What makes the perfect cup?
Over the last three years, we partnered with coffee experts at the Coffee Science Foundation, UC Davis Coffee Center and the Specialty Coffee Association to advance our understanding of coffee brewing. By sharing the results of this sensory research, brewing your perfect coffee has never been easier.
There are 6 factors that determine the taste of your brew
The research team identified six factors that had a sensory impact on the taste of your coffee.
Your perfect brew starts with 3 key factors
01. Roast Level
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.
Light brown in colour with no oil on the surface of the beans, light roasted coffee is commonly more acidic with fruity, bright flavours. A light roast retains the unique origin flavours of the beans to a greater degree.
A medium roast is brown in color and offers more body than light roasts. The coffee starts to approach the darker, caramel sweetness of a longer roast, and exhibits a more balanced flavour and aroma.
Dark brown in colour with a sheen of oil on the surface, a dark roast has low acidity, heavy body, and deeper, darker flavours. The origin flavour of the coffee is overtaken by the roasting flavours, with a taste that is bitter, smoky and earthy.
02. Filter shapes
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.
Flat bottom basket
Sweet, floral, dried fruit and chocolate flavours were emphasised with brewing in flat bottom baskets.
Bright, berry, citrus and fuller bodied brown roast notes were emphasised with brewing in semi-conical shaped baskets.
03. Brew ratio
The brew recipe 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.
The less coffee that is used, the increased perception of sweetness. The coffee will offer a more mellow and rounded taste with gentle acidity.
The brew ratio you decide upon will be guided by your personal taste preferences, but a ratio of 1:18 will deliver a rich and balanced flavour.
With more coffee used in the brewing process, the coffee will be more concentrated, with a rich, crisp taste and greater acidity.
Three factors for the Coffee Connoisseur
While the research shows that you can enjoy your perfect tasting cup by simply focusing on the first three key factors, for those coffee aficionados who like to dive deeper into the subtleties of flavour, the next three factors allow you to further refine the taste and create a brew that is exactly how you like it.
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.
A finer grind has the coffee packed closer together, so water takes longer to pass through, leading to greater extraction, more bitter flavours and a thicker body.
A coarser grind allows water to flow through the coffee more quickly, with a shorter brew time and less extraction, creating floral and dried fruit flavour notes.
05. Brew Time
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.
When the coffee is brewed for a shorter time, fruity, sweet, and spicy notes are emphasised, along with brightness, which coffee tasters refer to as acidity.
Coffee brewed for a longer time will have a fuller-bodied and thicker taste as the compounds that create sweetness and acidity will be overwhelmed.
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.
Ready to start enjoying your perfect brew today?
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