Chapter 4:

Fermentation

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4

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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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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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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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

1. 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

2. 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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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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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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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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4

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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4

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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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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4

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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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 4000-3000 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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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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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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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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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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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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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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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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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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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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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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4

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

CHAPTER

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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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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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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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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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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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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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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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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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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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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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4

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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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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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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4

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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4

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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4

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

CHAPTER

4

Dough Strength

• Factors Affecting Dough Strength

– Ingredients

– Mixing

– Fermentation

– Handling of the dough

CHAPTER

4

Dough Strength

• Ingredients

• Flour characteristics– Protein quantity and quality

– Ash content

– Treatments

– Maturation

• Water– Dough hydration

• Others ingredients– Fat, sugar, seeds

CHAPTER

4

Dough Strength

• Mixing

• Use of an autolyse

– Affect the gluten of the dough

• Mixing time

– Dough development

• Dough temperature

– Affect fermentation activity

CHAPTER

4

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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4

Dough Strength

• Dough Handling

• Dividing and scaling

– By hand or by machine

• Preshaping

• Shaping

– Tightness

• Scoring

– Different scoring patterns

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4

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