Using a single origin, once you select the right coffee, you need to roast only that one coffee in the right way and prepare brewing guidelines. But in a blend, you have to select multiple coffees, roast them 全部 in ways that make them perform well, and work out how to combine them so they taste great as a group. Theoretically, it is much harder to curate a great and complete sensory experience in a blend, but with some origin and processing knowledge, and understanding what is involved when choosing the green beans to use can be a great help. In this article we will explore how to approach green beans when creating a blend, and what to consider to piece together a flavourful cup profile.

Let’s get to blending.

2. Origins/processes and their typical flavour characteristics

Every day, coffee is proving that one size does not fit all. Every origin, every variety, every process is all susceptible to many factors and because of this we can experience some extraordinary cups from anywhere in the world. This also means that general blanket terms and definitions should be taken with a grain of salt. What we can discuss is some general guides and trends to bulk coffees that are commonly used for blends, and how these origins and common processes can impact the results and set up the common flavour profiles.

Things to note:

1. Information below is just regarding bulk coffee lots. When creating microlots processing will create a vast array of flavours.

2. Different varieties, from the same origins and using the same processes, can behave very differently. We will not be considering varieties and their role in building a blend in this article (but stay tuned for when we do discuss them in more depth).

Processing and its impact on blend profiles

The first thing to consider is what washed and natural processing usually bring to a blend.

Washed processing

Washed processing, when done for bulk lots, will usually accentuate qualities like clarity, acidity and herbal/floral flavours. The type of sweet and fruity notes brought out by washed processing are often notes like caramel, brown sugar and milk chocolate with citrus, apple and stone fruit.

If you think about flavour in colour, like we usually do at Project Origin, you might see washed coffees on a spectrum that goes from white through to green, yellow, orange and a bit of browns or red.

Natural processing

Natural processing, will usually accentuate qualities like body, sweetness and deeper or bolder flavours. The type of sweet notes you might expect would be milk chocolate, dark chocolate and toffee with fruity notes being stone fruit and red, purple, or other dark-skinned fruit such as berries and grapes.

Thinking in colour, we see natural coffees on a spectrum that goes from orange through to red, purple, brown all the way to dark brown.

Next, we’ll look at the typical profiles per origin, noting that some origins are well known for more than one type of cup profile. As a general guide, this is how we would summarise origins and their common profiles for blending coffees.

Origins and typical cup profiles for bulk coffees

3. Designing blends using typical origin and process characteristics

3.1 Base coffees and support coffees

So, now that we’ve covered the characteristics of washed and natural coffees, and the usual profiles from different origins, how do we piece them together?

Remember our 3 common profiles?

1. Rich, chocolatey and powerful

2. Smooth, creamy and easy to drink

3. Fruity, sweet and unique

Of course, the way you choose to roast will have a big impact; however, roasting can’t create flavour that doesn’t exist in the green bean itself, it can only enhance or mute flavours that are already there. We aren’t considering roastiness a flavour here.

We’ll discuss blends as having two key players:

The base coffees and the support coffees.

The base coffees have the biggest role and should be chosen based on the main flavours the blend should have. They should be reliable and consistent.

The support coffees can be more flexible and can create more nuance or diversity in the blend. Their qualities help achieve the final expression.

3.2 The 3 common flavour profiles and how to make them

Example A

Rich, chocolatey and powerful

Example B

Rich, chocolatey and powerful

Example C

Rich, chocolatey and powerful

Example A

Smooth, creamy and easy to drink

Example B

Smooth, creamy and easy to drink

Example C

Smooth, creamy and easy to drink

Example A

Fruity, sweet and unique

Example B

Fruity, sweet and unique

Example C

Fruity, sweet and unique

3.3 Selecting the number of blend components and working out the right percentage of each component (NEW – JUST IN 26/07/23)

The number of components is a subjective decision for you to make. Some roasters favour a higher number of components for complexity, but also to minimise relying on any one coffee if it needs to be replaced with something else, perhaps due to cost reasons or supply availability. It is common to see 3-6 components in a blend. Other roasters keep minimal blend components for easier inventory and production management, picking only what is needed to get the result and relying on those coffees heavily. A blend can be created with just two coffees if they bring all the attributes you need.

Once you have found the components that bring the qualities you want into the blend, it’s trial and error using different percentages of each that will achieve the result. Sometimes changing a component by 5% up or down can make a surprising difference. That’s where your craft, your palate and your ultimate goal should take the lead in the decision.

4. Harvest times and coffee ageing (coming soon)

How to make a blend taste fresh all year round?

One great impact on the flavour and liveliness of a blend comes down to the age of the green beans being roasted. It is important to consider how to keep a blend tasting fresh throughout the year based on the availability of coffee beans from the origins you have chosen. Anyone who buys green beans should understand the harvest calendar and know that every origin has a unique harvest cycle with some regions of the world having multiple countries harvesting at very similar times.

As a roaster you want to plan your green coffee bean needs so you never run out of stock, but also so that you’re not using the same coffee for too long that its cup qualities and flavours begin to fade. As one coffee ages you should be preparing to switch it for another coffee that is fresher. This could be the same farm and origin but the following years crop, or it could be another coffee serving a similar purpose in the blend but from another country with a different harvest time.

Things to know

A. All coffee will age eventually. You should aim to use green beans somewhere between 6 and 18 months from when it was harvested.

B. Harvesting and drying conditions, including the altitude the coffee was grown at, the method and care of the drying process, and the packaging of the green coffee beans, will all affect how well a coffee ages

C. The way you store the coffee once imported (or received into your roastery) is very important to ageing.

You can’t control all these points, but you can make smart choices knowing what things will affect the ageing process of coffee.

Coffee storage in your roastery (or with your green bean importer) is something you can and should control. For longevity, coffee should be stored at a stable, cool temperature with low, controlled humidity. 18-22ºCelsius is ideal. If your local climate makes this difficult, stability of temperature is the next most important thing. Even storing at a consistent 24ºCelsius is better than coffee stored at fluctuating temperatures, like 20ºC some days and 28ºC on other days. Humidity is ideally between 40-60%. On the lower side of this range is best, but again, if this is not manageable, stability is most important. Having big swings in humidity where your green beans are stored is not good for their ageing.

Costing out a blend is a step that shouldn’t be forgotten. It is important to find a combination of coffees that pair well together to achieve the intended purpose (is it served black, milky or both?) for the intended audience. It is also important to find coffees that are accessible and will carry you through a full year in between harvests. It is equally important to choose these coffees based on affordability for bulk purchasing.

Typically, roasters will buy coffees for blends in bulk volumes because your greatest selling products are your blends. You don’t want to run out of it. Because blends are sold the most and in large quantities, it is smart to ensure that they provide a reasonable profit margin to keep the roastery operating. When considering coffees to use for blends, you need to think about how much each component will cost you, and how much the combination of the coffees will cost altogether. It’s all well and good to have a budget of, say, $18/kg for the final roasted coffee, but if 50% of your blend is costing you $13/kg, then you are not leaving a lot of room for the other 50% of coffees. This may seem like a dull or obvious point, but it is an important one to consider.

We recommend sourcing your base coffees with the full harvest year in mind. Buy them in bulk as they are the most important part of the blend to achieve the flavour profile you want. When selecting them, make sure they are the most cost competitive components of the blend.

So if your budget is $18/kg, try and aim to have the base component(s) costing $9/kg or less. If your base component can be bought at a competitive price, it gives you room for the support components to be slightly more expensive and bring a bit more character to the final result.