Once a specialty coffee roaster has sourced green beans, the only way to determine their quality and flavour is by roasting and cupping them. To do this, roasters will carry out what’s known as a sample roast.
Sample roasting involves roasting a small batch of green beans to reveal their characteristics and uncover any hidden defects prior to production. It can save time and money for both farmers and roasters, as it’s an effective way of identifying any potential problems early on. Once roasted, the beans will usually be ground and cupped according to a set of protocols outlined by the Specialty Coffee Association (SCA).
To find out more about sample roasting, I spoke with Starbucks consultant, champion barista, and MTPak Coffee Brand Ambassador, Ishan Natalie.
What Is Sample Roasting?
Before specialty roasters offer a new coffee to customers, they first need to perform a series of checks to reveal any defects and ensure it meets quality standards. Sample roasting is a quick and cost-effective way of performing the appropriate checks. In its most simple form, it involves roasting a small quantity of green beans, typically between 50g and 250g.
In sample roasting, the roast level tends to be light and neutral as darker roasts may mask any defect or issues in the green beans. The sample roaster’s skill is important here as the beans need to be roasted just at the right level to reveal all of their intrinsic characteristics, both positive and negative.
The roast level should not accentuate or obscure any of its qualities. At the same time, the roaster also needs to ensure that any defect in flavours is not contributed by the roast itself.
According to an article by Atlas Coffee Importers, over the last 100 years, equipment has been developed that is specifically designed to roast and prepare these tiny samples for evaluation. While in a normal roast, the roaster tends to focus on one batch at a time, in sample roasting it can involve operating up to five drums at once.
Ishan Natalie is Beverage & Operations Resource Lead at Starbucks South Africa. Over the last few years, he’s been involved in establishing the coffee chain in the South African market, contributing two decades’ of coffee sector experience to help make it a success. He works closely with roasters in everything from sourcing to cupping, and tells me that roasters must take especial care when sample roasting.
“You will usually receive small samples of coffee,” he says. “This means you can get it wrong quite easily if you don’t pay attention. You risk destroying really delicious coffee and subsequently telling the farmers their coffee is no good.”
What’s The Purpose Of A Sample Roast?
There are a few reasons roasters perform sample roasts for their green beans.
First and foremost is to assess the quality of green beans before making purchasing decisions. Although some obvious defects, such as those inflicted by insects or fungi, can be easily identified by a simple visual assessment, some defects like “quaker” can only be detected after roasting.
Quakers are beans that fail to properly react during the Maillard stage of roasting, generally due to unripe coffee. They can be identified by their pale orange or khaki appearance, and emit a rancid toasted peanut aroma when roasted.
Through sample roasting, specialty roasters are also able to attain a better understanding of the beans, from aroma and flavour notes to density and moisture content. According to Jonathan Rubinstein in his book, Joe: The Coffee Book, sample roasting allows roasters to get a good sense of what the production roast will be like, allowing them to make informed decisions early on.
However, he also notes that given the differences in equipment used in both types of roasting (sample roasters being smaller than production roasters) there could be some variation in quality and flavour when it comes to roasting large batches of the same beans.
The Importance Of A Consistent Roast Profile
Generally, uniformity and consistency are the main objectives in a sample roast, especially when the aim is to compare the quality of multiple lots of green beans.
In particular, each batch of a sample roast should have the same roast profile. This is to make it easier to objectively evaluate various coffees and ensure that any discrepancy is not as a result of varying roast profiles.
To aid roasters, the Specialty Coffee Association (SCA) has set out a useful set of protocols for sample roasting. The protocols include recommendations on roast level, roast time, cupping, and storage methods. Specifically, they state that the sample should be roasted between eight and 12 minutes, no longer than 24 hours before cupping. They also state that the beans should be allowed to rest for at least eight hours after roasting.
During a sample roast, light, probe and gas pressure meter should all be present to help achieve consistency. Good lighting allows better inspection of the bean colours, while a probe is important to accurately measure drum temperature. A gas pressure meter gives a clear indication of the heat level supplied to the beans, which the roaster can monitor and adjust accordingly.
Ishan says that in his experience, achieving the right temperature in a sample roast is always the most difficult part. This is because the internal and external temperatures are working in opposition.
“My tip is to prime the sample roaster by roasting a batch of cheaper beans, which will reduce fluctuations in temperature,” he says. “I’ve learned to choose a set temperature – usually below 200°C – and avoid fiddling with it.”
It’s a good idea to monitor each stage of the roast, including charge temperature, time, yellowing, browning, first crack, and the end of roast.
Depending on the final objective, sample roasting can be used for cupping sessions or events for the purpose of sales or education. Under these circumstances, consistency may be secondary as accentuating the coffee’s best qualities is key. Each sample may then be roasted differently since you want to put out the best flavours on the cupping table.
For specialty coffee roasters, sample roasts plays an important role in finding the perfect coffee for their customers. It’s a quick and cost-effective way of testing the quality of green beans and ensuring they are free of defects, saving both time and money for all those in the supply chain.
Once a sample roast has been carried out, the roasted beans must be stored before being cupped. To limit contact with oxygen, light, and moisture, the SCA suggests using airtight containers or non-permeable bags to store them before cupping.
At MTPak Coffee, we offer a range of different packaging options that will keep your coffee in the best condition before cupping. Our sustainable coffee bags can be customised to include degassing valves and resealable zippers to prevent exposure to external factors, with the capacity to be used again and again.