When roasting our coffees we are aiming to develop the natural flavours of each one to present incredibly clean cup profiles. However, we can only approach coffees with our lighter roast technique if our green bean qualities are top notch. There is a lot that can go wrong from seed to roasted bean, which is why attention to detail is incredibly important at every point of the coffee process - from crop to cup.

This is part one of a two part series on why we take our green bean quality grading very seriously. In this part we will discuss looking for the cleanest possible cup and the parts of the process that can affect our green beans, both at origin and here in Berlin.

Cherries ripening at different stages on a coffee tree

PLANTATION

A mixture of the right soil, nutrition, varietal, weather, pruning, and picking is needed to grow the perfect bean. There are factors within each of those that can cause problems later in the process, for example:

- Not every varietal is suited for every soil. Experiments and trials are necessary before even sowing the seeds that will eventually become the coffee plants.
- Slow ripening and picking at the right times are crucial for flavours, minerals, acidity, and sweetness. We ask our growers to check sugars (brix levels) to define the right point of picking. Underripe cherries are as bad as overripe ones.
- The people picking the cherries are often seasonal workers from other regions, so training needs to take place every season to make sure they know what to pick. A good wage is a good incentive to pick the right cherries.

Cherries ripening at different stages on a coffee tree

PLANTATION

A mixture of the right soil, nutrition, varietal, weather, pruning, and picking is needed to grow the perfect bean. There are factors within each of those that can cause problems later in the process, for example:

- Not every varietal is suited for every soil. Experiments and trials are necessary before even sowing the seeds that will eventually become the coffee plants.
- Slow ripening and picking at the right times are crucial for flavours, minerals, acidity, and sweetness. We ask our growers to check sugars (brix levels) to define the right point of picking. Underripe cherries are as bad as overripe ones.
- The people picking the cherries are often seasonal workers from other regions, so training needs to take place every season to make sure they know what to pick. A good wage is a good incentive to pick the right cherries.

PROCESSING

Basically, there are three main types of processing: natural, pulped, or washed. However, there is a whole new world of innovation opening up, for instance anearobics, reposados, carbonic maceration, or yeast application. The process a coffee grower chooses for their cherries is defined by weather, varietals and desired flavour profiles - but there are certain details within this that will give us the clean cup we are looking for:

- Slow and even drying, constant movement, and assessment of temperature and moisture levels are all important factors.
- As a general rule, moisture needs to be below 12% - otherwise the coffee will be baggy and mouldy before it even reaches us in Berlin. However, the coffee also can’t be too dry. We have a cut off point of 9% and we will not go below this. The right range depends on the origin.
- Naturals don’t require water during processing which is great, environmentally speaking. However, the lack of washing makes it very hard to create clean profiles with naturals.
- For our style of roasting, fermented flavours are also undesirable (although some people do like them).
- The elimination of ‘floaters’ (underripe or damaged cherries or beans) is incredibly important for high quality coffees. Low quality cherries are constantly checked for and eliminated throughout the entire process. Grade one quality beans are sometimes only 20-25% of the full harvest, with the lower qualities used for commercial coffees or sold at the local market at cost price.

Drying honey processed coffee

Ralf with naturals being dried

Controlled drying

Underwater fermentation

Drying honey processed coffee

PROCESSING

Basically, there are three main types of processing: natural, pulped, or washed. However, there is a whole new world of innovation opening up, for instance anearobics, reposados, carbonic maceration, or yeast application. The process a coffee grower chooses for their cherries is defined by weather, varietals and desired flavour profiles - but there are certain details within this that will give us the clean cup we are looking for:

- Slow and even drying, constant movement, and assessment of temperature and moisture levels are all important factors.
- As a general rule, moisture needs to be below 12% - otherwise the coffee will be baggy and mouldy before it even reaches us in Berlin. However, the coffee also can’t be too dry. We have a cut off point of 9% and we will not go below this. The right range depends on the origin.
- Naturals don’t require water during processing which is great, environmentally speaking. However, the lack of washing makes it very hard to create clean profiles with naturals.
- For our style of roasting, fermented flavours are also undesirable (although some people do like them).
- The elimination of ‘floaters’ (underripe or damaged cherries or beans) is incredibly important for high quality coffees. Low quality cherries are constantly checked for and eliminated throughout the entire process. Grade one quality beans are sometimes only 20-25% of the full harvest, with the lower qualities used for commercial coffees or sold at the local market at cost price.

