How to Adjust Your Coffee Brewing to Fit The Roast Level
January 21, 2021

How to Adjust Your Coffee Brewing to Fit The Roast Level

Brewing fresh coffee to achieve great flavour is a finely honed skill, with many variables. Every day we receive questions from Spiller & Tait customers and community members asking for advice on how to make the most of their preferred brewing method to achieve the perfect cup. Common questions include: the ideal settings on Bean-to-Cup machines; brewing times for cafetière; and how much coffee to use for the best espresso. We are very happy to answer these questions, as well as pointing people in the direction of our Brew Guides.

However, there is one factor which nobody has ever asked in relation to the coffee brewing process. And we ourselves have overlooked it in our published brewing tips or advice thus far. That is the need to adjust the coffee brewing process to match the roast level of your beans. This is a commonly over-looked factor, which will actually give you an edge in the coffee brewing stakes! For example, if you change your beans from a medium to a light roast, but follow the same brewing steps each time, you may not be getting the best from your beans.

The flavour and caffeine strength of roasted coffee beans are strongly influenced by the duration of the roasting process. This relates partly to the behaviour of the volatile aromatic compounds in coffee which give it aroma and flavour. The roasting process significantly increases the volume of these compounds, thus enhancing the flavour. However, as roasting periods lengthen, the flavour of the bean is overtaken by the taste of the roasting itself. In the typical roasting process, the fruity notes and acidity are developed first, followed by the sugars. It's a delicate process that, if not timed correctly, could lead to under-extracted sour beans or over-extracted bitter options!

You can find out more about the different levels of roasting and their impact on coffee flavour on our Different Roast Levels page. As a rule of thumb, light roasts hold more flavours of the coffee bean throughout the roasting process, leading to floral and citrus notes. Medium roasts are more chocolate and nut based in flavour, and dark roasts have the strongest smokey flavour! Medium and dark roasts are typically used to make short and sharp coffees, such as an espresso. While light roasts are for larger brews.

It’s also worth noting that lighter roasts are also less porous than darker ones, leading them to extract more slowly, so a slower brewing process is more ideal for these beans. The darker roasts, which are more porous, don’t taste as good in the slower brewing methods, like filter or cafetière, and this can lead to a more bitter taste, which most people prefer to avoid.

So, depending on the roast level of your beans, try the following adjustments in your brewing process to maximise flavour:

1. Grind Size

The finer the grind of your coffee beans, the more surface exposure to water and the more extraction of essential oils will occur. Usually finer grinds work better for the less porous lighter roast, and dark roasts work with coarser grinds. This is due to darker roasts being more bitter naturally, so they would need less contact time in the water to extract. Adjust the grind size depending on the level of your roast, finer for lighter roast. But, keep your grind close to the ideal grind size for your chosen brewing device.

2. Water Temperature

The hotter the water used in brewing, the stronger the extraction. Our recommended temperature range for brewing is between 90-96°C. Above 96°C and the coffee is in danger of burning. However, within this range, if you are making your coffee from darker roast beans we suggest you use a lower temperature for your water to help prevent the risk of over-extraction, which makes the coffee bitter. For a lighter roast, use the higher end of this temperature range to help speed up extraction. Many kettles and brew devices now give you the option of setting the desired water temperature to enable you to be precise.

3. Brewing Time

Our Brew Guides offer time ranges for brewing, otherwise known as steeping, depending on the brewing device and method being used. For example, pouring water more slowly when making filter coffee, or letting a French Press sit for longer before serving will produce better tasting coffee when using a light roast. A simple way to remember this is: the lighter the roast, the longer the steep, as this allows more flavours to develop.

We encourage you to keep these guidelines in mind when you're brewing at home. While we can’t guarantee a perfect cup of coffee, this tip to adjust your brew method to match the coffee roast level is one that very few people are aware of. So, you’ll have more chance of creating the perfect cup than many!