and one affects on others
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Fermentation
Relationship between First Fermentation and Mixing
A long fermentation provides increased flavor and shelf life to the final product
During mixing, the hook develops the gluten by stretching and folding
The longer the mixing, the stronger the gluten
Mixing time needs to be decreased to have a long fermentation time
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Fermentation
Relationship between First Fermentation and Mixing
Short mixing time limits oxidation of the dough
Requires folding technique to compensate the under-developed gluten
Folding reorganizes the gluten structure
It expulses the gas accumulated in the dough
Relationship between First Fermentation and Dividing
Gluten strands become more fragile – avoid damaging the dough during dividing
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Fermentation
Relationship between First Fermentation and Dividing
Gluten strands become more fragile – avoid damaging the dough during dividing
Relationship between Dough Characteristics and Pre-shaping
If the dough have insufficient or excessive strength, it can be corrected during pre-shaping
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Fermentation
Relationship between Dough Characteristics and Shaping
The dough characteristics can be balanced during shaping: last opportunity
Relationship between Final Proof and Shaping
Dough shaped through machine takes longer time to ferment
Hand-shaped dough takes shorter time to proof
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Fermentation
Relationship between Dough Characteristics and Scoring
Over-proofed dough: shallow scoring
Under-proofed dough: deep scoring
The way to score changes the appearance of the final product: choose the scoring according to the dough characteristics
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Fermentation
Preferments
Dough or batter created from a portion of the total formula’s flour, water, yeast and sometimes salt
Improves bread quality, strength and aroma
Types of Preferments
Pre-fermented Dough
Poolish
Sponge
Biga
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Types of Preferment
Pre-Fermented Dough
Dough made with flour, water, yeast and salt
A piece of dough from previous mix can be used as a pre-fermented dough
Poolish
Derived by Polish bakers
Choice of preferment for baguette dough
100% hydration
Provides mild acidity and extensibility
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Types of Preferments
Sponge
Used for pan bread production in England
Popularly used in enriched dough
Improves flavor and strength of the dough
Biga
From Italy
Traditionally contains 50-55% water, but it varies
Provides dough strength
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Preferments
Advantages and Drawbacks of Preferment
Advantages
Gas Production
Alcohol Production
Acid Production
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24. Fermentation: Preferments
Advantages and Drawbacks of Preferment
Drawbacks
Additional work required
Extra space for storage (refrigerated/room temp)
Potential inability to plan exact amount of preferment
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Preferments
Technical Considerations
Mixing Preferments
Stiff Preferment: Mix on first speed for 5 – 8 minutes
Liquid Preferment: Mix with a paddle attachment
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26. Fermentation: Preferments
Technical Considerations
Incorporation in the Final Dough
Timing and Quantity
Secondary Effects of Preferment
Enzyme provokes sugar and protein degradation
Amylase and Protease
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Fermentation
Sourdough
By accident, first created in Egypt between BCE.
General Sourdough Process
Start a culture of microorganisms and increase the quantity to ferment the dough
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Sourdough
Microorganisms Involved in the Sourdough Process
Yeast and Bacteria
Found in air, water, flour, etc
Yeast transforms simple sugars to alcohol and gas
Bacteria converts certain sugars into lactic and acetic acid
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Sourdough
Starting a Culture
A controlled culture of microorganisms requiring food (flour), water and oxygen
Organic Flour and the addition of rye or whole wheat flour will increase micro organism activity
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30. Fermentation: Sourdough
Culture Elaboration
Both aerobic and anaerobic activity of microorganisms (yeast and bacteria)
Stronger flora flourish and become established (natural selection)
Culture is “fed” at predetermined intervals to maintain activity of microorganisms
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31. Fermentation: Sourdough
From Starter to Levain
Starter is elaborated until needed in formula
Levain is the preferment to be used to leaven final dough
If more activity is needed to achieve the mature levain, the quantity of starter may be increased in the levain feeding
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32. Fermentation: Sourdough
Perpetuating the Culture
Option 1: remove a piece of the final dough before the addition of the salt
Option 2: increase levain quantity and remove required quantity of started to perpetuate
More consistent results occur when the starter is taken from the levain
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33. Fermentation: Sourdough
Factors Affecting Culture Characteristics
Hydration: water content affects flora activity
Stiff culture will have tendency to develop more acetic acidity (more acidic flavor)
Liquid culture will increase the production of lactic acidity (less acidic flavor)
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34. Fermentation: Sourdough
Factors Affecting Culture Characteristics
Temperature
85°F (29°C) to 90F (32°C) favors bacterial activity and the production of lactic acidity, but fermentation is more difficult to control
77F (25°C) optimizes fermentation activity, the development of the dough, and the production of aromas.