Ralf with naturals being dried

Controlled drying

Underwater fermentation

Various defects

Optical sorter

Dry mill in Kenya

MILLING

Once processed, the beans (still in their parchment) are transported to a dry mill. We like our coffees to rest in parchment until just before shipping, as green beans can be too fresh and require time to open up in flavour and sweetness. However, this parchment needs to be removed before the beans are roasted, so the dry mill’s role in the coffee process is to prepare, hull, and sort the beans before packing and sending them over to us. Again, there are many factors here that contribute to that clean cup we want:

- The coffees undergo multiple sorting processes, defined by gravity, screen size, development, and most importantly, defects.
- In Specialty Coffee primary defects are not allowed, but up to five secondary defects are allowed per 500g of green beans. Secondary defects won’t have a significant impact on taste if kept at a low ratio.
- Mills with optical sorters handle our microlots for us. These magical machines take up to three photos of each bean in order to identify defects and separate them from the rest. With at least two runs through the optical sorters, the dry mill can ensure there are almost no secondary defects.
- The coffees are then packed in either GrainPro bags or vacuum packed. We use the latter for very expensive microlots, as vacuum packing extends the shelf life of a coffee. It is very important that the vacuum seal is never damaged, and the bag is only opened just before roasting. Once exposed to the ambient conditions of a Roastery, the beans quickly change - after all, the last atmosphere they experienced was in a tropical country.

Dry mill in Kenya

Milling

Once processed, the beans (still in their parchment) are transported to a dry mill. We like our coffees to rest in parchment until just before shipping, as green beans can be too fresh and require time to open up in flavour and sweetness. However, this parchment needs to be removed before the beans are roasted, so the dry mill’s role in the coffee process is to prepare, hull, and sort the beans before packing and sending them over to us. Again, there are many factors here that contribute to that clean cup we want:

- The coffees undergo multiple sorting processes, defined by gravity, screen size, development, and most importantly, defects.
- In Specialty Coffee primary defects are not allowed, but up to five secondary defects are allowed per 500g of green beans. Secondary defects won’t have a significant impact on taste if kept at a low ratio.
- Mills with optical sorters handle our microlots for us. These magical machines take up to three photos of each bean in order to identify defects and separate them from the rest. With at least two runs through the optical sorters, the dry mill can ensure there are almost no secondary defects.
- The coffees are then packed in either GrainPro bags or vacuum packed. We use the latter for very expensive microlots, as vacuum packing extends the shelf life of a coffee. It is very important that the vacuum seal is never damaged, and the bag is only opened just before roasting. Once exposed to the ambient conditions of a Roastery, the beans quickly change - after all, the last atmosphere they experienced was in a tropical country.

Various defects

Optical sorter

STORAGE

Once milled, it takes up to six weeks for the coffees to arrive at our Roastery in Berlin. A dry warehouse at stable temperatures of around 18-20 degrees celsius is ideal. If the coffee was processed well, we can store it up to 8-10 months, but mostly we use our coffees within six months for two reasons:

- Coffee is not like whiskey or wine, it does not get better with age. Once the cherry is picked, the coffee just gets dryer and dryer. Some people freeze coffee to lengthen shelf life, but we don’t think this is very environmentally friendly, plus it is absolutely unnecessary - there is so much great coffee around and we want to share as much of it with you as possible!
- Seasonality is important to us. It ensures flavour intensity, creates a market awareness for freshness, and allows us to run an exciting range of flavours throughout each season.

Dry mill storage in Kenya

STORAGE

Once milled, it takes up to six weeks for the coffees to arrive at our Roastery in Berlin. A dry warehouse at stable temperatures of around 18-20 degrees celsius is ideal. If the coffee was processed well, we can store it up to 8-10 months, but mostly we use our coffees within six months for two reasons:

- Coffee is not like whiskey or wine, it does not get better with age. Once the cherry is picked, the coffee just gets dryer and dryer. Some people freeze coffee to lengthen shelf life, but we don’t think this is very environmentally friendly, plus it is absolutely unnecessary - there is so much great coffee around and we want to share as much of it with you as possible!
- Seasonality is important to us. It ensures flavour intensity, creates a market awareness for freshness, and allows us to run an exciting range of flavours throughout each season.

Dry mill storage in Kenya

Different origins, bean density, processing and varietals all age at different rates. This is why we keep tight control over our green bean grading. We also put a huge amount of effort in following the performance of our coffees on our own coffee bars. Our Lead Baristas meet weekly with our Roast Team for an in-depth quality control meeting. We have some of the best baristas and coffee bars with the highest approach to quality in town - so we make good use of this to ensure a delicious coffee experience every time.

Stay tuned for part two in our Green Beans series - or subscribe to our weekly newsletter for updates on our blog, coffee releases, and more…