How to evaluate the quality of your coffee. Part 2: Sample Roasting
Sample roasting is an essential component of the quality control process at all aspects of the supply chain, all the way from origin. This is helpful for buyers, producers, importers and roasters. To ensure high quality of your coffee, there are important steps to follow in your sample roasting process. Step number one: purchase the right sample roaster. Before you take this step, read the words from Julia Rebecca Richardson, coffee professional with years of experiences in QC (Quality Control) lab at a coffee import company.
Over to Julia:
Why sample roasting is important
Sample roasting is an opportunity to evaluate the quality and uniformity of the green coffee. This can provide valuable feedback to producers, showcase coffee to potential buyers, aid in production development processes, as well as quality assurance on inventory checks, age, and any profile changes that need to be made.
Sample roasting serves two main purposes:
1.
Roasting 50 g-150 g of coffee in an uniform, consistent manner to evaluate any possible defects, faults or flaws in the coffee, and to have an overall understanding of the cup.
2.
Roasting 50 g-150 g of coffee in such a way as to highlight characteristics in the coffee for sales or product development purposes.
Julia evaluating coffee after sample roasting. Sales purpose: looking for which lot to buy for the client.
Speaking of the purpose…
Quality
When evaluating coffee for quality purposes, it is important to have a consistent, non-biased and uniform roast to concentrate on the attributes of the coffee versus the roast profile. The main goal of this process is to uncover any defects or flaws of the coffee that were not revealed in the previous green bean evaluation.
Sales
For sales purposes, sample roasting can highlight specific characteristics of the coffee such as sweetness, acidity, balance, etc., to showcase the coffee potential to the buyer.
Production
For production purposes, sample roasting can be used for quality control, understanding how the coffee reacts to the roasting process, or for revealing the potential of the coffee.
Read more about how Tim Wendelboe uses his ROEST sample roaster within different departments of his business: Sample Roasting with ROEST by TW
The best sample roaster
Some of the key components of a sample roaster by Julia:
Uniform heat distribution
Temperature sensors (temperature inside the drum and bean temperature)
Measurable and adjustable airflow/fan
A trier to have visual contact (on the photo below)
Live view, data logging and profiling
Fast cooling, ideally in a separate cooling tray
Roasting on ROEST sample roaster you have a visual contact with your beans during roasting using a trier.
Let’s take a closer look on it:
Size matters
A good sample roaster needs to be small enough to consistently roast a 100 g sample at quality standards, and needs to have the capacity to manage the roast within the quality control timeframe protocols.
CONSISTENCY
Whether you’re using the sample roaster a few times a week or a 100+ roasts a day, it is important that the roaster remains consistent with each roast. It should be able to provide an even coffee bean development repetitively, therefore producing a clean and balanced cup.
EFficiency
As a Quality Control Manager there are many tasks to follow between roasts, therefore, having a sample roaster that recovers quickly between the roasts and has enough features to free your hands to do other tasks is amazing! It’s about finding a balance, a great sample roaster would have some autopilot features, but enough basic features to give room for manual operation and creativity.
EASY & INTUITIVE
Personally, having worked with both solid drum and digital micro-roasters, a dependable, uniform, quick and easy to use sample roaster is preferable. Ideally, a good sample roaster would have a trier for a visual check of colour and to follow how the coffee is reacting to heat and air flow. The sample roaster should also be able provide an even coffee bean development repetitively, therefore producing a clean and balanced cup.
Efficient workflow of sample and production roasting at the same time. Head roaster Ludwik at Fuglen Coffee Roasters in Oslo.
Read also about key values of sample roaster by Nordic Approach.
“ROEST can reduce the airstream to a much lower volume than a fluid bed roaster - increasing the control over the roasting process. ”
Drum roaster or fluid bed?
Both have their pros and cons. This is where the ROEST sample roaster comes in. ROEST is not a traditional/conventional drum roaster. It is a hybrid of both technologies: small hot air roaster and conventional open drums. While the drum is fixed, paddles inside are agitating the coffee, and heated air passing diagonally across the roasting chamber heats up both the drum and the coffee. Since the coffee is agitated by paddles, not by high pressured air, like a fluid bed roaster, ROEST can reduce the airstream to a much lower volume than a fluid bed roaster - increasing the control over the roasting process.
Approach to sample roast profiles
Follow the live view, log your notes notes, create your own profile, and share with others. ROEST has its own user-interface webportal.
When looking for the ideal roast profiles for sample roasting, I like to have verified profiles that provide a base. I then use temperature readings as a guide, engaging with the coffee by checking the colour, smell, surface development and time, and then adjusting heat and airflow accordingly. I also make necessary changes depending on the moisture reading, bean density, origin, process, etc.
In the age of technology, connectivity to digital devices for roasting and recording profiles is a big advantage. It is great to be able to share profiles with customers, partners and colleagues. Having the opportunity to digitally take notes and record changes in the roasts is also helpful in order to make necessary changes for the next time.
Read more about Creating 50g profile - detailed report by Blazej Walczykiewicz.
My routine step by step
After the green bean physical evaluation is completed and documented, you begin roasting! I like to roast between 100 g to 120 g, that way there is enough material for a proper evaluation in-house, and there is enough coffee left for potential buyers and customers.
CLEAN & QUIET
I always like to begin and end with a clean lab. Ensure your roaster is clean of old chaff and debris and that the area is well lit. Quiet surroundings are ideal, however, having worked in a lab that shared a roastery and packing production, I understand silence is not always a possibility. That is why First Crack detection is so extremely helpful: even if the cracks are subtle, ROEST can register them for you.
Charge the beans and go back to labels and preparing other green samples. ROEST will take care of the roast for you.
TURN ON & CHARGE
Once the area has been cleaned, I turn on the roaster and warm up the machine. I then start the process of roasting. With ROEST, I am able to charge the beans, roast, and first crack detection will start the development time by itself, then drop the roast in the tray when completed. Then all I need to do is charge the next batch of greens. There is no need to wait for the roaster to reheat, as ROEST goes up to the starting point within 2 seconds and cools down super fast.
IT’S ALL ABOUT THE WORKFLOW
In the meantime, while I am roasting I am able to set up different areas of workflow. My computer is nearby for data entry and checking emails in between roasts, a scale and cupping trays for weighing up greens to go in next and labels are printed. Once the coffee has cooled down and has reached room temperature they’re packed in a dark, resealable bag with a label.
CRAFT (BUT MIND THE RULES!)
I personally view sample roasting as a craft, and the more you do it, the more you understand the coffees, different variables, and the equipment you are using. However, for starting out a basic rule of thumb is setting up perimeters around the SCAA (Specialty coffee Association) guidelines.
The roasting of coffee for cupping shall take between 8 and 12 minutes, and the cupping should take place between 8 and 24 hours after roasting.
Scorching and tipping should not be apparent.
The sample should immediately be air cooled.
Samples should be stored in a cool and dark place, but not refrigerated or frozen.
The colour should be light to medium light, comparing to either an Agtron colour tile #55 or an Agtron machine using grounds for accuracy aiming for a reading of 63 (+/- 1).
After the appropriate resting period is completed, it is finally time to cup the coffee! The article is following in the Part 3 - here.
