Cotter et al. Consumer preferences for black coffee are spread over a wide range of brew strengths and extraction yields. J Food Sci. 2021;86(1):194-20. https://ift.onlinelibrary.wiley.com/doi/abs/10.1111/1750-3841.15561

Coffee brewing is both an art and a science, with factors like water temperature, extraction yield, and strength influencing the taste experience. This blog post delves into the study by Cotter et al., published in the Journal of Food Science in 2020, which investigates the preferences of black coffee drinkers, exploring how varied brew strengths and extraction yields impact consumer enjoyment.

Overview of the Study

The study aimed to understand the diversity in black coffee preferences among consumers. Using the well-known Coffee Brewing Control Chart (BCC), Cotter and colleagues examined how variables such as Total Dissolved Solids (TDS) and Percent Extraction (PE) interact to influence consumer preferences. The BCC traditionally offers a guideline for optimal flavour balance, suggesting an "ideal" coffee with a TDS between 1.15% - 1.35% and a PE of 18% - 22%. However, the researchers sought to explore if these "ideal" conditions genuinely reflect consumer preferences.

Methodology

The study employed a comprehensive 3 × 3 × 3 factorial design, manipulating three main factors: Brewing Temperature (BT), TDS, and PE, each at low, medium, and high levels. A cohort of 118 participants, primarily young adults, sampled 27 coffee variations based on these factors. Participants rated coffee samples for temperature, flavour intensity, acidity, and mouthfeel, using standard hedonic and "Just About Right" scales. Additionally, they described the coffee using 17 flavour descriptors.

To ensure consistency in extraction rates across the different temperatures, the study adjusted grind size, brew ratio, and brew time, maintaining a balanced representation of all factors. This rigorous approach enabled the researchers to precisely identify how changes in each variable affected the coffee's taste profile.

Key Findings

1. General Preference Trends:

   • Across all participants, the study found a moderate preference for low-to-medium TDS over high TDS coffees, with a slight leaning toward medium-to-high PE.

   • The highest average consumer liking scores aligned with the traditional BCC “ideal” range, suggesting some basis in consumer preference for the industry-standard extraction profile.

2. Significant Individual Variability:

   • The results revealed notable individual variability in coffee preferences, particularly related to TDS, indicating that not all coffee drinkers prefer the same strength. While TDS emerged as the most influential factor, some participants preferred high or low extremes.

   • Segmenting consumers into clusters showed two distinct groups based on TDS preference: Cluster 1 preferred medium and high TDS coffees, while Cluster 2 favoured lower TDS coffee.

3. Preference Clusters and Sensory Profiles:

   • The study’s clustering analysis unearthed two main consumer segments. Cluster 1’s members, who preferred higher TDS, enjoyed complex flavour notes such as sweet, fruity, and citrus at low PE, or bitter and roasted profiles at high PE. This suggests they favoured “extreme” flavour profiles with prominent sensory characteristics.

   • Cluster 2 preferred a gentler flavour profile, aligned with lower TDS levels, often described as “sweeter” and “balanced.” This group’s preferences were less influenced by brewing temperature, as long as the other factors yielded similar extraction profiles.

4. Reevaluating the Brewing Control Chart:

   • Cotter et al. proposed that the traditional BCC “ideal” may need revision to accommodate segmented consumer preferences. The current ideal range might not align with the preferences of all consumer groups, particularly those attracted to more distinctive flavour characteristics at different TDS and PE combinations.

Discussion and Implications

This study underscores the variability in consumer preferences, suggesting that while the BCC’s “ideal” coffee profile holds some relevance, it may not fully satisfy the diverse palate of black coffee drinkers. By identifying two preference clusters, Cotter et al. illustrate that consumer tastes span a broader spectrum, with distinct groups showing preference for different brewing strengths.

The implications for coffee professionals are significant. While industry standards like the "Gold Cup Standard" provide a useful benchmark, this study suggests that consumer preferences are more nuanced, and baristas, roasters, and coffee brands may benefit from tailoring their offerings to suit both traditional preferences and more unique flavour profiles. In an increasingly personalized market, recognising and catering to these taste distinctions could enhance consumer satisfaction and loyalty.