What influences the quality of green grain


On farms in Ethiopia, Brazil, Burundi, Ecuador or even Mexico. Everywhere there and in other countries with suitable climatic conditions, coffee is grown. Coffee trees grow there and are tended by local farmers. They take care of their well-being so that the plants grow well and ripen into cherries that hide our little treasure - coffee beans. Once the cherries have ripened, the fruit is picked and processed, most often using the natural, wet or honey method. You can read all this on the label of the roasted coffee package. You can also find out atwhat altitude the coffee trees are grown and from which botanical variety of coffee tree the beans were picked. They then came to the roastery, where we roasted them to a certain degree of roasting to bring out all their previously hidden flavours and aromas. You will also find a description of them on the package of your chosen coffee.

What thepackage doesn't say is thejourney of the beans from processing on the farm to roasting. Yet this part of the coffee bean's life is also very interesting. The green beans of the coffee tree are actually its seeds, which (if not processed) could be planted to grow a new coffee tree. For some, this is what happens. Farms grow their own coffee tree nursery with seedlings of different varieties, either to replenish or rejuvenate the farm.

However, most of the coffee beans are harvested for processing and sale. These fresh , living beans, like other organisms, "breathe" even if only at the cellular level. Oxygen therefore still has amajorimpact on their further processing. This is evident, for example, in the processing of coffees using fermentation processes. Theageing of coffee, i.e. its oxidation, is also affected by oxygen .


Theharvested coffee cherries must be brought quickly to the processing station where they aredried. Moisture could result in theformation of mould or other bacteria and the quality of the bean would be compromised. Therefore, every hour is important for the quality of the coffee during harvesting. Each batch of harvested coffee must be properly labelled to ensure proper drying and further processing. Dried green coffee beans still contain a certain percentage of water. The International Specialty Coffee Association (SCA) determines the required moisture content of these beans. To maintain its quality, green coffee needs to contain around 11% moisture after drying . More moisture would result in microbial proliferation and deterioration of the beans, while moisture below 8% would result in a loss of flavour. In addition, beans with lower moisture content would be lighter and the farmer would have to put more beans in the sack to guarantee the desired weight of each sack of coffee.

Moisture content is not the only factor determining the quality of green beans. Coffee processors also measure the water activity in the bean. The results of this analysis help determine the stability of the coffee and how it will continue to behave. These calculations help reveal the coffee's reactions leading tobrowning and alsopredict its safety against mold formation or unwanted fermentation.


For roasters, thedistribution of beans not only by harvesting batch but also by size and type is also important . During roasting, green grains heat up and turn brown. This is essentially a kind of roasting that we know at home from our own kitchen. While the larger pieces of vegetables roasted in a pan are as toasted on the outside as the smaller ones, they will be raw on the inside. That's why the roaster needs the same grain size to ensure that they are all cooked properly. This sorting is done by using different sized sieves through which the beans fall.


Thevisual quality of the beans is assessed either by machine or by hand. At the illuminated tables, defective beans are sorted. To check the quality of selected coffees, SCA states that there are amaximum of 5 secondary defects in 350 grams of coffee and no primary defects.

The colour, shape, completeness of the bean, insect damage or the presence of parchment or other materials in the coffee sample are examined.


Thedensity of thegreen beans is also measured . This measurement is made simply by using a measuring cylinder. Density indicates how many beans can fit into a certain volume. The density measure is reflected both in the financial area but also in the final cup of coffee. High density beans are more valuable because they weigh more and take up less space. At the same time, beans with higher density behave differently during roasting in terms of heating and energy consumption for the reactions caused by roasting. This also affects the quality of the final taste of the coffee in your cup.


After drying and quality control, the green coffee beans are ready torest before travelling. To stabilise after processing, the coffee is left to rest for 6 to 12 months before being transported to the roastery. At this point it is important to monitor the quality of storage. This means that the coffee rests in a dark room where the temperature and humidity of the environment are controlled.

As we wrote at the beginning, oxygen has an effect on coffee, and it affects it all the time, from the plant to the cup. In order to prevent oxidation of the coffee and therefore its ageing, coffee is most often packed in bags. These coffee sacks are traditionally jute on the outside , but inside the coffee is protected from air by a resealable plastic bag. To provide even better protection, the coffee isvacuum packed and placed in acardboard box. This ensures that the green coffee beans arrive from the farm to the roastery in the best quality.


We will devise themost suitable roasting "recipe"for the coffee that has been cared for in this way , and then it's up to you to enjoy it. Don't forget, as you take a moment with your coffee, to remember how much activity, work and people were involved in its journey to your cup. We know our suppliers andfeature their stories on our blog .