Adusting Technique: The Secret to Brewing Tasty Light & Medium Roast Coffees
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Adusting Technique: The Secret to Brewing Tasty Light & Medium Roast Coffees

This article will explain the differences between light and medium roasts, how they are brewed differently and what’s unique about each one of them.

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Asser Christensen

Licensed Q Arabica Grader, M.A. Journalism

Brewing coffee is complicated.

Adjusting your brewing technique to various roast levels seems to add even more confusion to an already complex topic 🤦‍♂️

If that’s your attitude towards learning about coffee, then I’m sorry because there can be a great deal of help in learning about these different techniques and approaches. 

In fact, I think this article will solve a lot of the problems and confusions you have had when it comes to home brewing.

DisclaimerThis article will primarily focus on how this concept applies to manual brewing techniques; however, you can also use this knowledge as a foundation for espresso. 

adjusting brewing technique to roast level?

When you read about coffee brewing techniques online – whether the authors mention it or not – their technique is probably aimed at a specific roast level

That’s something you need to be aware of: If you’re brewing medium roasts at home, it would be foolish to expect an outstanding result with a technique aimed at light roasts and vice versa. 

There are several reasons for this: 

  • Coffees tend to extract very differently according to how they are roasted. 
  • Different flavors are emphasized at each roast level: You can use other techniques to express those in the cup. 
    • Lighter roasts: More fruity and floral qualities call for a lower concentration (lower TDS) and more clarity.
    • Medium roasts: More nutty and caramelization flavors can shine at a stronger concentration (higher TDS), and brewing techniques emphasize body, texture, and aftertaste.
light medium dark roast
Light, medium & dark roasts side by side. Each must be treated in their own way.

Coffee Extraction: light, medium & dark roasts

Coffee extraction is a concept that we’re often using in specialty coffee, but what does it mean? 

In its most simple meaning, it can almost be used interchangeably with “brewing,” but there is a significant difference:

When “normies” brew coffee, they do it the typical way: add a predetermined amount of water to the reservoir of the drip coffee maker and measure X number of scoops.

Brewing this way, you don’t control the different extraction parameters aside from the obvious one; coffee to water ratio. This parameter alone is all you have to control strength (TDS) and extraction yield (the percentage of solubles pulled from the coffee grounds into the final brew). However, most normal people don’t use a scale and are not aware of extraction theory, so it’s questionable how much control they actually have over this parameter.

On the other hand, when you become a bit geekier and start getting into pour over coffee (or other manual methods), you realize that you can control a bunch of different parameters. For instance: 

  • Grind size: The finer you grind, the more solids you can pull out of the coffee beans
  • Water temperature: The higher temperature, the more you can extract
  • Agitation: If you agitate the slurry, you will achieve a higher extraction
  • Brewing time: A longer contact time between water and coffee will allow more solubles to be extracted
  • Agitation: Pouring height and speed matter. Dispersion screens can affect mouthfeel.
  • Coffee to water ratio: Water is a solvent. The more water you run through the coffee grounds, the more material it will it pull out of the beans. This increases the extraction yield percentage. However, it also dilutes the final coffee beverage. So even though extraction yield is higher, the cup can be lower in TDS.
  • Water Chemistry: Different minerals in the water have different extraction abilities. High alkalinity can also block acidity, which carries many typical flavors in light roast coffees. This aspect doesn’t technically fall under extraction, but its effect is just as significant.
Light scandinavian-inspired roasting styles have spread across the world. But most coffee consumers don’t know much about extraction.

The curious case of the light roast

The main question in this article is why you should brew different roasts differently. Well, you have to do that because they extract very differently. 

And here we to pay extra attention to ultra-light roast beans. 

Around 15 years ago, it became popular to roast lighter. This trend coincided with the specialty coffee movement

As specialty coffee started booming, so did the availability of lighter roasts. 

However, while hip minimalist specialty cafes have become commonplace in most corners of the world, the brewing techniques such coffee necessitates are still a mystery to most consumers. 

Light beans are more dense and take a lot more effort to extract properly

Regular folks still use their old French press at home and know nothing about water chemistry. Unfortunately, this has created a disconnect between a significant fraction of the people who consider themselves coffee lovers and roasters that want to cater to a more geeky segment. 

I would argue that lightly roasted coffee almost has to be treated as a different beverage.

You have to throw out most of the things you know about coffee when it comes to light roasts. 

At the same time, light roast brewing techniques don’t work well on medium roasts. 

My top tips for light roasts

So you went to the local hip coffee shop and bought an expensive bag of beans called something esoteric, such as “Halo Beriti” or “Finca el Mejor.” 

Now, how do you brew them? Here it becomes tricky. 

There are several shades of light roasts out there. Some light roasts are soluble enough that you can get away with using a more traditional Hario V60 technique such as Osmotic Flow with a typical 93 C/200 F brewing temperature. 

But there are also ultra-light coffees — sometimes referred to as Nordic roasts or even “wheatgrass” roasts. The reference here is the vegetal, almost grassy flavors that a borderline underdeveloped roast can have.

