Drip brewed coffee is traditionally quantified in terms of its strength, also known as total dissolved solids (TDS), and its brewing yield, also known as percent extraction (PE). Early work in the 1950s yielded classifications of certain regimes of TDS and PE as "underdeveloped," "bitter," or "ideal," with the modifiers "weak" or "strong" simply correlated with TDS. Although this standard is still widely used today, it omits a rich variety of sensory attributes perceptible in coffee. In this work, we used response surface methodology to evaluate the influence of TDS and PE on the sensory profile of drip brewed coffee. A representative wet-washed Arabica coffee was roasted to three different levels (light, medium, or dark), with each roast then brewed to nine target brews that varied systematically by TDS and PE. Descriptive analysis found that 21 of the 30 evaluated attributes differed significantly across the brews for one or more experimental factors, yielding linear or second-order response surfaces versus TDS and PE. Seven attributes exhibited a significant response surface for all three roast levels tested: burnt wood/ash flavor, citrus flavor, sourness, bitterness, sweetness, thickness, and flavor persistence. An additional seven attributes also showed a significant response surface fit across some but not all roasts. Importantly, sweetness exhibited an inverse correlation with TDS irrespective of roast, while dark chocolate flavor and blueberry flavor decreased with TDS for medium roast. These results provide new insight on how to optimize brewing conditions to achieve desired sensory profiles in drip brewed coffee. PRACTICAL APPLICATION: This research provides guidance on how best to achieve specific flavor profiles in drip brewed coffee.

中文翻译：

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冲泡强度、冲泡产量和烘焙度对滴滤咖啡感官品质的影响

传统上，滴滤咖啡是根据其强度（也称为总溶解固体 (TDS)）和其酿造产量（也称为提取百分比 (PE)）来量化的。1950 年代的早期工作将 TDS 和 PE 的某些制度分类为“不发达”、“苦味”或“理想”，修饰语“弱”或“强”与 TDS 简单相关。尽管该标准今天仍被广泛使用，但它忽略了咖啡中可感知的丰富多样的感官属性。在这项工作中，我们使用响应面方法来评估 TDS 和 PE 对滴滤咖啡感官特征的影响。典型的湿洗阿拉比卡咖啡被烘焙到三个不同的级别（浅、中或深），每次烘焙然后酿造九个目标酿造，这些酿造根据 TDS 和 PE 系统地变化。描述性分析发现，对于一个或多个实验因素，30 个评估属性中的 21 个在酿造过程中存在显着差异，与 TDS 和 PE 相比，产生线性或二阶响应面。七个属性对所有三个测试的烘焙水平都表现出显着的响应面：烧焦的木头/灰烬味、柑橘味、酸味、苦味、甜味、浓稠度和风味持久性。另外七个属性也显示出在一些但不是所有烘焙中的显着响应面拟合。重要的是，甜度与 TDS 呈负相关，与烘焙无关，而黑巧克力风味和蓝莓风味随中度烘焙的 TDS 降低。这些结果为如何优化冲泡条件以在滴滤咖啡中实现所需的感官特征提供了新的见解。实际应用：这项研究提供了有关如何最好地在滴滤咖啡中实现特定风味特征的指导。