Optimization of Cold Brew Coffee Using Central Composite Design and Its Properties Compared with Hot Brew Coffee

Area of Science:

• Food Science
• Beverage Chemistry
• Sensory Analysis

Background:

• The global popularity of cold brew coffee (CBC) is rising, yet scientific literature remains limited, especially regarding its health benefits compared to hot brewed coffee.
• Existing research often focuses on green coffee beans or hot water extraction methods, leaving the properties of CBC under-explored.

Purpose of the Study:

• To investigate how brewing conditions influence the physicochemical properties of cold brew coffee.
• To optimize cold brew coffee brewing parameters using response surface methodology.
• To compare the resulting cold brew coffee with coffee brewed using the French Press method.

Main Methods:

• Response surface methodology with Central Composite Design was employed to assess the impact of brewing variables (water temperature, coffee-to-water ratio (C2WR), coffee mesh size, extraction time) on total dissolved solids (TDS).
• Physicochemical properties, antioxidant activity, volatile compounds, and organic acids were analyzed and compared between cold brew coffee and French Press coffee.
• Optimized brewing conditions were determined for cold brew coffee.

Main Results:

• Water temperature, C2WR, and coffee mesh size significantly affected the TDS of cold brew coffee.
• Optimized brewing parameters were identified as 4°C water temperature, a 1:14 C2WR, 0.71 mm coffee mesh size, and 24-hour extraction time.
• At comparable TDS levels, cold brew coffee exhibited higher caffeine content, volatile compounds, and organic acids than French Press coffee.

Conclusions:

• Cold brew coffee shares many characteristics with hot brew coffee at similar TDS levels.
• Key differences include higher caffeine and sensory-related compound content in cold brew coffee.
• The developed model for TDS prediction can assist the food industry in optimizing cold brew coffee production for desired characteristics.