For light roasts, I think these parameters are worth aiming for: 

  • Soft, low alkalinity water: Preferable between 40-70 TDS. 
  • A longer brew ratio: 1:16 or 1:17 seems to be ideal. However, the correct brew ratio also depends on your grinder’s consistency. 
  • Boiling water. Or as hot as possible. 
  • A finer grind size than usual. It’s often necessary to have a rather expensive grinder (think >$250 and upwards) to do a proper and consistent grind. If you have a typical entry-level conical grinder such as the Baratza Encore, you’ll see a considerable amount of fines (dusty powder) if trying to grind fine. So it might be better to grind a bit coarser and go for a 1:15 ratio instead. 
  • More agitation than usual. This can come from using a more aggressive pouring pattern, spinning the cone, or using a spoon or swirl stick.

Example of a light roast Hario V60 brewing recipe:

  • 15 g coffee to 250 grams of water
  • Boiling hot, 50 ppm TDS water. 
  • A fast filter paper, such as Cafec Abaca
  • Grind the coffee fine similar to a typical AeroPress or Moka pot grind size. Click HERE for image.
  • Add the ground coffee to the cone and gently excavate a divot in the brew bed (aka Kubomi) 
  • 1st pour: 70 grams of water. Give the cone a little shake to ensure proper saturation. 
  • 2nd pour at 45 seconds: 70 grams of water
  • 3rd pour at 1:15: 110 grams of water

Brew time: Finish around 2:30-3.00 

Troubleshooting light roasts

When light roasts are brewed perfectly, they can be extraordinary.

But when they are bad, they are horrible! 

It can sometimes be challenging to discern between a poorly extracted light roast and a poorly roasted one. 

Sometimes I question myself when brewing a light roast. I try everything, but it keeps tasting grassy. In that instance, I think it’s fair to blame the roaster. Your coffee is underdeveloped if coffee geeks with fancy burr grinders and proper water can’t brew a delicious cup. 

However, there are a few extra tips that are worth trying before blaming the roaster: 

  • Sometimes a lighter roast needs “resting time” or “degassing.” I think it’s fair to expect that it will taste great from around 7-15 days after roasting. However, some naturals need up to 20 days to open up. 
  • I have also experienced coffees that I deemed to be underdeveloped. However, after really long periods of resting, they tasted drinkable. We’re talking 6-10 weeks here.
  • I’m a bit uncomfortable with this because it seems like a get-out-of-jail-free card that companies can play if they put a lousy roast on the verge of underdevelopment. However, if you already have a bag of beans that you can’t get a good brew out of (and you don’t want to file a complaint to the roaster), then waiting some weeks might be worth it. 
  • When brewing lighter roasts, it’s necessary to use a fine grind size. This creates issues because finer grinds are more likely to clog or stall the brew. So an essential aspect of the brewing process is how to avoid this. You can, for instance, buy specific coffee filters such as Cafec Abaca, which has a faster flow rate than regular filters. You can use special dispersion screens such as the Melodrip or Gabi Dripmaster B.
  • Alternatively; you can use recipes that rely on fewer pours to avoid clogging.

Best Brewing Method for Medium/Dark Roasts

On the other hand, we have medium and dark roasts, both relatively simple to brew. 

Since medium and dark roasts are more soluble, they are easier to brew. In addition, you don’t have to grind as fine or use very high temperatures to get a proper extraction. 

This is good because: 

  • Grinding coarser means that you don’t have to worry about the filter clogging or stalling. Or channeling. 
  • Using lower temperatures means that most drip coffee makers will be able to brew a decent cup. 
Fellow ode vs baratza Encore 2
A good grinder is essential; especially when it comes to lighter beans. The Baratza Encore is the bare minimum.

Many people who enjoy medium and dark roasts haven’t bought into the same philosophy behind the light roast segment. Instead of appreciating unusual fruity flavors, they favor thickness, complexity, and viscosity. 

Here are some tips on how to achieve this: 

  • Go for a brew ratio of 1:14 or 1:15
  • Use a more coarsely ground coffee.
  • Be careful with agitation. If you agitate the coffee too much, you’ll get more bitter flavors in your brew that can interfere with a pleasant perception of the body.
  • Experiment with temperature: The sweet spot is typically around 90-93 c. 

Check out my video on the osmotic flow method for an approach that works great with more developed coffees. 

Conclusion

Light roasts should be treated as a category on their own since they are so challenging to brew. 

At the same time, you have to be careful when you’re perusing YouTube or the internet for brewing techniques; if the brew method you pick up from online coffee gurus is intended for the wrong roast profile, you might end up with a horrendous cup of coffee.  

Further Reading: The Evolution of Pour Over Coffee


FAQ

How does the roast you give coffee affect its flavor?

The roast determines the balance of sweetness, acidity and bitterness. Dark roasts tend to have more body and flavors reminiscent of nuts and chocolate, while lighter roasts have more fruity flavors and a sharper acidity. 

How do you make light roast coffee stronger?

Light roasted coffees will taste stronger if you extract more flavor. Essentially, this means tweaking a lot of variables such as grind size and brewing temperature. 

How do you extract a light roast?

Light roasted coffees are more difficult to extract, so you have to use all tools at your disposal. Check out this article, for all the best tips on how to brew light roasts. 

What temperature should light roast coffee be brewed at?

Light roasted coffee should be brewed as hot as possible. It’s recommended to experiment with temperatures close to a boil – so in the range of 210 °F. 

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Asser Christensen

Hello, and welcome! I'm the editor & founder of this site.
I have been a coffee geek since I started home roasting more than a decade ago. Since then, coffee has taken me on countless adventures: From ancient coffee ceremonies in Ethiopia to the volcanos of Sumatra.
My background is in journalism, and today I'm also a licensed Q Grader under the Coffee Quality Institute.