Precision Brewer

September 20,2024

Precision Brewer

In-depth coffee brewing research reveals the influence different variables have on flavour. Explore the six sensory factors in more detail and how they guide you to your perfect tasting coffee.

Perhaps unsurprisingly, the most important factor influencing taste was the roast level of the coffee beans. Before roasting, coffee beans are green with little or no taste. Roasting develops different aroma compounds, and the length of the roast affects these compounds and determines the flavour. Many people choose a medium roast, but it’s worth exploring both lighter and darker roasts to get a greater appreciation for different flavours, and learn which roast suits you.

This factor might surprise you, but the shape of the basket has a greater impact on flavour than most other variables. By simply swapping out the filter basket, you can dramatically transform the flavour of the brew. The experts found that certain flavours are associated with different basket shapes, so you can choose a basket for brewing that matches your flavour preferences.

This is the ratio of ground coffee to water used to brew, and it makes sense that varying the ratios will affect the flavour of your coffee. Most baristas would use brew ratios of between 1:15 and 1:18, which means for every gram of ground coffee they are adding between 15 grams to 18 grams of water.

Grinding coffee beans increases the surface area of the coffee that comes into contact with the water, and how coarse or fine the grind is determines how quickly water can pass through it. In turn, this influences how your final brew tastes. Your personal taste preference will determine the ideal grind size.

The length of time the coffee stays in contact with the water affects the level of extraction, which is the process of drawing the flavour compounds from roasted and ground coffee. These compounds are not all extracted at the same time. First up are the fruity and acidic notes, followed by sweetness and balance, and lastly bitterness. As a result, the brew time produces different coffee flavours.

During extraction, water draws the flavour from the coffee grounds. The temperature of the water is an essential part of the process because if the water is too hot you risk an over extraction, resulting in a bitter tasting coffee, and if the water is too cold, under extraction may occur leaving a weaker, sour-tasting coffee. As part of the research, we found within our temperature testing range of 188-200°F (87-93°C) there wasn’t a significant flavour difference, but coffee connoisseurs might appreciate the flavour subtleties.