Coffee Science Foundation investigates where the sweetness in coffee comes from

Coffee Science Foundation

The Coffee Science Foundation is launching a new research project to determine where the sweetness in coffee really comes from.

According to the Coffee Science Foundation (CSF), many specialty coffee consumers and experts agree that a key part of coffee quality is the natural sweetness in coffee flavour.

However, CSF Executive Director Peter Giuliano says a recent research paper titled Sensory and monosaccharide analysis of drip brew coffee fractions versus brewing time, published by the Journal of the Science of Food and Agriculture, has confirmed that the sweetness in coffee does not come from sugars in the bean.

“The research paper states, ‘the mass spectrometry measurements firmly established that the total concentration of all the sugars present, in any fraction, was well below the sensory perception threshold for sugars, meaning that human tasters are not capable of perceiving the sugar in the coffee we tested’,” says Giuliano.

“It is not an exaggeration to say that the specialty coffee industry is built on flavour. [The fact] that the cause of a major coffee flavour is unknown is a big gap in our knowledge. The Coffee Science Foundation is dedicated to filling these knowledge gaps with high-quality research, for the benefit of the whole industry.”

As such, the CSF is conducting its own sweetness research project, ‘Sweetness in Coffee: Sensory Analysis and Identification of Key Compounds’, with the aim to help plant breeders, cuppers, roasters, and farmers produce higher quality coffees. Giuliano hopes it will improve tools for the industry, such as better cupping forms and roasting devices.

“We hope to develop improved ways of training cuppers to detect sweetness, and furthermore help agronomists and plant breeders develop better techniques and materials for the specialty coffee industry,” Giuliano says.

“More than anything, I hope that this research helps us create higher-value coffees at the agricultural level, so coffee producers can benefit from advances in coffee science.”

The project began in December 2022 in collaboration with the Specialty Coffee Association (SCA) and Flavor Research and Education Center (FREC) in the College of Food, Agricultural, and Environmental Sciences (CFAES) at The Ohio State University in Columbus, Ohio.

According to Giuliano, the FREC has developed “untargeted” chemical fingerprinting methods to advance the understanding of stimuli that contribute to flavour, termed flavouromics. These methods are well suited to define complex flavour perceptions, such as sweetness, that can originate from multiple sensory systems such as smell (olfactory) and taste (gustatory), or by flavour modulators.

“We are excited to apply these new methods of flavour discovery in collaboration with the FREC to improve our understanding of this key attribute of coffee quality,” says Giuliano.

“Just a glimpse at FREC’s recent project list, such as understanding the source of bitterness in wheat bread or the flavour of hazelnuts, makes it clear that they have a unique set of tools and insights to help with this investigation. Specifically, they have a state-of-the-art chemical laboratory and sensory panellists, which are key to this research.”

The SCA provides key support for the CSF, as well as serving as a platform for research dissemination and education for a variety of topics.

Simonelli Group also provided an unrestricted grant to the CSF which helped support this research.

Research results are expected in late 2023. In the meantime, Giuliano has his own theory on coffee sweetness, which suggests ‘cross-modal perceptions’, that involves interactions between two or more different sensory modalities, may be the cause of sweetness associated with sugars in coffee beans.

“Over the years, I’ve learned a lot about ‘cross- modal perceptions’ and it could be a combination of a cross-modal effect and some new chemical. Or it could be something completely different, I can’t wait to find out,” Giuliano says.

This article was first published in the March/April 2023 edition of Global Coffee Report. Read more HERE.

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