If shots are extracting too slowly, what adjustment should be made?

When shots of espresso are extracting too slowly, the primary adjustment should be to make the grind coarser. The grind size of the coffee directly impacts the flow rate of water during extraction. If the coffee is ground too fine, it can create excessive resistance for the water, slowing down the extraction process. By coarsening the grind, the coffee particles create more space for water to flow through, leading to a faster extraction time, which helps achieve the desired flavor profile and consistency for espresso shots.

Adjustments like increasing water temperature or using less coffee do not directly address the resistance caused by fine grounds. Additionally, making the grind finer would only exacerbate the slow extraction issue. Coarsening the grind is the most effective solution to rectify the flow rate of the espresso, ensuring optimal flavor extraction and overall beverage quality.