One of the most crucial parts of running a roastery is choosing your next lot of coffees.
You may choose to visit the importers website or discuss the lots available over the phone. Alternatively, you may be choosing for next year’s harvest and ordering samples six months in advance.
When the green coffee arrives, you will usually have between 3 and 20 samples to taste. You will then have to optimise the roast to get the best understanding of the coffee.
The 50g (1.76oz) of green you receive is just a snapshot of the coffee. It must present itself well enough to make the cut and for a purchasing decision to be made.
This is when sample evaluation takes place. However, sample evaluation roasting needs to be straightforward and standardised, with an open mindset to explore and understand the potential behind the coffee.
As a roaster, you must determine whether the coffee meets your specifications and whether you can profile it to highlight the qualities you are looking for.
To learn more about sample evaluation roasting versus roast profiling, I spoke with the owner of Raf & Co, Raf Mlodzianowski.
What is sampling roasting?
Sample evaluation roasting is done to analyse samples of coffee for a specific purpose.
These include grading coffees and scoring them to decide how much a coffee can be sold for, and more.
It is also done to identify defects within the green beans, and help determine purchasing decisions in a roastery.
The purpose of sample roasting is not to roast the coffee to perfection. It would be near impossible to do the first time, especially with a small sample.
“Sample roasting is a method of roasting coffee that helps you understand the full breadth of what a coffee can offer,” explains Raf, who is also a Q grader and AST in roasting, sensory, barista, brewing, and green coffee.
“We don’t want it too light or too dark, as we could miss certain characteristics. It is not about creating a roast to suit the way you want the coffee to taste. It is about finding the middle ground in a roast so that you can understand the potential of the coffee you are testing,” he says.
For instance, if a roast is too light, the coffee may lack sweetness and balance. Alternatively, if the roast is too dark, bitterness may mask any acidity or defects within the coffee.
When sample roasting, it may be beneficial to think of it like cupping. During a cupping session, the amount of water to coffee, temperature, and brewing method is standardised,
Therefore, you only taste the difference between the coffees and not which coffee has been brewed best.
“I like to use the Coffee Quality Institute roasting rules as a base,” Raf says. “Keeping the roast time between 8 and 9 minutes and trying to manage the colour so it is a light-medium roast.”
This way, you can understand whether the coffee could be roasted better to determine whether it meets your specifications.
Another key part of sample evaluation is green coffee grading. This includes checking the moisture content and density, along with a visual inspection for defective beans.
The Specialty Coffee Association Green Coffee Defect Guide is a particularly useful tool when analysing green coffee.
How does sample roasting differ from roast profiling?
Roast profiling allows roasters to be more creative.
Once the decision to buy has been made, you can now bring out the potential observed in the sample evaluation.
“Roasting is a bit like art. We all have to learn the same fundamentals. But what makes roasting fun is tasting all the different styles out there.”
The fundamentals can take time to learn, as there is much chemistry and physics involved. Just as there are different parameters to contemplate when brewing, roasters have just as many to consider.
As density and moisture content differs between beans, different thermal energy is needed to ensure heat penetrates the bean. This is what creates the chemical reactions that unlock the flavours within.
Roasting too quickly may result in grassy, green flavours that may taste underdeveloped or sour. It is likely the bean will not be as soluble as you desire. This means customers will have to set their grinders to an extremely fine setting to get a balanced expresso.
Furthermore, if the rate of rise (RoR) crashes, the energy in the roaster will also stall. This means the chemical reactions inside the bean will be hindered, and the molecules will not build into the complex compounds we desire.
As a result, they may create unsavoury flavours such as cereal or wheat in the cup, and a definitive flatness.
When profiling, it can be beneficial to write a list of specifications you aim to achieve from a roast. For instance, bringing out good body or solubility for espresso.
Then, while cupping, you can test the roast profile against your list. This allows you to measure your successes and change one variable at a time to get the desired result.
Two different roasters will never roast a coffee in the same way. They will each identify and highlight different characteristics from the same coffee. This is why many consumers have their “favourite” roasters.
‘The secret is to use your senses,” Raf explains. “Focus on the smell, the colour, and sounds while managing your machine in order to avoid roasting too fast or slow.”
Why should both be an essential practice for roasters?
Roasters can benefit from grasping an understanding for both of these perspectives.
Sample evaluation is key in making informed decisions when purchasing coffees. It ensures you select a variety that suits your needs, identifies defects, and determines the quality of the coffee.
It allows you to create a simple, repeatable roast that will save time during sample roasts. Furthermore, it enables you to judge the coffees with a uniform starting point.
Learning to profile allows you to highlight the best flavours and qualities to the consumer, honouring the hard work of the farmers who have spent years cultivating their crops.
“Personally, I’d like roasters to be more open to the fact that both very light and very dark roasts are technically defects,” Raf says.
“If someone likes that profile, then good for them! This trend of saying roasts are ‘wrong’ when we don’t enjoy them is detrimental. There is no ‘wrong’ roast – unless you have no clients, and they’re telling you it’s because they don’t like the taste of your coffee.
“Even that doesn’t mean your roast is wrong. It just means you haven’t yet found the right market for your tastes.” Raf concludes.
There are countless benefits to your business from learning to evaluate samples and profile different coffees.
The more coffee you taste, especially roasts you have done incorrectly while analysing the profiles, the quicker you will improve and grasp an understanding.
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