Current Challenges of Cold Brew Coffee—Roasting, Extraction, Flavor Profile, Contamination, and Food Safety

Abstract

Cold brew coffee has emerged as a new trend over the last decade. However, “cold brew” is an extraction style of ground roasted coffee with water at lower than body temperature (typically 8 °C or room temperature), rather than a beverage per se. Cold brew extraction poses several challenges, including the need for specific optimization depending on the multiple influences of coffee variety and processing, roast degree, grinding, dosage, water composition, turbulence, brew system (drip, immersion etc.), time and temperature, and their interactions. While cold brew is typically characterized by a floral sweetness, over-extraction may lead to abundant acidity and bitterness. To avoid this, an extraction degree of 70% was suggested using shorter time frames (i.e., 2 h at 15 °C with 80 g/L coffee for optimized medium roast profiles). Due to the lack of sterilizing temperatures during preparation, cold brew is significant in the coffee sector because hygiene and food safety requirements pose specific challenges. To avoid microbiological contamination and deterioration in quality, cold brew should be as freshly prepared as possible and shelf-life should be minimized.

Ultrafast extraction of cold brew coffee in a planetary rotating bed reactor: A kinetic study on the pushback effect

“…Still, the long process times of the prevalent static immersion methodology, ranging from several hours to days (Pospisil, 2023;Fuller & Rao, 2017), can be uneconomic in industrial settings and impractical in household and coffeehouse production. Besides techno-economic constraints, the long process times entail additional hygienic and sterility requirements (Kwok et al, 2020;Lachenmeier et al, 2021), as well as the risk of over-extraction of certain compounds and therefore, sensory offflavors (Cordoba et al, 2019;Morresi et al, 2021). The separation of spent coffee grounds after extraction is a further constraining aspect given some coffee-specific conditions (Bühler et al, 2023).…”

“…These need to be addressed to increase process efficiency while ensuring product quality. This concerns reducing process time, minimizing the need for postextraction filtration, preventing over‐extraction (bitter taste), and maximizing the product and extraction yield (EY) (Cordoba et al, 2019; Kwok et al, 2020).…”

Towards the Smart Industry for the Sustainability through Open Innovation based on ITSM (Information Technology Service Management)

“…In fact, coffee is the second largest commodity after oil and the second most popular beverage after water, and most coffee product manufacturers face high prices for imported raw materials and energy, which is a major factor [56]. Production processes such as extraction and drying are both energy intensity and environmental issues from many studies that have been identified to improve the quality of the flavor and other attribute within the coffee [57], [58].…”

Use of sensors for mathematical modeling during the roasting of cocoa beans (Theobroma cacao) of the Chuncho variety

“…Se ha monitoreado la temperatura del centro de granos de café mediante termocuplas tipo K inseridas en el centro en un tostador rotatorio (Fabbri et al, 2011). Hay varias investigaciones, sobre el efecto en el incremento de fenoles y flavonoides en leguminosas (Hong et al, 2020), en el trigo sarraceno (Ryu et al, 2020), en granos de café (Kwok et al, 2020;Münchow et al, 2020), en la calidad de chocolate (Edem et al, 2016;Fernández-Romero et al, 2020;Kadow et al, 2015), entre otros alimentos (Ciou et al, 2021;Górecki & Hallmann, 2020;Hong et al, 2020;Rabeler & Feyissa, 2018). El análisis de la transferencia de calor con ayuda de sensores de temperatura, es una herramienta valiosa para monitorear o predecir las temperaturas del grano durante el tostado.…”

“…Al contrario, la temperatura del aire se incrementa durante 1 minuto y cae ligeramente por la absorción de calor por los granos. Comportamiento semejante a la temperatura de los granos fue observada durante el tostado de granos de café en tostador artesanal israelí (Kwok et al, 2020).…”