Cold Brew Coffee – Pilot Studies on Definition, Extraction, Consumer Preference, Chemical Characterization and Microbiological Hazards

Abstract

Cold brew coffee is a new trend in coffee industry. This paper presents pilot studies into several aspect of this beverage. Using an online survey, the current practices of cold brew coffee preparation were investigated identifying a rather large variability with a preference for extraction of medium roasted Arabica coffee using 50-100 g/l at 8°C for about 1 day. Sensory testing using ranking and triangle tests showed that cold brew may be preferred over iced coffee (cooled down hot extracted coffee). Extraction experiments at different conditions combined with nuclear magnetic resonance (NMR) analysis showed that the usual extraction time may be longer than necessary as most compounds are extracted within only a few hours, while increasing turbulence (e.g. using ultrasonication) and temperature may additional increase the speed of extraction. NMR analysis also revealed a possible chemical differentiation between cold brew and hot brew using multivariate data analysis. Decreased extraction time and reduced storage times could be beneficial for cold brew product quality as microbiological analysis of commercial samples detected samples with spoilage organisms and contamination with Bacillus cereus.

Review on factors affecting coffee volatiles: from seed to cup

“…Most extraction methods use hot water to extract coffee, but cold extractiona new method including immersion and dripping, using cold water during the extraction processhas recently been very well received around the world. 92,93 According to market analysis, the market value of cold-brew coffee was US $321 million in 2017 and is expected to reach US $1.37 billion by 2023. 94 Cold-brew coffee is made by the extraction of water at 20-25 °C or lower temperatures, and over a longer period that can vary from 8 to 24 h. Some furans, pyrazines, ketones, aldehydes, pyrroles, esters, lactones, furanones and phenols were identified in cold-brew coffee prepared at 19 °C with specialty coffee from Colombia.…”

“…Most extraction methods use hot water to extract coffee, but cold extraction – a new method including immersion and dripping, using cold water during the extraction process – has recently been very well received around the world 92,93 . According to market analysis, the market value of cold‐brew coffee was US $321 million in 2017 and is expected to reach US $1.37 billion by 2023 94 .…”