Name
Culinary Chemistry
Oct. 2, 2017 Li/Ba/Cu
Oct. 3, 2017 K
CW: Investigating Soda Ratios
Ratio-
Activity: What Makes the “Best” Soda?
Citric acid and baking soda react together, and the product of that chemical reaction is carbon dioxide. Carbon dioxide is the gas that makes soda and seltzer bubbly. In this activity, you’ll try different quantities of citric acid, baking soda, and sugar to determine the best recipe for your ideal soda.
*NOTE: tsp = teaspoon*
Part 1:
1. Add 1/8 teaspoon of baking soda to the empty clear cup.
2. Add ¼ tsp of citric acid to the same clear cup.
3. Gently swirl the cup to mix them together.
4. Using the measuring cup, add ¼ cup of water to the clear cup.
5. Use the stirrer to quickly mix the solution together.
6. Pour some of the mixture into each of your personal taster cups, and start the timer for 1 minute now.
7. Taste a little bit of the beverage.
a. Are there a lot of bubbles? Is the liquid mildly bubbly or is it bubbling a lot? Rate the bubbling on a scale of 1–5, where 1 is not bubbly at all and 5 is too bubbly, in theInitial Bubblinesscolumn of the Data Table 1.
b. How does it feel on your tongue? Is the liquid too gritty? Do you find the feeling of the liquid in your mouth pleasant? Rate the grittiness of the beverage on a scale of 1–5, where 1 is not gritty at all and 5 is too gritty, in theInitial Grittinesscolumn of the data table.
***After tasting the beverage, feel free to spit out the liquid. It will not harm you to swallow it, but it might not taste very much like soda yet (mostly because sweetener has not yet been added) and you also do not want to over-acidify your stomach (which could give you a slight stomachache), because there is still more testing to do.***
8. After 1 minute has gone by, take a sip of the beverage again.
a. How are the bubbliness and grittiness after sitting undisturbed for 1 minute? Note how the beverage tastes, and rate the bubbliness and grittiness, using the same scale you used in steps 4–5, in theBubbliness After 1 MinuteandGrittiness After 1 Minutecolumns in the same data table.
Again, if you choose, spit out the liquid.
9. Pour any remaining liquid down the drain. Rinse out both plastic cups and wipe them out with a paper towel. Make sure that there is not any extra baking soda or citric acid in the bottom of the cup that you are using to mix the ingredients.
10. Repeat steps 1–9 three more times, using the amounts of baking soda and citric acid listed in Table 1.
Data Table 1
Amount of Baking Soda / Amount of Citric Acid / Initial Bubbliness / Initial Grittiness / Bubbliness After 1Minute / Grittiness After 1Minute /1/8 tsp. / 1/4 tsp.
1/4 tsp. / 1/4 tsp.
1/2 tsp. / 1/4 tsp.
1 tsp / 1/4 tsp.
Part 2:
11. In the clean plastic cup, re-make the recipe that you enjoyed best from the first section.
12. Add ¼ tsp. of sugar or sweetener to the beverage and quickly stir in the sugar with a stirrer.
13. Taste the beverage and record your observations in the Data Table 2. Is the beverage sweet enough? Rate the sweetness of the beverage on a scale of 1–3, where 1 is not at all sweet and 3 is too sweet. Record this in Table 2.
14. Repeat steps 11-13, but make it with ½ tsp. of sugar.
15. Repeat steps 11-13, but make it with 1 tsp. of sugar.
16. Discard all extra liquid and throw out the plastic cup.
Data Table 2
Sugar / Sweetness Rating / Sweetness Observations /1/4 tsp.
1/2 tsp.
1 tsp.
Questions
1. What type of mixture did you make?
2. According to your data, which combination of baking soda, citric acid, and sugar creates the most enjoyable soda?
3. What stayed the same for every soda recipe?
4. What caused the difference in bubbliness of each recipe in Part 1?
5. What made the difference in flavor in Part 2?
6. How would you describe the ratio of sugar to water in each recipe in Part 2?
7. How would you describe the ratio of baking soda to water in each recipe in Part 1?
Particle Nature of Matter 9