Research conducted by the Penn State Sensory Evaluation Centre showed a relationship between roasting levels and bitterness in chocolate. Specifically, using a more intense roast profile appears to reduce levels of bitterness, according to the researchers.

The challenge currently facing chocolate companies is in satisfying people’s sweet tooth with less sugar as consumers become more health-conscious. Typically, companies are looking towards sugar alternatives, but this has often affected the flavour in an undesirable way.

Helene Hopfer, Rasmussen Career Development Professor in Food Science in the College of Agricultural Sciences, comments:

More and more people these days are eating darker chocolates with less sugar and more cacao because they are trying to cut down on sugar intake or they want to take advantage of perceived health benefits.

There is typically a consequence that big chocolate companies have to consider when increasing the cocoa content and accordingly, decreasing levels of sugar. By using lower quality cocoa, the bitterness of the chocolate is intensified, which reduces its appeal to consumers who want chocolate to be a sweet snack.

Then there is the cost implication, as cocoa can be the most expensive input into the overall cost of the product, so companies tend to prefer adding cheap ingredients. However, this is a challenge that companies may have to overcome as consumers become more savvy and conscientious in their purchasing choices.

The goal of this new study was to determine the relationship between roasting cocoa beans and the taste of the final product. The findings confirmed that consumers disliked bitterness in chocolate, but also demonstrated that these undesirable qualities could be reduced by fine-tuning the roasting process.

Our research was intended to learn about bitterness perception and the liking of chocolate made from cacao roasted with a variety of roasting profiles to see if wide consumer acceptability of 100% chocolate is possible.

Helene Hopfer

The study looked at consumer perception of bitterness from a sensory evaluation standpoint, looking to quantify this information. In this sense, it differs from past studies that focused on bitter compounds found in cocoa beans, according to Hopfer.

The participants found the unsweetened chocolate most enjoyable when the cocoa beans were roasted for 20 minutes at 340 degrees Fahrenheit, 80 min at 275 Fahrenheit, and 54 min at 304 Fahrenheit.

Partnering with Penn State for this study was Alan McClure, the founder of Patric Chocolate and related consultancy Patric Food & Beverage Development. McClure sourced cocoa beans from three different locations: Madagascar, Ghana and Peru, and used his facilities in Columbia, Missouri to roast and grind the beans into a cocoa liquor which was then shipped to Penn State as solidified 100% chocolate.

The study involved 145 people tasting 27 different samples of 100% chocolate over five consecutive days. Each sample was roasted at a different intensity and prepared as a small chocolate disk for participants to consume. The findings, published in Current Research in Food Science, indicated that consumers’ acceptance of unsweetened chocolate was directly tied to the intensity of the roast.

As an example, the participants found the unsweetened chocolate most enjoyable when the cocoa beans were roasted for 20 minutes at 340 degrees Fahrenheit, 80 min at 275 Fahrenheit, and 54 min at 304 Fahrenheit.

100% chocolate produced from lightly roasted cacao, such as those roasted for 11 minutes at 221 Fahrenheit, or 55 minutes at 147 Fahrenheit, were deemed unacceptable, however.

McClure says these findings will guide him and roasters at chocolate manufacturing companies going forward. He stated that when it comes to producing 100% chocolate, there isn’t much that chocolate makers can do, [once they are in possession of the beans], to influence the flavour of the final product, other than vary their approach to the roasting. “Our results show optimal roasting can adequately reduce bitterness”, concludes Hopfer.

Continuing to study every aspect of chocolate production from bean to bar will hopefully produce new innovations in chocolate production and answers to some of the challenges raised by evolving consumer trends.

These findings may not come as a surprise to bean to bar chocolate makers who have been roasting for years, but it starts to establish data points about the effect of roasting on sweetness. This will be useful in applying science to quantify the approach, remove the trial and error and get more predictable results.

Photo by Jason Leung on Unsplash

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