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35. Fermentation: Sourdough
Factors Affecting Culture Characteristics
Flour
Enzyme and bran content determine the amount of simple sugar and minerals available for the microorganisms
Higher extraction flours provide better activity and higher acid production
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36. Fermentation: Sourdough
Factors Affecting Culture Characteristics
Salt
0.1 percent can be beneficial for a culture with high protease activity
More than 0.1 percent can inhibit the activity of some microorganisms.
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37. Fermentation: Sourdough
Maintaining the Culture
Consistency
Feedings should be regulated: ratio, type and temperature of ingredients. Mixing and storage.
Sanitation
Always use clean equipment and practice good hygiene.
Contamination
Prevent contamination from commercial yeast.
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38. Fermentation: Sourdough
Troubleshooting Sourdough Culture
Too little Acidity/Too much Acidity
Lack of development in the bread
Lack of strength in the levain.
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39. Fermentation: Sourdough
Use in Final Dough
Proportion of levain
Related to dough and bread characteristics
Strength
Flavor (acidity level)
Use for different types of product
Possibility to develop different cultures with different characteristics
Whole Wheat, Rye
Sweet dough
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Fermentation
Fermentation Process Conclusion
Fermentation affects flavor, appearance and keeping qualities of bread.
From poolish to sourdough, the baker has a lot to consider in terms of flavor, production schedule, and technical considerations.
The baker must learn to evaluate dough at all stages to have a solid understanding of the product and end subsequent end results.
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Retarding Process
Retarding:
stopping the fermentation of the dough at various points in the process
Technical Considerations
Temperature
Gas Production
Gas Retention
Natural Dough Degradation
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42. Retarding Process: Technical Considerations
Temperature
Ferments in baking are sensitive to temperature.
Optimal temperature for fermentation is 74°-80°F.
At lower temperatures, ferments slow down their metabolism.
When the temperature reaches 40°F (4°C), ferments become dormant and most activity is stopped.
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43. Retarding Process: Technical Considerations
Gas Production
Depends on temperature of retarding process and quantity of yeast.
Freshness and quality of the yeast is important.
In a sourdough process, gas production will depend on the culture fermentation activity.
Liquid vs. Stiff cultures
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44. Retarding Process: Technical Considerations
Gas Retention
The goal of the retarding process is to delay as long as possible the point where the gluten reaches maximum extensibility and breaks under the pressure of the gas.
A short first fermentation time is necessary to delay the point where the dough reaches its gas retention limit.
Flour with low starch damage slows fermentation activity.
To delay gas production at the beginning of the process, the DDT is 73°F (23°C).
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45. Retarding Process: Technical Considerations
Natural Dough Degradation
Occurs when flour and water are put in contact and it continues as the fermentation progresses.
Most dough degradation happens because of protease.
To delay degradation start with dough that is strong enough to withstand retarding.
Some adaptations can be made during mixing.
Hydration can be slightly lower
Stiffer dough will provide a stronger gluten structure.
Mixing time must be calculated to sufficiently develop the dough and obtain a strong organized gluten structure.
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46. Retarding Process: Basic Retarding Techniques
Delayed First Fermentation
After mixing, retard dough at 45°F (7°C) to 48°F (9°C). The retarding time can last from 12 to 18 hours.
After retarding, take the dough out of the retarder and divide it right away, or wait about 1 hour before scaling.
Divide and preshape as normal. A longer resting time will be necessary to allow the dough to warm up and restart fermentation.
Complete normal shaping and final proof and bake at the usual temperature and time
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47. Retarding Process: Basic Retarding Techniques
Delayed First Fermentation: Advantages
At 45°F (7°C) to 48°F (9°C) gas and acidity production is still happening at a lower rate but for a longer period of time.
When good quality flour is used, there is no need for dough conditioners such as ascorbic acid, keeping the product labeling cleaner.
Because the dough is retarded in bulk before shaping, no blisters are formed during baking.
The baker can organize production to offer customers fresh bread all day long without mixing too many batches of dough.
