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Conestoga High School Berwyn, PA 19312 Jennifer L. Castor, Ryan C. Henrici, Samantha W. Webster A multivariable approach to maximizing caffeine content in coffee

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Average American drank 416 8 ounce cups coffee in 2009 Problem Caffeine acts as a psycho-stimulant: increases awareness and focus Average caffeine consumption is less than 300mg per day Why do we need this to get our caffeine? http://flowingdata.com/wp-content/uploads/2011/01/Starbucks-trenta-575x654.jpg

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Prior Research in Coffee Chemistry

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H igh P erformance L iquid C hromatography Overview: HPLC separates and quantifies the constituents of a solution Separation : column separates constituents based on polarity , in our case the polar caffeine molecule was most highly attracted to the column walls and therefore retained the longest . Quantification : occurs when separated constituents are exposed to light in detector, their absorbances can be used to determine their concentrations . Cart Mounted System High Pressure Pump Column What does HPLC do?

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Apparatus "Coffee Percolators." Coffee Maker Reviews | Best Coffee Makers | Single Cup Coffee Makers . Web. 15 Mar. 2011. <http://www.find-your-next-coffee-maker.com/coffee-percolators.html>. Percolation Coffee Maker Experimental Apparatus

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Procedure ** Standards used: 0100g/100mL, .0250g/100mL, .0500g/100mL, .1000g/100mL, .1500g/100mL

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Brew Time Brew Temperature Grain Type Amount of Grains brewed pH of brewing water Coarseness of grains Brand of Grains Variables involved in Brewing Process Brew Temperature Brew Time Amount of Grains brewed Brand of Grains Variables Analyzed

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Brew Temperature Study Control Group: Brewed at 80°C Experimental Groups: Brewing at 30°C Brewing at 50°C Brewing at 70°C Brewing at 90°C Brewing at 95°C Brewing at 100°C Brewing Constants : Brew Time = 1 minute Grain Type: Folgers Classic Medium Roast 1.46g-grains/50mL-water Apparatus Filter Type: Bunn Coffee Filters Brew Method Injection Temperature

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Correlation between brewing temperature and caffeine concentration was found to exist!

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Brew Time Study Control Group: 60 Second Brew Experimental Groups: 10 Second Brew 80 Second Brew 140 Second Brew 200 Second Brew 260 Second Brew 320 Second Brew 620 Second Brew Brewing Constants : Brew Temperature: 80°C Grain Type: Folgers Classic Medium Roast 1.46g-grains/50mL-water Apparatus Filter Type: Bunn Coffee Filters Brew Method Injection Temperature

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Brewing longer may not mean significantly more caffeine +45.6mg in 200sec +9 mg in additional 360sec

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Amount of Grounds Study Control Group: Brewing with 1.46g Experimental Groups: Brewing with 0.73g (50%) Brewing with 1.095g (75%) Brewing with 1.825g (125%) Brewing with 2.19g (150%) Brewing with 2.92g (200%) Brewing with 4.38g (300%) Experimental Constants: Brew Time = 1 minute Grain Type: Folgers Classic Medium Roast Brewing at 80°C Apparatus Filter Type: Bunn Coffee Filters Brew Method Injection Temperature

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Brewing more grains yields more caffeinated final cup

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Coffee Brand Study Control Group: Folgers Medium Roast Experimental Groups: Wegmans Exotic Day Break Roast Starbucks Pike Place Roast Eight O’Clock Medium Roast Peet’s House Blend Maxwell House Medium Roast Dunkin’ Donuts Medium Roast Experimental Constants: Brew Time = 1 minute 1.46g-grains/50mL-water Brewing at 80°C Apparatus Filter Type: Bunn Coffee Filters Brew Method Injection Temperature

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America’s favorite is more caffeinated than Starbucks or Dunkin’ Donuts

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Conclusion Brewing hotter yields more caffeine Brewing Temp can be controlled in certain methods: French Press Coffee Singles Brewing hotter may also make a stronger tasting drink Consumers may still opt for higher volume to preserve the taste

Conclusions:

Conclusions The amount of caffeine for each of the 35 samples plotted versus their brew times yields a correlation that is best described using a power model with the equation: y = 67.501x 0.1233 This relationship has an R² value of 0.8833 Comparisons between the amount of caffeine in a 10 second brew sample and an 80 second brew sample suggest that the majority of the caffeine in coffee is dissolved into the solution in the first few seconds of brewing.