Yeast Doughs - Vocabulary Flashcards
Yeast Doughs: Key Concepts and Substitutions
Scope and Core Concepts
- Yeast dough types
- Learn about yeast
- Functions of yeast
- Types of yeast
- How to select and use yeast properly
Yeast Dough Types
- Lean Dough Products (Very Low Fat & Sugar)
- Examples:
- Hard-Crusted Breads: French, Italian, Kaiser rolls, Pizza
- Soft-Crusted Breads: White/whole wheat breads, dinner rolls
- Rye & Multigrain Breads: May include molasses, caraway
- Rich Dough Products (Higher Fat, Sugar, & Often Eggs)
- Examples:
- Non-sweet Rich Breads: Brioche, rich dinner rolls
- Sweet Rolls: Coffee cakes, breakfast/tea rolls (often with fillings/toppings)
- Laminated Doughs (Fat layered via rolling & folding, flaky texture)
- Examples:
- Croissants: Lower sugar, no eggs (usually)
- Danishes: Higher sugar, often with eggs, fillings
- Artisan Breads (Traditionally made, high quality)
- Emphasis on skill, good ingredients, and craftsmanship
- Homemade feel, minimal preservatives
Yeast: Definition and Function
- Yeast is a one-celled fungus, a living organism.
- Function: Converts carbohydrates in bread dough into
ext{Alcohol (Ethanol)} + ext{Carbon Dioxide}
through fermentation. - Leavening: Carbon dioxide gas produced by yeast is trapped in the gluten network, providing rise and texture to bread.
- Temperature sensitivity: Yeast is sensitive to temperature.
- Preferred development range: 24^ ext{o} ext{C} ext{ to } 35^ ext{o} ext{C}
- Dormant below: 2^ ext{o} ext{C}
- Dies above: 59^ ext{o} ext{C}
Temperature for Yeast Development (Summary)
- Inactive: 34^ ext{o} ext{F} ext{ (2°C)}
- Slow action: 60^ ext{o} ext{F} - 70^ ext{o} ext{F} ext{ (16°C - 21°C)}
- Best activity: 75^ ext{o} ext{F} - 95^ ext{o} ext{F} ext{ (24°C - 35°C)}
- Hydration of instant yeast: 85^ ext{o} ext{F} - 100^ ext{o} ext{F} ext{ (29°C - 38°C)}
- Hydration of active dry yeast: 100^ ext{o} ext{F} - 110^ ext{o} ext{F} ext{ (38°C - 43°C)}
- Yeast dies: 138^ ext{o} ext{F} ext{ (59°C)}
Moisture, Salt, and Texture Control
- Moisture helps yeast cells convert carbohydrates into food by activating them.
- Salt functions:
- Conditions gluten for strength and elasticity.
- Inhibits yeast growth, helping control dough rise.
- Practical effects of salt:
- Too little salt → bland taste, rapid rise
- Too much salt → yeast destruction
- Control factors for texture and flavor of yeast-raised breads:
- Amount of yeast food (nutrients available to yeast)
- Fermentation temperatures (for texture and flavor development)
Types of Yeast (Baker’s yeast)
- Saccharomyces cerevisiae
- Available in three forms:
- Compressed (fresh)
- Active dry
- Instant
Baker’s Yeast: Three Forms
- Compressed Yeast (Fresh)
- A mixture of yeast and starch with ~70% moisture
- Also known as fresh yeast
- Storage: refrigerated
- Appearance: creamy white, crumbly with fresh smell
- Off-flavors/consistency to avoid: sour odor, brown color, slimy film
- Preparation: softened in twice its weight of warm water at 100^ ext{o} ext{F} ext{ (38°C)} before adding to dough
- Optional use: can be added directly to dry mix by some bakers
- Packaging: available in 1-pound (500 g) blocks
- Shelf life: properly stored, lasts 2 ext{ to } 3 ext{ weeks}; can be frozen for 1 month when fresh
- Thawing note: frozen compressed yeast loses about 5 ext{%} of activity when thawed
- Active Dry Yeast
- Moisture has been removed by hot air, rendering the organism dormant
- Rehydration: in lukewarm liquid, approx. 110^ ext{o} ext{F} ext{ (43°C)} before adding to dough
- Packaging: available in 1/4 ext{-oz (7 g)} packages and in 1- or 2.2 lb (0.5 kg or 1 kg) vacuum-sealed bags
- Storage: can be stored without refrigeration for several months due to low moisture
- Storage instructions: keep in a cool, dry place; refrigerate after opening
- Instant Dry Yeast
- Added directly to dry ingredients in bread formulas without rehydrating
- Activation: water in formula activates instant dry yeast
- Temperature sensitivity: destroyed at 138^ ext{o} ext{F} ext{ (59°C)}
- Hydration note: some bakers hydrate instant yeast before use in certain formulas
- In dense doughs (e.g., bagel or croissant dough) instant dry yeast may not fully dissolve during mixing
- Solution if not fully dissolving: moisten yeast in 4$-$5 ext{ times its weight of water}, then deduct this amount from total water in formula
Substituting Yeast (Conversion Ratios)
- Compressed (fresh) yeast × 0.5 = Active dry yeast
- Compressed (fresh) yeast × 0.33 = Instant yeast
- Active dry yeast × 2 = Compressed (fresh) yeast
- Active dry yeast × 0.75 = Instant yeast
- Instant yeast × 3 = Compressed (fresh) yeast
- Instant yeast × 1.33 = Active dry yeast
- Note: These relationships provide flexibility when adapting recipes across yeast forms.
