Leavening
Unit 2
Warm up #1: What is leavening/what are
leavening agents?
• To rise/rising/a raising agent (something that helps doughs
and batters rise)
• Causes a foaming action (gas/bubbles) that often leaves food
porous, lighter and softer
1. Biological
2. Synthetic (chemical*)
3. Mechanical
Yeast (a biological leavening agent) is a living
fungus that has requirements for growth.
• Lab question: What helps yeast (1/2 teaspoon) grow best?
•
•
•
•
BOWL #1 –
BOWL #2 –
BOWL #3 –
BOWL #4 –
Cold water (1/4 cup) and salt (1 tsp)
Cold water (1/4 cup) and sugar (1 tsp)
Warm water (1/4 cup) and salt (1 tsp)
Warm water (1/4 cup) and sugar (1 tsp)
• Cold = 40*-50*
• Warm = 105*-115*
What to record?
• Exact temperature of water for each bowl
• Observations of EACH bowl after 5, 10 and 15 minutes
• Numbers
• Pictures
• Descriptive words
• Your lab report answers 1-8
What feeds the yeast beast?
• BOWL #1 –
• BOWL #2 –
• BOWL #3 –
• BOWL #4 –
Cold water (1/4 cup) and salt (1 tsp)
Cold water (1/4 cup) and sugar (1 tsp)
Warm water (1/4 cup) and salt (1 tsp)
Warm water (1/4 cup) and sugar (1 tsp)
Sugar, moisture and warmth
What Bowl #4 should have looked like…
Warm up #2 - What is yeast?
• A single-celled fungi
• Over 1,500 different species
• Often used as a biological (living) leavening agent
• When people first started using yeast, they were
unaware that they were using living creatures to make
bread
How does yeast leaven?
• Fermentation- A chemical process where sugars are
broken down to produce C02
• As yeast grows, it converts sugar (yeast food) into
alcohol and carbon dioxide (yeast poop)
Different types of yeast
• Active Dry Yeast - is tiny, dehydrated
granules. When mixed with warm liquid (105115F), the cells become hydrated and active.
• Instant Yeast - is a form of dry yeast,
similar to active dry, but with slightly smaller
granules. It doesn’t need to be pre-dissolved
to work properly, so it can be mixed with the
flour before liquid is added.
Different types of yeast cont.
• Compressed Fresh Yeast - comes in small,
square cakes and is moist and perishable. It
must be refrigerated and used within a week or
two of opening.
• Wild yeast - part of nature; lives on many
growing things, including grapes (where it
manifests itself as the powdery sheen on a ripe
grape), and grains.
Pictures of yeast
Cooking with yeast
• Yeast will not die at below freezing temperatures but
becomes “inactive” AKA ZOMBIES!!!
• Yeast should be stored in a cool, dry place, but should
always be at room temperature before being dissolved in
warm liquid
• Yeast is destroyed at temperatures reaching 140 degrees
and higher
Other ways to biologically leaven
• Unpasteurized beer
• Sourdough starter
• Buttermilk
• Kefir
• Yogurt
Group activity
• Compose a list of foods/dishes that use biological
leavening (a food that rises in some way due to
biology)
• Minimum 20 foods
• What biological leaven is used?
• What does the food look like?
• What does the food taste like?
Warm up #3 – What is proofing?
• The final rise of shaped bread dough before
baking
Lab Report - Pizza
• What kind of bread does yeast produce? (texture,
appearance, flavor, color, etc.)
Warm up #4: What is docking?
• Poking holes in rolled-out/formed dough before
applying toppings/filling
• Allows the steam to escape while it's baking
Happy Pi Day!
Group assignment – Due today (turn in box)
• Compose a list of foods/dishes that use biological
leavening (a food that rises in some way due to
biology)
Example:
1. Pizza
• Minimum 20 foods
• Leaven used = yeast
• What biological leaven is used?
• What does the food look like?
• What does the food taste like?
Looks like = Round, light tan
color, porous, lightweight
• Taste = slightly sour/salty
2. Pretzels
•
Gluten
What does gluten have to do with leavening?
• Without gluten there would be nothing to hold the gas/air that
makes bread rise
• Gluten is like a rubber balloon that holds air inside of bread
• Gluten is a combination of water and protein (wheat flour =
Glutenin and Gliadin)
• The stronger the gluten, the more gas it can hold… but stronger
isn’t always best for some types of baked goods
Gluten variations
• Gluten development varies by flour type
• Different flours contain different amounts of
protein (and different kinds)
• A high-protein flour will make a dough with strong
gluten
• This is good for hearty yeast breads
• Low-protein flours create delicate, tender doughs
• This is good for pastries and cakes
Try it out – Gluten lab
Lab question- How does gluten development vary by flour type?
(appearance, texture, elasticity, etc.)
Develop your own gluten from different types of flour
You’ll need:
• ½ cup of each flour (make sure you label the flour)
• 1 piece of cheesecloth
What is Irish soda bread?
How is the bread made?
How is the bread leavened?
Why is it called Irish Soda bread?
Chemical or Biological?
Extension activity: Watch a video on making Irish soda bread – Do you think you can make it at home? Extra credit!!!
So what is flour?
• Grain that has been ground to a fine powder = Flour
• How many different grains are there?
• How many can you name?
• Work as a team to identify as many different types of
grain as you can
19 different types of grain
Different types of flour
All-Purpose Flour: If a recipe calls simply for "flour," it's calling for
all-purpose flour. A mixture of soft and hard wheat, it is the most
versatile of flours.
Cake Flour: The flour with the lowest protein content lacking
gluten-forming proteins. Good for cake / tender baked goods.
