S1: Episode 5: Exploring Roast Level And Its Impact On Your Coffee
This week’s episode delves into what is meant by roast level and the impact of roast level on brewing and coffee flavours. This week’s FACQ discusses the effect of roast level on the amount of caffeine in your coffee.
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Hello and welcome to The Coffee Drinker’s Guide, a podcast for the coffee curious where I explore and explain the world of specialty coffee to make your daily coffee better and more satisfying.
I’m Angela Holder a coffee roaster and writer on a mission to fight back against bad coffee by giving you the knowledge you need to help you get good coffee and a happier (coffee) life in coffee-break sized episodes. So grab your coffee, pull up a chair and take a break…
This week's episode is all about roast level. Light, medium, dark: what does it all mean? Get ready for a deep dive… and I’ll be answering an important question about dark roasts and caffeine levels at the end, so stay tuned for that….
Long before I worked in the coffee industry or even really knew much about coffee, there was one thing that I was sure of and that was that I didn’t like dark roast coffee. I found it too bitter and unpleasant to drink. It seemed like a punishment not a pleasure! However back then I was made to feel like I was unsophisticated for having this dislike of dark roasts and a preference instead for medium roast coffee. If only I’d known then what I am about to tell you now…
Firstly roast level and the brew
The big question is, does roast level affect coffee brewing? Yes, it does. Darker roasts are more porous and soluble than lighter roasts. This means that you can extract desirable flavours more quickly, which suits faster brewing methods like espresso. Lighter roasts are less soluble so need a finer grind and/or a longer brewing time for a good result: this is not so good for espresso and better suited to filter or cafetiere brewing methods. Additionally as covered way back in episode 1, for the best results, the temperature of the brewing water needs to be adjusted in relation to the roast level. Within the ideal brewing range of 88 to 92ºCelsius, or 190 to 198°Fahrenheit, cooler temperatures emphasise fruity and floral notes of lighter roasts, while hotter temperatures bring out the chocolate and nut flavours of darker ones, but also make the coffee more bitter. So you can take the edge off overly tart and fruity light to medium roast coffees by brewing at higher temperatures, or reduce bitterness in dark roasts by using cooler water.
Next roast level and the taste
The fundamental flavour of a coffee is a result of its terroir, which is how and where it's grown and processed into green, or raw, coffee beans. But the roast level can modify this flavour, sometimes strongly. The longer the beans are roasted, or cooked, the more the fruit flavour molecules in the coffee are broken down into sugars and caramelised. So light roasts are very floral, bright and fruity; medium roasts will have some fruity flavours but also more sweetness; and dark roasts will have a lot less fruit, but more heavy cooked sugar flavours like toffee, chocolate and nuts. Finding the sweet spot when it comes to a coffee’s ideal roast level is something that coffee roasters are constantly striving for and can be trickier to pinpoint than you may think. It is particularly easy to misjudge when to finish cooking a light roast. If it is under-roasted this results in under-cooked coffee that tastes mouth puckeringly grassy and sour. At the other extreme, a roast that is too dark may result in an acrid, ashy and bitter brew. Clearly neither of these do any favours for the coffee.
Finally roast level and the bean
Raw coffee beans are green in colour. As they are cooked, sugars in the beans caramelise and turn brown. Broadly, the longer they are cooked the darker brown they become, so the terms light, medium and dark refer to both the length of cooking time and the colour of the beans. Light roasts are cooked to the point where the coffee is just developed enough to taste everything that the coffee has to offer and look pale brown. Medium roasts are cooked a little longer to develop more of the sugars, and look mid brown or milk chocolate in colour. Dark roasts are cooked to the point where they may be a dark brown to nearly black in colour and often have an oily sheen on the surface of the beans. You should know that there are no official industry standards for what defines each level of roast. Every specialty coffee roaster has their own interpretation of what constitutes a light, medium or dark roast level - and indeed different countries use different terminology for levels of roast - so its worth trying coffees from various roasters to find one who roasts coffee to your liking.
Each episode I also answer a Frequently Asked Coffee Question and today it is…
Do dark roasts have more caffeine?
The amount of caffeine in a coffee bean is set by the coffee bush it grows on - this is because caffeine is actually a chemical produced by the plant as one of its defence mechanisms against pests. Caffeine levels in coffee naturally vary from bush to bush and place to place in response to insect attack. Fewer insects chomping on the leaves or boring into berries means lower caffeine levels in the beans. Cooking, or roasting, coffee does not increase the amount of caffeine in the bean. In fact, cooking reduces the amount of caffeine ever so slightly, so a darker roast of a particular coffee will have marginally less caffeine than a light roast of the same coffee. So why do people commonly believe that dark roasts have more caffeine and so are more likely to keep us awake? Partly, I believe it's because caffeine is bitter and darker roasts develop more bitter compounds, so we assume the extra bitterness equals more caffeine. It may also be due to the increased porosity and solubility of darker roasts which allows caffeine to be more easily extracted than it is from lighter roasts. If you actually want a substantially more caffeinated coffee either increase the amount of coffee you are using to brew with or drink Robusta coffee. Which at twice the amount of caffeine as the Arabica bean, should get you jumping around the room!
Thank you for listening to this episode of The Coffee Drinker’s Guide and that was all about roast level. I hope you found this useful. Let me know if you switched to a different roast level and are enjoying your coffee more now. If you want to help others get more out of their coffee, tell your friends about the show and rate and review this podcast wherever you listen to your podcasts to help other coffee curious people find the show too. In the next episode we take a deep dive into the topic of coffee strength - it's a bit of a mind twister so you may want to have a coffee before listening to that one! Hit subscribe so that you don’t miss it. If you have a question about coffee or a topic that you would like me to cover please get in touch. I’m on Instagram @thecoffeedrinkersguide or email me at thecoffeedrinkersguide@gmail.com. Thanks to my executive producer Viel Richardson at Lusona Publishing and Media Limited. You can find him at lusonapub.co.uk. Until next time I’m Angela Holder thanks for taking your coffee break with me - the best way to tackle life is one coffee at a time and here’s to better coffee
The Coffee Drinker’s Guide is a Blue Sky Coffee Project