Adia Sisson

IB Chemistry: pH of Coffee With Respect to Brewing Time

In my second year of IB Chemistry, we were given an open assignment of designing a lab answering a research question of our creation based on the topics covered in the two-year class. I chose to study the effect of extraction time on the concentration of hydrogen ions in coffee. The results of my study did not meet my expectations, as the brewing times were all too long to get an accurate picture of the change in concentration, showing the pH after the coffee had been almost fully extracted. Rather than showing a steady increase in pH, the results showed the flattened portion of the exponential graph meeting almost exactly with the horizontal asymptote.