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1. Determination of Acidity and Soluble Solids in Three Different Coffee Brands. Leah Block
Amy Ferrero
Sara Gagen
Kayla Sapp
2. Purpose The purpose of this lab is to incorporate techniques learned this semester to create a experiment that pertains to the real world. Using titration methods and solubility, the acidity and soluble solids in three different coffee brands will be determined and compared.
3. Acidity
4. Background Part I Formic
Acetic
Lactic
Pyruvic
Malic
Tartaric
Citric
Quinic
Ferulic
Caffeic
Phosphoric
Chlorogenic
Linoleic
Palmitic
At low levels, bitterness helps tame coffee acidity and adds another favorable dimension to the brew. However, at high levels, a bitter coffee compound can overpower the other components present in coffee producing an undesirable effect.
5. Procedure 1 Standardize NaOH against KHp (0.1M NaOH, 1L)
Prepare sample by weighing 2g of ground coffee in 100mL Erlenmeyer flask with 15mL of 95% ethanol
Sample is filtered and diluted to 10mL
Sample is titrated with standard NaOH using phenolphthalein
Determine amount of mL NaOH needed to neutralize the sample
7. Folgers
8. DunKin Donuts
9. Starbucks
10. Procedure 2 Samples were prepared by weighing out about 10 grams of coffee
Water was brought to a boil, 400mL per beaker
Each sample was then put in a single serve coffee maker and brewed
A 50mL sample of the brewed coffee was placed in an Erlenmeyer flask
A pH meter was calibrated
The sample was titrated with the standardized NaOH, and the titration was measured by the pH meter.
The was repeated for 2-3 good samples of each coffee brand
A spiked sample of Folders coffee was spiked with ___ .1M HCl and tested as a control group
11. Data
15. Starbucks
18. Conclusion The spiked sample was similar to the titration curves of the samples in both procedures, which indicated that the experiment was performed correctly. This also means that if was effective.
Folgers had an average acidity of 0.03589M
Dunkin Donuts had an average acidity of 0.03181M
Starbucks had an average acidity of 0.03703M
Starbucks was the most acidic out of the three brands tested.
19. Soluble Solids
20. Background The strength of the coffee and its percent of soluble solids are the same.
Soluble solids are the materials extracted from the ground coffee by hot water.
The main soluble solids contribute to taste, aroma, strength, and color.
21. Procedure part 2 Main Method:
Two samples of each Brand (Starbucks, DunkinDonuts, and Folgers) were boiled into 40mL of water. These samples were filtered and the filtrate was dried in the oven overnight . The products were weighed to determine percent yield.
Spiked sample
A sample of DunkinDonuts coffee was mixed with a known amount of salt (which is a soluble solid and therefore will follow the procedure correctly) and the method above was used.
22. Data
23. Conclusion The spiked sample shows that our procedure was effective.
Dunkin Donuts had an average percent soluble solids of 14.22%.
Starbucks gave an average percent of 24.383%.
Folgers had an average percent of 13.0286%.
Therefore, Starbucks has the most soluble solids.