Consistency is key for businesses to keep customers happy and to ensure success and growth.
That said, achieving consistency can be challenging, as roasting coffee is a complex process that is affected by many variables, such as charge temperature and the characteristics of green coffee.
A slight shift in one of these variables can lead to a wide range of taste spectrum. If a customer has a different experience with each order, it is unlikely they continue to invest their money in the brand.
One way you can maintain consistency is through quality control. In essence, quality control is defined as a system of maintaining standards in manufactured products by testing a sample of the output against the specification.
Taking time to check products are consistent and reaching high standards can help ensure customers have the same experience every time and will make repeat purchases.
In the fifth and final part of our Quality Control series, we speak to the production roaster at Penstock Coffee Roasters, Rebecca Zaynidinova.
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What quality control means to Penstock Coffee Roasters
Based in New Jersey, USA, Penstock Coffee roast for wholesale customers, its own cafes, and for home customers. Working on a San Franciscan roaster, the brand is passionate about its relationships, both with coffee farmers and customers.
The brand’s aim is to get its customers more involved in the stories behind the coffees they choose to buy. To do this, Penstock Roasters custom-print QR codes on all of its coffee packaging, including its retail bags.
These QR codes direct customers to the brand’s website, which provides them with brew guides for each coffee.
An additional part of getting customers involved in specialty coffee is to roast consistently and highlight the beans’ inherent flavour and aroma characteristics.
“I firmly believe roasters should do quality control checks for their own growth and learning,” says Rebecca, who is also a licensed Q grader. “Quality control is essential for putting out consistent products for customers.”
Penstock Coffee demonstrates its passion and commitment to quality throughout its business. For instance, the brand sources outstanding coffees and performs regular cupping sessions.
More so, Penstock offers training to its retail customers in its coffee learning labs and classes and even invites customers to join the occasional cupping session.
“When we conduct any sort of quality control, we are looking for consistency,” Rebecca explains. “In a cupping, we look for the flavour profile to be within a certain target range. This includes the acidity, aromatics, body, and balance.”

The three levels of quality control
“I like to say there are three levels to quality control,” Rebecca explains.
“The first is developing a product that meets a set of standards that you, or someone else, has set,” she says.
The second level is making sure that subsequent production of this product is consistent, while the third is making improvements where necessary.
“In the broadest sense of the phrase, ‘taking measurements’ is an accurate way to summarise how roasters do quality control,” Rebecca says.
These measurements can be qualitative or quantitative, such as taking sensory notes during cuppings, tracking roasts with software, and measuring the colour of beans post-roast.
Additionally, it includes ensuring all these measurements are within an allowable range.
“Sensory data is best collected during a blind cupping, by several trained professionals in the same session, with the same set of samples,” Rebecca explains.

Blind cupping refers to cupping a coffee without knowing which one is in the cup. This gives roasters the ability to judge the coffee without any preconceived notions.
She adds the colour of roast whole-bean and ground coffee can be measured using light-refractive tools, such as an Agtron. Furthermore, roasters can be tracked using software such as Artisan and Cropster.
Penstock conducts quality control cupping weekly. On the rare occasion where a batch roasts in an unexpected way, Rebecca pulls the batch and cups it against a standard sample batch.
It is essential that sensory quality control is done in a standardised manner. For instance, many roasters follow the Specialty Coffee Association’s (SCA) protocols.
More so, roasters must do what they can to avoid psychological biases. Blind cupping sessions can help avoid this.
That said, roasters must also avoid expectation bias – when a roaster cups a coffee knowing the roast profile is wrong. This may cause them to look for differences where there are none.
Habituation bias refers to when a roaster has become so used to a coffee they are unable to notice things they did before, as they have become so used to it.
Rebecca advises roasters to put procedures in place to avoid these biases. For instance, roasters can offer refresher training and training with new references with typical and extreme attributes.
Important to note is that a roasting team is a quality control tool which needs to be calibrated and controlled just like any other piece of equipment.

The importance of training roastery staff
Rebecca makes interesting points regarding training and growing a sensory team when evaluating coffee within a business.
When asked how coffee businesses can improve quality control, she says roasters should invest in reliable equipment to take quantitative measurements and a calibrated team that is constantly looking to improve their sensory skills.
The SCA sensory training programmes, which range from foundation and intermediate to professional, are a great basis for calibrating staff. These can help them understand the attributes that a roaster is looking for in quality control.
This training should be combined with roasting training, as this can help the team understand what they are tasting in the cup.
More so, roasters can choose to take the Q Arabica Grader Course with the Chartered Quality Institute (CQI). This can help roasters effectively communicate with others along the supply chain, thus improving the overall quality of the coffee.

As part of Penstocks’ commitment to educating consumers on specialty coffee, the brand is involved in the Transparency Pledge.
Traceability of any product is a huge part of quality control, but also overlaps with ethical commitments.
It is important for roastery staff to know where the product ends up in case of a recall, but also where the coffee has come from.
Although the transparency pledge is not a solution to a lot of the inequalities in the distribution of wealth in the coffee supply chain, it is a step in the right direction for roasteries to declare how much they are paying for green coffee publicly.
Penstock declares its coffee prices on its website. The commitment Penstock hold to ethical and quality coffee is reflected in the outstanding coffee that it serves, as well as its returning customers.
At MTPak Coffee, we offer roasters and coffee shops a range of 100% recyclable coffee packaging options that can be custom-printed to your business specifications.
Choose from renewable materials such as kraft paper, rice paper, or multilayer LDPE packaging with an environmentally friendly PLA lining.
Learn more about how different roasteries conduct quality control. Read the fourth article in our Quality Control Series, or dive into interviews with our coffee community.
Images from Penstock Coffee Roasters