Comparison of espresso coffee brewing techniques

Several brewing techniques are used to make espresso coffee. Among them, the most widespread are bar machines and single-dose capsules, designed in large numbers because of their commercial popularity. As none of the current literature compares the effects of these different brewing techniques on espresso quality, this paper looks at two capsule methods and the traditional bar method. The methods were evaluated on the basis of the physico-chemical parameters and aromatic profile of nine espresso coffees prepared using the different techniques. Our results showed that with the same batch of roasted coffee, the same water and the same operative settings, the three different techniques can be distinguished by a principal component analysis. Furthermore, in terms of product reproducibility, the best results are provided by the two capsule systems.