Chemistry Week #6

Read the Textbook pp 100-109.

Answer the following…

Kitchen Chemistry Homework #6

Homework Questions:

1. Why can’t you have any egg yolk if you want make meringues?
2. Why are copper bowls best to whip egg whites in?
3. Why can’t you use a plastic bowl to whip egg whites?
4. What physical property describes a foam?
5. What happens to the egg foam when you cook it?
6. Why do we add cornstarch to the custard?
7. How can we prevent the meringue from collapsing?
8. What is the purpose of adding sugar?
9. Typically meringues have cream of tarter added to them. Why don’t you think we don’t have them in our recipe?

The recipe for Friday is…

Mile-High Lemon Meringue Tarts From Women’s Day, February 1, 2001, page 124

Ingredients:

Lemon filling
• 2/3 cup white sugar
• 2 tablespoons cornstarch
• 2/3 cup water
• Yolks from 2 large eggs (reserve whites for meringue)
• 1/3 cup fresh lemon juice (from 1 – 2 lemons)
• 1 tbsp. freshly graded lemon peel (from 1 lemon)
• 1 tbsp. stick butter
• 1 package (4 oz) ready-to-fill single-serve graham cracker crusts ( 6 per package)

Meringue
• Whites from 4 large eggs
• 1/2 tsp Cider Vinegar
• 1/2 tsp. Vanilla extract
• 1/2 cup sugar

Method:

Lemon filling

Whisk sugar and cornstarch in the top bowl of a double boiler to mix.
Whisk in water, egg yolks and lemon juice until smooth.
Place bowl over double boiler, stirring often with the whisk.
Boil, stirring constantly, 1 minute or until filling is translucent and thick.
Remove from heat. Add lemon peel and butter; stir until butter melts.
Pour 1/2 cup into each cracker crust and place on a rimmed baking sheet

Meringue:

Heat oven to 350F.

Beat egg whites, vinegar and vanilla in a medium metal or copper bowl with a whisk until soft peaks form when whisk is lifted.
Gradually beat in sugar, 1 tbsp. at a time, increasing whisking speed and beating well after each addition until sugar dissolves.
Beat 2 minutes longer or until stiff peaks form when beaters are lifted Mound Meringue high on each tart, spread to edge of crust , then swirl with back of a teaspoon

Bake 20 minutes or until meringue is browned an instant-read thermometer inserted in center of meringue registers 160F.

Cool completely on a wire rack, then refrigerate at least 2 hours or up to 8. If you wish to share one, use a small sharp knife dipped in cold water to cut through the meringue smoothly.

Chemistry :: Week 5

We will be examining scones and coffee this week. Please read pp. 549-550, 386-387, 433-441 in the textbook and answer the following questions.

 Scone Specific Questions: 

1. How does vinegar curdle milk? 

2. What is the chemical process that happens when vinegar is added to milk? 

3. What happens to the sugar on top of the scone when you cook the scone? 

4. Why don’t you want to knead the scone dough for a long period of time? 

5. Could you make this scone with baking powder instead of baking soda? If you wanted to use baking powder, what ingredient is not necessary?Why? 

Coffee Specific questions 

1. How and where was coffee discovered? 

2. What are the two types of coffee that are extensively cultivated? 

3. There are four main steps to coffee roasting, first roasting, first crack, pyrolysis, and then second crack. Please describe what is happening at each stage. 

4. How much caffeine is in an average sized cup? 

5. Caffeine has been described as the most widely used drug in the world. What is the main target of caffeine in the body? (think receptor/ligand interaction and identify the target receptor) 

6. What happens when you stop drinking your daily coffee? why? 

7. What are the three main ways that coffee can be decaffeinated? 

8. What contributes chemically to the staling of coffee? 

Chemistry: Week 4

This week we will be studying yeast, salt, and bread. Please read pp. 515-550 in the text book and answer these questions

 Yeast Specific Questions: 

1. What is yeast? 

2. Who was the first scientist to identify how yeast works? 

3. What is the different types of yeast available? 

4. Why do you have to add sugar to the yeast? 

5. What is the yeast’s function in the bread? 

6. What else is the major use of yeast in consumer products? 

Bread specific questions: 

1. Why do you have to let the bread rise twice? 

2. Why do you knead bread dough? 

3. Why do you brush the egg yolk on top of the bread before you bake it? 

4. What chemical reaction causes the elastic bread dough to form? 

5. Why happens if your body can’t digest gluten? 

6. What exactly is gluten? 

Salt specific questions: 

1. What is salt? 

2. What is the purpose in the bread? 

 

Chemistry :: Pancakes

For week three we are looking at the chemistry of making pancakes. Please read pp. 553-554, 46-50, 551, 668-669 in the textbook and answer the following questions and look at our recipe for the week. 

1. Do we really need to add both baking soda and baking powder? Why or why not?

2. How do they make buttermilk?
3. How do you make maple syrup?
4. What is sour cream?

5. Why do you whisk the dry ingredients separately from the wet ingredients?

6. Why don’t you want to over mix?
7. Why does the last pancake you make always taste the best?

Kitchen Chemistry :: Week 2 :: Chocolate

We will be working with chocolate this week!!!

Read the following from the textbook: pp. 694-712, 430-433, 647-52, 674-675, and 533-34.

Answer the following questions

Kitchen Chemistry Homework #2 

Chocolate specific: 

1. Do you enjoy chocolate? Is there a biochemical reason for it? 

2. What are some of the chemicals that contribute to the chocolate taste? 

3. Can we become addicted to chocolate? 

4. What is common to both marijuana and chocolate? 

5. Even though it is unhealthy, can we justify from a health perspective eating chocolate in moderation? 

6. What is the ingredient in chocolate that makes our hearts pound? 

7. Should you feed your cat or dog chocolate? Why or why not? 

Ingredient specific questions: 

1. What is the chemistry behind baking powder? At what temperature does this process become spontaneous (remember Gibb’s free energy equations from thermodynamics?) 

2. What does double acting baking powder really mean? 

3. Why add eggs to the recipe? 

4. What is the difference between brown sugar and white sugar? 

5. Where does vanilla come from and how is the extract made? 

6. What modifications did you make to the recipe? 

Chemistry Day 1

The Chemistry course is going to be based on the MIT class: Kitchen Chemistry

Welcome to the seminar entitled Kitchen Chemistry. This is a Pass/Fail, 6-unit seminar (2 hours of class and 4 hours of reading and homework per week). This seminar is designed to look at cooking from a scientific basis. Each week we will do an edible experiment and look at the science behind how it all works. Not only will chemical principles be examined, but also biochemical, biological, microbiological, and maybe even a little physics. Students are required to attend at least 80% of the classes.
This seminar is designed to be an experimental and hands-on approach to applied chemistry (as seen in cooking). Cooking may be the oldest and most widespread application of chemistry and recipes may be the oldest practical result of chemical research. We shall do some cooking experiments to illustrate some chemical principles, including extraction, denaturation, and phase changes.

From Kitchen Chemistry Syllabus

I need to order the textbooks for everyone. In the meantime, you can visit the course website and watch the intro videos.
https://ocw.mit.edu/courses/experimental-study-group/es-287-kitchen-chemistry-spring-2009/syllabus/

Chem Team

We will meet on Thursday morning around 10:30am. We will do some bonding review and work on examples using the periodic table. We will also research some experiments/demos we can do next week.

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