We have been observing and collecting data in Santa Elena as part of the Catracha Quality Project to improve upon green coffee processing strategies. (See related Catracha articles here). But once the coffee is ready to ship from Honduras, we cannot ride along in the container as it makes its ocean journey to Oakland, California. We expect the conditions to be harsh and accordingly have elected to ship Catracha coffee in GrainPro at an additional cost of about 5 cents per pound.
Since we have data loggers from the Catracha Quality Project that measure temperature and relative humidity, we decided to place two in the same bag of exported coffee; one inside the GrainPro packaging and one inside the Jute bag but outside of the GrainPro packaging.
We hope that the information gained from logging the ocean journey can help us understand the impact of packaging on the longer term shelf-life of coffee. Our data collection is certainly not enough to establish clear cause and effect statements. But having the data to analyze helps us to form hypotheses for future data collection under more rigorous scientific controls.
The data loggers were placed in the bag of exported coffee for Jose Isabel Sanchez on June 15th, right after the coffee was milled at the RAOS cooperative in Marcala, Honduras. In the days before being placed in the exported bag, the ambient temperatures from each data logger recorded a high of 30° C (86° F) and a low of 19° C (66° F). The relative humidity fluctuated from a low of 60 during the day and a high of 80 percent during the cooler nights.
After the coffee was placed into the Jute bag and GrainPro packaging, temperatures remained relatively similar in both environments while inside of the container. In both instances, the temperatures started around 28° C (82° F) as the coffee was loaded into the container and then began to rise towards 30° C (86° F) as the container was hauled to the warmer Caribbean coast where it was loaded on a ship in Puerto Cortez, Honduras, and then floated south through the Panama Canal. When the coffee reached the cooler northern Pacific coast and landed at the Port of Oakland, the temperature for both data loggers gradually dropped to lows around 20° C (68° F).
We observed one notable variation in temperature when the coffee was unload from the container in Oakland on July 19th and stored in the warehouse until the 28th (when the data loggers were removed from the coffee). During this week in the warehouse, the data logger placed in the Jute bag but not in the GrainPro packaging fluctuated about 3° C (during a 24-hour period) while the data logger inside of the GrainPro packaging fluctuate less than half a degree Celsius during the same period of time.
In contrast, the variation in relative humidity between the two data loggers along the journey was more significant. The data logger inside the GrainPro packaging remained virtually unchanged at 65% relative humidity (%rh) from the time the coffee left Honduras until it was taken out of the GrainPro packaging in Oakland. The data logger in the Jute bag (not inside GrainPro) jumped from 60%rh, when it was placed in the container, to over 70%rh in just a few hours. Along the journey the, the temperature and relative humidity remained high in the Jute bag and continued to rise, eventually peaking at above 75%rh, when the journey turned northward along the Pacific coast where the relative humidity in the Jute bag gradually fell to 50%rh. When the container was opened and the coffee was moved into the warehouse, the relative humidity in the Jute bag began to rise and fall within a range of about 3% during a 24-hour period.
The data collected suggests there are probably going to be temperature fluctuations of at least a few degrees every day for periods of months during warehouse storage that might be mitigated when the coffee remains packaged in GrainPro. Likewise, we have learned that GrainPro packaging might be an efficient way to manage exposure to high relative humidity during the long ocean journey. An important next step is to understand how temperature variation and exposure to high relative humidity impacts moisture content and water activity in green coffee.
For Jose’s coffee, the moisture content measurement in Honduras for the pre-ship sample was 11.6% and the sample analyzed at Royal when the coffee arrived in July was 11.7%. The water activity for the pre-ship sample was .54 aW and the arrival sample was .58 aW. The average cup score rose from 85.5 (preship sample) to 87.5 (arrival sample). In short, we can say that the journey did not negatively impact the coffee.
Unfortunately, we did not have a control (a bag of Jose’s coffee unprotected by GrainPro) and so it is impossible to reach any conclusions about the relative impact of packaging in this instance. On the other hand, Jose went to great lengths to harvest and process his coffee. So taking care to honor his efforts from shipment, to storage, to roast, to brew has meaning even when we fall short of producing scientific absolutes.