GROUP 4 BIOLOGY Student: Teacher Supervisor:
PARINDA PRAPAIWONGS Ms. Ellen Clampitt
Does water really need to be boiled to 100 degree Celsius in order to make a good cup of tea?
ABSTRACT Generally, people usually overheat water from a kettle to make their cup of tea and leave the excess water to be reheated later. This action consequently causes the amount of carbon dioxide emission increasing daily. The aim of this essay is to examine and answer the research question that ‘Does water really need to be boiled to 100°C in order to make a good cup of tea?’ In this extended essay, the investigation consists of two experiments, measuring absorbance of tea and taste test, which were used to compare the quality of tea brewed in different temperature of water and analyze the answer for the research question. Two different type of tea were investigated, oolong tea and chamomile tea, with the same steeping time and temperature. The colorimeter showed the concentration of tea that the higher absorbance value means the more concentrated and better quality of tea meanwhile results deduced from the taste test were based on the participant’s tea preferences to distinguish the better taste of tea brewed at 90°C and 100°C. Conclusively, the results were indicative that the tea brewing temperature for a perfect brew depends on the type of tea as shown that oolong can be successfully brewed at 90°C with similar concentration and taste, unlike chamomile tea which needs more evidence to answer the research question. Further investigation is required to include other types of tea such as green, jasmine or chai, for example. This will help determine if they have similar results as brewing oolong tea.