More than just brewing and drinking go into making coffee. That’s merely the last action. From the field to the cup, the manufacture of coffee is a highly complicated agricultural commodity. To offer quality, everyone in the coffee chain uses science in the background. This article briefly examines the impact of Coffee bean moisture and density on the ageing of green coffee.
Coffee bean moisture is important. The quantity of moisture in the beans determines their maturity, how much drying is necessary, and how much weight is lost during storage and roasting, all of which affect the final product’s quality.
The moisture content of green coffee, to put it simply, refers to the amount of moisture present in the coffee bean. Water activity, a measurement of how much or little water may possibly change and interact with other microbes like mold and yeast, should not be confused with this. We employ a moisture tester to measure moisture.
When coffee is dry milled, it should preferably be dried until the moisture content is between 10 and 11%. More interactions between microorganisms are possible when there is an excessive amount of moisture. Due to this, mold, bacteria, etc. are more prone to grow on high moisture content coffees. As a result, 9-11% is the appropriate moisture range for speciality coffee, with 10-10.5% being the best target. In light of this, we exclusively sample coffees that fall within the range of 9-11%, with very few exceptions (such as novel relationships, type samples, etc.). Since they have a high potential to alter flavor and introduce undesired mycotoxins, mold and bacteria are ultimately the last things we want contaminating our coffee.
A coffee bean’s moisture level is also crucial for roasting. Because the exterior of the bean roasts more quickly than the inner does when there is insufficient moisture, the coffee roasts too quickly and develops dry, papery, grassy, and undeveloped notes.
Getting the Best Roast out of the Bean
The amount of moisture in the green beans dictates how the roaster is set, which determines the final blend’s flavor and consistency. For instance, a conventional product is created by roasting a Colombian with a moisture content of 9.5% at 400 °F for 2 minutes. If the Colombian batch after that had a moisture level of 12%, the same settings would result in a different outcome from the expected one. To get the desired outcome, roasting time and temperature modifications can be made based on the moisture level of the second batch.
The main method for calculating shrinkage, which affects the bottom line, is moisture content measurement. Data on shrinkage may be used to determine cost pricing structures by using realistic parameters.
Moisture has two effects on the grinding process. High moisture levels will result in uneven bean passage through the grinder, which may clog the machine. Dry soils might lead to issues with static electricity at lower moisture levels. The coffee extraction rate is also impacted by the grind size. If the grind size is either larger or smaller than it should be, it has a considerable impact on how the coffee is perceived to taste.
The ratio of mass to volume is called density. Density is the most critical factor in our green analysis when buying coffee, maybe even more so than moisture, with moisture typically coming in as a close second. Since denser coffees degrade more slowly, higher density is desirable in terms of density.
We just place coffee beans in a graduated cylinder to determine density by counting the grams per milliliter that are there.
What then affects density? Density is significantly influenced by the soil’s composition, therefore what is “optimal” differs not only from origin to origin but also from farm to farm (even within the same region). Generally speaking, the optimal density range is between 0.7 and 0.75 g/ml.
Anything with a lower g/mL concentration is probably going to fade more quickly in storage and have a shorter shelf life.
We utilize moisture and density as guidance when buying coffee or managing current inventory. They not only provide us with information on the roasting process, but they also provide us with information about the potential shelf life of the green coffee. With this knowledge, it stands to reason that density and moisture content may make or break a choice.
Now that you are more knowledgeable about some of the science involved in coffee, you might want to take your morning cup a bit more leisurely.