Tropentag, September 11 - 13, 2024, Vienna "Explore opportunities... for managing natural resources and a better life for all"

Peaberry coffee beans shape influence final cup quality

¹National Coffee Research Center of Colombia, Colombia
²EAFIT University, School of Applied Sciences and Engineering, Colombia

Abstract

It was traditionally considered that coffee peaberries were a defect in the coffee production process. There are usually two plano-convex seeds inside the berry; however, a single ellipsoidal seed may form for biological reasons: the peaberry. Due to this mutation, the peaberries were long considered a defect; further, their export was banned in many coffee-producing countries due to their significantly reduced shape and the worldwide demand for supreme beans. However, different sensory evaluations have revealed that the peaberry has a high cup quality. It is hypothesised that the bean shape accounts for these results. The roasting process occurs homogeneously throughout the bean's domain, and its shape makes it easy for it to roll inside the roaster enclosure. Nevertheless, the data shared in the literature regarding this topic are relatively scarce. Therefore, this study aimed to perform a set of image analyses on 3 samples of coffee beans (Coffea arabica L): 120 g of standard grain, 120 g of peaberries and a mixture of 60 g of standard and 60 g of peaberries. The samples were then medium roasted at the same temperature and conditions to better observe the tonality and roast uniformity in 100 randomly selected beans from each sample, from which 50 were cut transversely and 50 longitudinally. Afterwards, a high-resolution picture was taken with a stereoscope, normally located on the flat face. The pictures were processed through image analysis to identify colour mapping, intensity, discontinuities and anomalies in all the grains. The tonality was less variable in both individual and mixed samples of peaberries. Standard berries displayed anomalies in their inner structure generated during the roasting process in both individual and mixed samples. During the roasting process, air chambers formed inside the bean, which resulted in heat accumulation and overroasting, resulting in undesirable flavours and reducing the cup profile and quality.

Keywords: Coffee bean, image analysis, peaberry, roasting

Contact Address: Eduardo Duque-Dussan, National Coffee Research Center of Colombia, km 4 vía Chinchiná-Manizales, Manizales, Colombia, e-mail: eduardo.duquecafedecolombia.com