Light versus dark roast

Tasting light roast for the first time is strange for many coffee drinkers because something is missing compared to the darker roasts.

But many coffee people loves it because it has some great flavours that dark roasts don’t have.

Fil 28-02-2018 14.22.02Original Coffee (OC) is a coffee bar here in Copenhagen. They always have to kinds of roast for the espressomachine: a darker roast they present as “Traditional” and a lighter roast they present as “Modern”.

It’s a very good way to communicate the taste to a regular coffeee drinker. The Traditional is in the expected area. The Modern is different.

 

But light and dark roasted coffee are not only different in taste but also to work with. So if you treat a light roast like a dark it won’t taste good. And the other way around.

If you are curious to try there is a few things to know. Because they are different to work with. Below is a list with the differences. We also talk about this in Episode 8 in the Coffee Roasting Navigated podcast.

Boenner uens overflade 12sep2016

There is no common definition of when exactly a roast is light or dark. In the U.S.A. it is common to call it a light roast when stopped before the Second Crack, but still having completed First Crack. Here in Northern Europe that would be considered a medium roast. We call it a light roast when it’s stopped before the First Crack is over – or just around the end.


List of differences

Comparing dark coffee roasted to 2nd Crack versus light roasted stopped before First Crack is over or just around the end.

1. Roastingbeans-trier-sh1
Not all beans taste good in a light roast. High grown beans is a good place to start if you want to explore roasting light.

Not any light color roast taste good. You have to explore to find what roast profile suits the given bean.

2. Dosage
This is mainly for filter/drip and french press. Regarding espresso go to #7.

When you brew a light roast: updose = use more coffee.

Light roast has less solubles than dark roast. So you need more grams of coffee.

Exactly how high dose depends on the roast and what you prefer in the taste – so go explore.

When I brew a light roast filter/drip or french press – I mostly use a dosage around 60 grams pr liter  – but goes from 55 up to 70 grams pr liter depending on the coffee. It’s different where they are the best. I even know people who do 85 grams pr liter.

Darker roasts are better at lower dosage. I have even heard of people using dark espresso roast as low as 35 g/liter.

3. Grinding
Grind light roasts finer than for dark roasts. I don’t know if it’s because light roasts are less porous or again this less-solubles. But you get more of the good taste by grinding finer.

Because of the denser bean structure, I use a longer bloom phase when making drip coffee (V60, Kalita): 45 seconds instead of 30 seconds.

4. Brew water
If your tap water is hard = has a lot of chalk … then it can make a light roast brew taste boring – compared with filtered water. This is a whole science in itself. Look up “third wave water”

cup-only-22maj

5. In the cup
When you taste it – pay attention to how the taste change as the coffee cools in the cup. Very light coffee do not have much taste around 70ºC but get interesting around 50ºC.

6. Milk and sugar
Be cautious with the milk. Some light roasts taste great on it’s own … but if you poor milk into it: the interesting taste will all be gone. Because the flavors are so delicate.

The same with sugar. Lighter roasts can be sweeter in itself than darker roast. So taste before you ad anything.

7. Espresso
Brewing espresso of a light roast is different than with darker roasts. There are different approaches. But a few things people agree on:

espresso brygningUse a large basket in the portafilter, size 18 or 21 grams for 58 mm. Light roast doesn’t seem to work well in smaller pucks.

Use longer preinfusion.

Traditional in espresso you have a rule of thumb saying: reach 1:2 brew ratio in 25 seconds. So if you have 18 gram coffee → then get 36 grams in the cup. That doesn’t seem to work with light roasts: it’s sharp, sour and do not get the aroma of the given coffee.

Again bear in mind; light roast are denser and got less solubles than dark roasts. So the good taste is not as quickly released as with dark roast.

I know of two strategies to brew light roast:
– Grind finer and pull slow long shots, like 40 seconds instead of the traditional 25 seconds. Or even 1 minute shots on a Slayer espressomachine.
– Grind so it runs faster. And go for brew ratio 1:3 (thats what I do)

To explore this try letting a shot run really long while you taste with a spoon to follow what taste is extracted. At first it is always very sour and sharp. So maybe skip the first 10 seconds that comes out. But then keep tasting along untill it gets weak (=no more taste is extracted). In this way you can tell when the good taste is extracted. In a dark roast it gets weak quicker than with the light roasts.

Here is lots to play around with. I have had great shots of light roast espresso that ran only 18 seconds to achieve the 1:2 brew ratio. And I had a shots where good taste kept coming out even after 60 grams in the cup with 18 grams coffee in the basket.

Dudley Powel from Horsham Coffee Roaster (UK) also found that running faster shots works better with very light roasts. His recipe is:
18g in – 54g out – 26 seconds

Read his whole blogpost at https://www.horshamcoffeeroaster.co.uk/blogs/news/change-your-roast-profile-or-change-your-brew-method

It all also depends on your equipment. Christian Hansen (Denmark) says he goes for brew ratio 1:2 with conical burr grinders but 1:3 for flat burr grinders. Conical burrs gives a more spread out particle distribution.

Making espresso of very dark roasted coffee seems to be best when it runs very slow and runs thick like syrup.

8. Storage
Light roasted coffee often gets better when rested a bit. For a start 4-5 days. And sometimes light roasts first peak at 3 weeks after roast date. If a coffee do not taste good in the first week – try letting it rest for some weeks.

Boris Lee once had an Ethiopian Gesha Village roast that was flavorless at first. He had given up on it but accidentally tried it after 3 months (stored in a sealed bag) – and then it was much better.

The Danish roastery La Cabra roast very light (no more than 1 minute from First Crack start). They say their espresso roast is best between 30 and 60 days.

Dark roasted coffee (roasted to 2nd crack) is best between something like 2 and 10 days. Later the oils will get rancid = taste bad (well, some people don’t notice this). When you roast to Second Crack the oils will come out. If you stop at the beginning of Second Crack the oils may not be visible right away, but will appear as small wet dots on the bean surface. If you roast longer the beans will be completely covered with oils = look wet. When the oils has come out they are more degraded and exposed – and so they quicker go rancid than in lighter roasted coffee.

James normal dark roast

But as always; taste for yourself. This is just guidelines to inspire you. Here are lots to explore.

Color scale

In podcast episode 3 we measure the color of the roast on the Agtron scale.

I just did blind tasting of a Colombia bean roasted to different roast degrees/ color.

95 Light – acidic, sweeter, no smoke

85 Medium light- acidic, sweeter, no smoke, not bitter

75 Medium dark – smoke, toast

65 Dark – high in smoke/tobacco, burnt, very bitter

95 and 85 were more alike and clearly different from 75 and 65.