To determine the combined effects of pH and temperature on browning rates, catechol and Pi buffer were held at fixed final concentrations of 15.6 mM and 50 mM, respectively, while the pH was varied in increments of 0.2 units between 7.0 and 8.0. Three temperatures were assessed, in triplicate: a dry block incubator was set to 37 °C, room temperature was confirmed to be 25 °C (with constant monitoring), and a laboratory refrigerator was confirmed to be 4 °C. Aliquots of deionized water, Pi buffer, and catechol solution were pre-incubated to the desired temperatures before mixing. Reaction mixtures of 1,800 L were prepared in 2-mL microtubes, and reactions were initiated with the addition of catechol. A 200 L aliquot was immediately withdrawn and distributed to a microplate well, with absorbance at 340 nm recorded. Microtubes were returned to the dry block incubator, laboratory bench, or refrigerator for continued incubations. Further 200 L aliquots were withdrawn at 60-min intervals for 6 h. Rates of browning were calculated as the change in absorbance at 340 nm over time.