Since the flavor of espresso is very concentrated, flavor imperfections are a lot more noticeable than in other types of coffee. For this reason, having high quality coffee beans that are grown under the right conditions, carefully harvested and processed, and roasted to perfection is especially important to achieve the best flavor possible. This combined with the fact that espresso has to be brewed with beans that are less than two or three weeks past roast date, makes the cost of beans higher. Combined with the cost of beans, espresso cannot be brewed in large batches and cannot be brewed ahead of time as espresso tastes best immediately after brewing. This means that to brew an espresso, it must be done one at a time, which takes time and time is money. If you make a milk-based drink with espresso, such as a latte, the milk has to be steamed just prior to the drink being consumed. This also means that additional time is needed for each and every drink. You cannot steam milk in large batches and have good results in terms of flavor. Due to the artisan nature of making espresso based drinks and the quality of the ingredients needed, the cost per drink is higher than other comparable drinks that can be batch produced.