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48. Retarding Process: Basic Retarding Techniques
Delayed First Fermentation: Drawbacks
This technique requires a retarder with enough capacity to store a large amount of dough.
The bread cannot be baked immediately after retarding. Three to four hours are necessary to divide, shape, proof and bake the bread.
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Retarding Process
Slow Final Proof
Mix to achieve between an improved mix and an intensive mix
The amount of fresh yeast: 0.8 to 1 percent.
A longer fermentation time calls for a lower percentage of yeast.
Preferment is advised, and the DDT is 73°F (23°C).
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50. Retarding Process: Basic Retarding Techniques
Slow Final Proof
Method
After mixing, allow the dough to ferment 20 to 30 minutes and then divide, preshape and shape as normal
Place the shaped dough in the retarder set at 50°F (10°C).
Retard for 12 to 15 hours and bake directly from the retarder
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51. Retarding Process: Basic Retarding Techniques
Slow Final Proof
Advantages
Dough can be baked after removing it from the retarder after 12 hours
Baked after 12 or 15 hours
Plan production to have fresh bread for breakfast and lunch without mixing too many batches of dough
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52. Retarding Process: Basic Retarding Techniques
Slow Final Proof
Drawbacks
Retarding space is required.
15 to 20 ppm ascorbic acid is necessary to reinforce the gluten structure of the dough.
The surface of the loaves can become dehydrated. For this reason, it is important to have a good humidifier system.
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53. Retarding Process: Basic Retarding Techniques
Retarding-Proofing Process
Method
Mix to achieve between an improved mix and an intensive mix
Preferment is definitely advised. DDT is 73°F (23°C)
After mixing, divide and preshape the dough; then allow it to ferment for 20 to 30 minutes. Let it rest for 20 minutes and shape more tightly than usual
Place the shaped pieces of dough in the retarder set at 38°F (3°C) to 40°F (4°C). Retard for 12 to 48 hours
Remove the dough from the retarder and leave it at room temperature for the final proof
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54. Retarding Process: Basic Retarding Techniques
Retarding-Proofing Process
Advantages
Possible to bake right away the next day
Allows better work organization
Better quality of life
Night hours more limited
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55. Retarding Process: Basic Retarding Techniques
Retarding-Proofing Process
Drawbacks
Energy cost
Flour issue
Dough conditioners may be necessary
Equipment considerations
Floor space
Proofer retarder needed
Good humidity regulation in proofer to avoid crusty dough
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Retarding Process
Sourdough in the Retarding Process
Sourdough is beneficial to the retarding process
Higher levels of acidity reinforces the strength of the dough
Dough conditioners are not typically necessary
Rye and whole-wheat flours can easily be used in the retarding process
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Retarding Process
Equipment
Retarders or proofer-retarders
Temperature, humidity production, and air diffusion
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Retarding Process
Retarding Conclusion
Fresh product all day long
Enables more diversified product line
Better work organization
Better quality of life
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Dough Strength
Balance among three main physical dough characteristics
Extensibility
Property of the dough to be stretched
Elasticity
Property of the dough to return to its initial position after being stretched
Tenacity
Property of the dough to resist to a stretching action
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Dough Strength
Strong Dough Versus Weak Dough
Strong dough
Lack of extensibility
Excess of tenacity
Very elastic
Weak dough
Excess of extensibility
Lack of tenacity
Lack of elasticity
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Dough Strength
Factors Affecting Dough Strength
Ingredients
Mixing
Fermentation
Handling of the dough
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Dough Strength
Ingredients
Flour characteristics
Protein quantity and quality
Ash content
Treatments
Maturation
Water
Dough hydration
Others ingredients
Fat, sugar, seeds
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Dough Strength
Mixing
Use of an autolyse
Affect the gluten of the dough
Mixing time
Dough development
Dough temperature
Affect fermentation activity
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Dough Strength
Fermentation
Length of the first fermentation
Quantity of dough
Mass effect
Use of preferment
Type
Quantity used in the final dough
Degree of maturation
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Dough Strength
Dough Handling
Dividing and scaling
By hand or by machine
Preshaping
Shaping
Tightness
Scoring
Different scoring patterns
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Conclusion
Fermentation is a critical step in baking
The quality of bread is a result of the type of fermentation
Choices: straight dough, preferments, retarding processes
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