Master of Science / Food Science Institute / Edgar Chambers, IV / A total of more than 100 different coffee samples from 14 countries around the world were used to create a coffee lexicon. The first list of terms consisted of 74 attributes that were developed from the review of 13 samples from Colombia. A second development incorporated an existing commercial lexicon and examined an additional of 72 coffee samples from different parts of the world. Validation sessions were also performed with 20 samples from the area of San Adolfo, Colombia. Principal Component Analysis (PCA) was used to mapped the scores obtained during the validation phase of the terminology, the panelists were able to described specific characteristics that were present in the coffee samples such as sweet, nutty and fruity notes, as well as the differentiation of notes such as burnt, smoky, astringent, acrid and bitter. At the end of the process, a total of 110 attributes and their references were identified. Another study was conducted to identify the sensory properties of three coffee samples using four different brewing methods. The coffee samples were prepared using a consumer drip coffee maker, a home or food service automated espresso machine, a coffee grader “cupping” method and a filtered infusion method. The cupping method produced a higher intensity for the “roasted” flavor attribute across all samples. This method also tended to produce higher scores for burnt and acrid than other brewing methods. Flavor and aroma attributes both varied with preparation methods, but not necessarily in the same ways. The drip brewing method showed the most differences in the three coffee samples for aroma, flavor and aftertaste attributes, but other methods may be appropriate depending on the objectives of each study.

Masters of Science / Department of Food, Nutrition, Dietetics and Health / Edgar Chambers IV / In today’s market, there is a growing demand for high-quality coffee with distinctive sensory characteristics. An example of such coffees is the cold brew which has become quite popular. Despite the increasing prevalence of cold drip/brewed coffee, little-published research exists on the factors that impact the sensory characteristics of cold brew coffee. The objectives of this study were to determine the impact of a) degree of roasting, b) coffee to water ratio (C2WR) and c) brewing methods on cold brew coffee from d) Ugandan coffee beans. Four distinct coffee samples, sourced from different lowland and mountainous regions in Uganda, were roasted and tested using a factorial design that allowed comparison of all main factors (a-d) and their interactions. The samples were evaluated by a highly trained sensory panel based on 42 attributes from a previously published coffee lexicon. Results showed that all aspects studied (Ugandan variety, roast degree, C2WR, and brewing method) had an impact on most of the attributes. For example, Robusta coffees generally had a more bitter taste than Arabica coffees and the Dark roast samples generally were more bitter than the Medium roast coffees. In addition, coffee samples that were brewed using a higher coffee to water ratio (C2WR) generally were more bitter than the coffees that were brewed using a lower C2WR. However, although most of the main effects had a significant impact, their effects were mitigated by their interaction with other factors. For example, Medium roast Robusta that was slow-dripped with a high C2WR had a more bitter taste than the corresponding Arabica samples however when the Medium roast Robusta was steeped with a high C2WR it had a similar bitter intensity with the corresponding Arabica samples. Thus, although major impacts are critical, individual sample combinations must be considered when evaluating coffee samples for their impact on the sensory characteristics.