Acidity is a highly prized attribute in coffee, but there is little understanding of the brewing conditions under which acidity contributes favorable sensory attributes versus unfavorable sourness. Here, we examine the effect of titratable acidity and pH on the perception of sourness and consumer acceptance in drip brew coffee. Sour perception and acidity liking were assessed over a wide range of brew strengths and extraction yields at three different roast levels (light, medium, dark) and three different brewing temperatures (87 °C, 90 °C, and 93 °C). We find that perceived sour intensity correlates weakly with pH, but strongly with titratable acidity. Increases in titratable acidity also yielded increases in consumer perception of “too much acidity” and also impacted consumer liking and consumer preference segmentation with one cluster of consumers preferring more acidic coffee. Importantly, our data show that titratable acidity is linearly correlated with total dissolved solids (TDS) under all conditions studied, indicating that TDS is a good proxy for titratable acidity. The results presented here will provide the coffee industry with insight toward controlling perceived acidity or sourness, a key sensory attribute that substantially impacts consumer acceptance.

中文翻译：

---

滴煮咖啡的可滴定酸度，感知酸度和酸度

酸度是咖啡中极受重视的属性，但对酿造条件的了解很少，在这种条件下，酸度有利于感官特性，而不利于酸味。在这里，我们研究了滴定咖啡中可滴定的酸度和pH值对酸味和消费者接受度的影响。在三种不同的烘烤水平（浅色，中度，深色）和三种不同的酿造温度（87°C，90°C和93°C）下，在广泛的酿造强度和提取产量下评估了酸味和酸度。我们发现，感知到的酸味强度与pH弱相关，但与可滴定酸度密切相关。可滴定酸度的增加也使消费者对“太多酸度”的认识增加，并且还影响了消费者的喜好和消费者偏好细分，其中一类消费者更喜欢酸性咖啡。重要的是，我们的数据表明，在所有研究的条件下，可滴定酸度与总溶解固体（TDS）呈线性关系，表明TDS是可滴定酸度的良好替代。此处提供的结果将为咖啡行业提供有关控制感知到的酸度或酸度的见识，酸度或酸度是一种关键的感官属性，会严重影响消费者的接受程度。