Pastry Flour: Has protein levels somewhere between cake flour and
all-purpose flour, Gives ideal balance between flakiness and
tenderness, making it perfect for pies, tarts and many cookies.
Different types of flour cont…
Bread Flour: High in protein- the strongest of all flours. Especially
important for yeasted breads, where a strong gluten is required to
contain the CO2 gases produced during fermentation.
Instant Flour: Is granular and formulated to dissolve quickly in hot
or cold liquids. It will not work as a substitute for all-purpose
flour. It is used primarily in sauces and gravies.
Self-Rising flour: A low-protein flour with salt and leavening
(baking powder) already added. It is especially suited for biscuits,
muffins, cakes, and pastries but never for yeast breads.
How to store flour
• Flour must be kept cool, covered and dry
• Flours should be stored for no more than 6 months*
Exposed flour can cause rancid off flavors
• Do not store flour near soap powder, onions or other
foods and products with strong odors
• Flour properly stored in the freezer will keep well for
several years
• Throw away flour if it smells bad or changes color
Pop Quiz – Answer questions on a separate
sheet of paper
1.
2.
3.
4.
What is leavening?
What is yeast?
How does yeast help bread rise?
What is gluten and why is it important for bread?
Warm up #5 – What is quick bread?
• Bread leavened with anything other than yeast or eggs
• Quicker to make than yeast breads because they don’t
require proofing, temperature checks or climate control
• Cake
• Brownies
• Muffins
• Pancakes
• Scones
• Biscuits
• Cornbread + more
Synthetic/chemical leavening
• Only about 200 years old
• Chemical leavening agents also create expansion by the
release of carbon dioxide (CO2)
• These leavens are triggered by moisture, heat, or both
• Baking Soda
• Baking Powder
• Double Acting Baking Powder
Mini lab: Do you measure up?
• Using a kitchen scale
• Taring
• Unit conversions
• ***DO NOT PRESS HARD ON THE SCALES (they will break)***
• Lab question: What can you conclude about measuring
flour, after completing this lab?
WHAT ARE THOSE??!!
• Saturated fat
• Dextrose
• DATEM
• Distilled monoglycerides
• Thiamin mononitrate
• Aluminum phosphate
• Sodium stearoyl lactylate
Pancake Lab
• Lab report question: Why is the order of operations
important when completing a quick bread recipe?
The science of synthetic leavening
• https://www.youtube.com/watch?v=elCcybU7wx4
Baking Soda
• Baking soda is a chemical called sodium bicarbonate
• It is a base that will react with an acid to make carbon dioxide
• Common acids: buttermilk, cream of tartar or lemon juice
• The products of the reaction are a salt, water, and carbon dioxide
• Mixtures leavened with baking soda require quick handling to avoid
release of most of the gas before baking
• If you use baking soda without an acid your finished product could
come out yellow have undesirable odors and flavors
HUH?
Baking Powder
• A leavening agent made up of baking soda and an acidic salt
• Baking powder is different from baking soda because it contains both
an acid and a base
• When moisture is added the acid and the base react with each other
• Baking powder is used in recipes that are not acidic enough for
baking soda alone
• It’s most commonly used in batter ‘breads’ like pancakes, waffles,
biscuits and scones
Double Acting Baking Powder
• The most widely used synthetic leavening agent
• Has 2 or more acids
• One acid releases CO2 at room temperature
• The other acid releases CO2 when it is heated
• Can replace regular baking powder
Tips for using synthetic leavening
• You need roughly 1 tsp of baking powder per cup of flour in the recipe
you need leavened
• Test if your baking powder is working properly: add a bit of water. If it
fizzes, you know it’s working.
• The fact that baking powder works on its own means that you can
substitute baking soda with baking powder. You cannot, however,
substitute the other way around.
• Baking soda and cream of tartar = homemade baking powder
• For every 1 tsp. of baking powder use 1/4 tsp. of baking soda, and
1/2 tsp. cream of tartar
Assignment - Unit Conversions
Complete the following charts in your journal
Conversion poster – Assignment due 3/28
Create a creative poster displays unit conversions (TSP, TBSP, CUPS, OZ,+)
Posters must have at least 3 colors and 3 images
If you’re working in
pairs there should
be be 4 colors and 4
images minimum
Warm up #6 – Define Yield
• How much a recipe makes
• How many servings the recipe will produce
Calculating yield
• If you know how to calculate yield you can easily customize any
recipe to fit your serving needs.
• Calculating is simple
• It’s New Yield, divided by Old Yield, to get your Conversion Factor.
• Then, you just multiply each ingredient by the conversion factor, …
BOOM, converted recipe.
Yield Practice
Practice on your own
Buttermilk Scones Lab
• Lab report question: What role does buttermilk play
in the creation of buttermilk scones? Would the end
result be any different if regular milk was used
instead of buttermilk?
Mechanical Leavening
• An alternative or supplement to additive leavening
• A mechanical action by which air is incorporated
Creaming
• The process of beating sugar crystals and solid fat
(usually butter) together.
• This mixing integrates tiny air bubbles into the
mixture, since the sugar crystals physically cut through
the structure of the fat.
Whipping
• Using a whisk on certain substances, usually cream or egg
• Creates foam through mechanical action
• This is the method used for sponge cakes
Nitrous oxide
• Often used as a propellant in aerosol whip cream
cans.
• Large densities of N2O are dissolved in cream at
high pressure.
• When expelled from the can, the nitrous oxide
escapes emulsion instantly, creating a temporary
foam in the butterfat of the cream.
Use a Chromebook to complete the following
3 Recipes that use the whipping method
3 Recipes that use the creaming method
Record a list of the recipes in your journal
Watch at least one “How to” video on the recipes you recorded