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Questions and Answers
What is the primary role of yeasts in alcoholic fermentation?
What is the primary role of yeasts in alcoholic fermentation?
Which microorganism is most commonly used for alcoholic fermentation?
Which microorganism is most commonly used for alcoholic fermentation?
What is the alcohol content range typically found in wine?
What is the alcohol content range typically found in wine?
Which fruit is primarily used to make wine?
Which fruit is primarily used to make wine?
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What is the term used to describe the distinctive character of wine based on its place of origin?
What is the term used to describe the distinctive character of wine based on its place of origin?
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What is the primary role of Saccharomyces cerevisiae in wine-making?
What is the primary role of Saccharomyces cerevisiae in wine-making?
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Which of the following factors contributes to the development of wine's distinctive character?
Which of the following factors contributes to the development of wine's distinctive character?
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What process follows the mashing of malt in beer production?
What process follows the mashing of malt in beer production?
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Which statement accurately distinguishes lager from ale?
Which statement accurately distinguishes lager from ale?
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During which winemaking step is the wine typically racked?
During which winemaking step is the wine typically racked?
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Study Notes
Food And Fermentation Part 2
- Course: SC/NATS1560 3.0 Understanding Food
- Instructor: Dr. Angela Cope
- Year: 2024
Learning Objectives
- Describe alcoholic fermentation, defining "wild yeasts" and identifying the most common microorganism used (Saccharomyces cerevisiae).
- Detail common drinks and foods made via alcoholic fermentation, their raw materials, and processing methods. Examples include wine, beer, and bread.
Alcoholic Fermentation
- Yeasts convert sugars into ethyl alcohol and carbon dioxide.
- Ethyl alcohol (ethanol) is a psychoactive substance and narcotic.
- Moderate amounts cause mild inebriation; larger amounts lead to intoxication and addiction.
- It's an antiseptic, killing harmful microbes.
- "Wild yeasts" or natural starters are also used.
Wine I
- Primarily from Vitis vinifera grapes (over 1300 varieties).
- Examples: Cabernet Sauvignon, Merlot, Pinot Noir, Syrah, Grenache, etc.
- "Terroir" (place of origin) influences distinctive character.
- Alcohol content: 8%-14% ABV.
- Also made from other fruits (e.g., cherries, dates, apples, pears).
Wine II (Vinification)
- Grapes are crushed into must.
- Wild yeasts or Saccharomyces cerevisiae convert sugars into CO₂, ethanol, and aromatic molecules.
- Skins are steeped to give wine colour and stronger flavours.
- Wine is racked to remove dregs (dead yeasts and skins).
- Filtered and fined.
- Aging in oak casks imparts complexity to flavour.
- Finest wines can age up to 30-40 years.
Test Review - Microorganism
- Most used microorganism for alcoholic fermentation: Saccharomyces cerevisiae.
Test Review - Wine Character
- Contributing factors to wine's distinctive character: Terroir, steeping of grape skins, and aging in casks.
Beer
- Made from grains (barley, wheat, oats, rice, corn).
- Grains become malt through sprouting and kilning.
- Amylase enzymes convert starch into sugars.
- Hops are added to the wort for flavour.
- Yeast converts sugars into CO₂ and alcohol.
- Alcohol content: 4-5% (up to 10%).
- Ale: warm brewing (21-25°C), top fermentation with Saccharomyces cerevisiae.
- Lager: bottom fermentation (6-8°C), Saccharomyces uvarum.
Brewing Beer (Process)
- Malting the grains
- Kilning and grounding the malt
- Mashing the malt
- Adding hops and boiling the wort
- Adding yeast and fermenting
- Conditioning (re-fermenting, fining, centrifuging).
Test Review - Lager vs. Ale
- Key differences between lager and ale include bottom vs. top fermentation, cold vs. warm brewing, and differing yeast species (Saccharomyces uvarum vs. Saccharomyces cerevisiae).
Bread
- Made from milled grains (flour).
- Hard wheat has high gluten content (glutenin and gliadin).
- Amylase breaks down some starch into sugars.
- Flour + water = dough.
- Glutenin + gliadin form gluten, making dough elastic.
- Kneading develops gluten structure.
- Leavening using yeast (wild or Saccharomyces cerevisiae).
- Yeast converts sugars into CO₂ and alcohol, causing dough to rise.
(Butt) Bread
- Heat solidifies stretched dough.
- Sourdough uses a starter containing wild yeasts and lactic acid bacteria.
- Baking completes and stops fermentation.
- Surface water evaporation and Maillard reactions form crust and crumb.
Unfermented Breads
- Unleavened flatbreads include matzo, lavash, rotis, etc.
- Made from corn flour, and others.
- Quick breads are leavened by CO₂ producing chemical reactions without fermentation.
- Examples: cakes, scones, cookies, pastries, biscuits.
- Chemical leavening agents include baking powder, baking soda, and ammonia salts.
Test Review - Sourdough vs. Non-Sourdough Bread
- Sourdough bread uses a starter (wild yeasts and lactic acid bacteria) to leaven.
- Non-sourdough bread doesn't use a starter as it is typically leavened with other techniques like chemical leavening.
Home Review
- Milk curdling and its relation to cheese production.
- Mold's effect on cheese.
- Three examples of each main type of fermentation.
- Malt and its use in beer brewing.
- Key differences between wine and beer brewing.
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Description
Explore the fascinating process of alcoholic fermentation in this quiz. Discover the role of wild yeasts, the most common microorganism Saccharomyces cerevisiae, and the varieties of wine produced from grapes. Test your knowledge on the drinks and foods created through these methods.
