Non-stop coffee dream. How Quality Control (QC) Works at A Roastery

After working as a quality control (QC) and a roaster at a roastery for a couple of months, I have a vivid idea about the entire production at a roastery. But in this article, I will only focus on how quality control should include then probably elaborate on other sections at a roastery. At the beginning of this blog, I categorize the work of QC into four sections as below,

1. Green Coffee Procurement & Sample Roasting
2. Nailing Out A Perfect Profile for A New Coffee 
3. Testing Recipes for Making Coffee
4. Improving Production Roasts

Then I will explain each section and the required tools for doing QC.

Green Coffee Procurement & Sample Roasting

Required Tools: Sample Roaster (IKAWA, Roest or Probat), and Green Coffee Scoring Form

This really depends on the scale of a roastery. Since most of the importers can provide roasted samples for clients to try, not every roastery owns a sample roaster (i.e. IKAWA, Roest or Probat). But for some on a large scale, which may buy over 10 bags of each coffee, they tend to cup the coffee based on their sample roasting profiles, which is easy to adjust to their roasting profiles. Then, the request of green samples is reasonable for them.

About the green coffee procurement, which coffee shall be chosen for being on the shelf?
First, what does this company look for? We can decompose this question into flavors, roasting level and types of brewing the customers usually do.
Second, confirming with the head roaster and cup with him/her whenever the decision is about to make because he/she is the one roasting the coffee.
Third, the affordable price and quantity of each coffee. This will definitely affect the life cycle and the storage of it.
Forth, for some, they may also care how to market the coffee if there is any point they can work on.

It will take a while for anyone to get acquainted with communication and negotiation probably. However, scoring on coffee after calibrating with roasters or previous quality control can facilitate a similar value to coffee. It seems complicated and time-consuming for the entire purchase strategy to make. But it's shortening as you are familiar with the work, then you may be authorized to decide the coffee yourself as you prove the coffee has the potential to satisfy your accounts.

Scoring Calibration with Roasters

Nailing Out A Perfect Profile for A New Coffee

Required Tools: Moisture and Density Machines (i.e. Synfco), Sorting Sifters, Production Scoring Form, Color Reader (i.e. Synfco, or CM-100), Espresso Machine, Pour-over Sets, and TDS Refractometer

When a new coffee has been purchased and arrived at the roastery, nailing out a proper profile for a new coffee is the priority as other stocks are running out. Before roasting, we have to investigate the green coffee by testing moisture and density, and screening size so that roasters can make a decision on a roasting strategy according to the data.

Then roasters may figure out several roasting profiles and require a sensory examination from quality control. Because roasting profiles are customer-oriented than seeing the potential of coffee, which a roastery looks for as procurement, the grading system on production shall be different from it.

When scoring on roasted coffee, the reasons to back up what you score are really important. It will give roasters a clear idea of how the roasting can be improved. Besides the flavors you should notice among cups, the roasting defects (i.e. underdevelopment, scorch, baked or overdevelopment) and probable causes from the roast or storage problems are also needed to be aware. 

Based on cupping, we pick up a perfect profile for the coffee. After that, we do a color reading on outer and inner bean color to see how heat transfer on it. According to the deviation between outer and inner Agtron numbers, we decide how the coffee should be used for. In the roastery I work for, delta 20 is for filter roast, 15 is considered as omni-roast, and below 10 will be seen as an espresso roast. The protocol can vary from roasteries.

Moreover, we expect how it should taste good in the way of making it. Therefore, it's important to test an espresso machine if the coffee is roasted for espresso. And for batch brew, the filter roast coffee should be tried on batch brewers or other pour-over gadgets (i.e. V60 or Kalita). Also, since we don't let our clients down. Checking the total dissolved solids (TDS) in a cup can help us predict how our clients will brew the coffee easily or not. Usually, we look for 1.25 to 1.35 when brewing 20g to 340ml.

Testing Recipes for Making Coffee

Some accounts may need the advice to make coffee consistently and professionally. Thus, when testing on the new coffee, QC shall offer the profile description and a ratio of ground coffee to water for filter or ground coffee to yield for espresso. Sometimes, in even more detail, the grind size, temperature of the brewing water and the length of brewing are asked.

Improving Production Roasts

After the coffee is on-shelf, QC has to do the job of checking and cupping every roasted coffee on production. Here, the production scoring form is required to measure if the coffee maintains its quality. Ideally, this shall be done before sending away the coffee to accounts. But in reality, roasting is arranged according to the orders and follows up with the in-time delivery to keep the freshness. Then the cupping is seen as checking if it's still in the quality criteria and the condition of green coffee. 

Conclusion

It seems a lot of work for being QC in a roastery. However, it really depends on the scale of the company and the number of coffee they want to have at a time. It can either occupy a complete full-time position or take a little part of roasters' work. Hence, it's no surprise to see QC titled with other positions. It can be very stressful when there are over 20 or 30 coffee awaited to cup and grade. Not only you have to keep your senses keen, but you also have to use the same protocol to treat every coffee equally. Meanwhile, QC is taking the responsibility of admitting the roaster's work and giving a green light for delivery to customers.