- Equivalently, in equations:
- 0.5 imes ext{Compressed} = ext{ActiveDry}
- 0.33 imes ext{Compressed} = ext{Instant}
- 2 imes ext{ActiveDry} = ext{Compressed}
- 0.75 imes ext{ActiveDry} = ext{Instant}
- 3 imes ext{Instant} = ext{Compressed}
- 1.33 imes ext{Instant} = ext{ActiveDry}
Natural Yeast Leavener: Sour Dough Starter
- Historical context: natural yeast leaveners were used before commercial yeast production
- Composition: simple mixtures of flour and liquid (water, potato broth, milk)
- Wild yeasts and acid-producing bacteria are captured from the environment
- Process: mixture is left to ferment to activate yeast activity
- Usage: fermented mixture is used to leaven bread
- Maintenance: a portion of starter is kept for later use and periodically refreshed with additional flour and liquid to maintain activity
Conclusion (Key Takeaways)
- Yeast is a living organism that ferments carbohydrates to produce CO₂ and ethanol
- CO₂ leavens bread by trapping it in gluten for lift and texture
- Yeast is temperature- and moisture-sensitive; optimal range is 24^ ext{o} ext{C} ext{ to } 35^ ext{o} ext{C}
- Salt strengthens gluten and controls yeast activity for dough rise
- Control factors for texture and flavor include yeast food and fermentation temperatures
- Baker’s yeast is available in three forms: compressed, active dry, and instant
- Proper storage and handling maximize yeast effectiveness and longevity
- Conversion ratios between yeast forms enable recipe adaptation
- Before commercial yeast, natural starters were used and required periodic refreshment
Quick Recap Questions (from slides)
- What is the function of yeast in bread making?
- How does yeast contribute to the leavening of bread?
- What are the optimal temperature conditions for yeast activity?
- How does moisture affect yeast's ability to convert carbohydrates into food?
- What role does salt play in bread making and yeast fermentation?
- What is the scientific name of baker’s yeast?
- Name the three forms of baker's yeast.
- How should compressed yeast be stored and handled for maximum effectiveness?
- What are the conversion ratios between compressed, active dry, and instant yeast?
- What were natural yeast leaveners (starters) and how were they maintained?
- What are the key factors for controlling the texture and flavor of yeast-raised breads?
References
- On Baking: A textbook of baking and pastry fundamentals, Third Edition: Sarah R. Labensky, Priscilla A. Martel, Eddy Van Damme
- https://www.sciencephoto.com/media/799896/view/baker-s-yeast-saccharomyces-cerevisiae-sem
Next Session: Production Stages of Yeast Breads
- Scaling the ingredients
- Mixing and kneading the dough
- Fermenting the dough (Bulk Fermentation)
- Punching down the dough (Knock Back and folding)
- Portioning the dough (Dividing)
- Rounding the portions (Pre shaping)
- Bench Rest
- Make-up and panning (Shaping the portions)
- Proofing the products
- Wash and Scoring
- Baking the products
- Cooling and storing the finished product