This post is intended to help roasters create a consistent framework for developing a blend. In future parts to the ‘Coffee Blending’ series, I will add more tips and tricks, particularly with regards to the system itself, coffee choice and application, roasting methodology, steps for quality control, consistency, and more.

STEP 1- Define roasting style and target market for the blend. What will work based on where you are setup up? Will the clientele in your area prefer darker roasted coffees with milk and sugar? Or would a balanced medium roast flourish? Is it feasible to do any light roasting? Do you want a coffee that’s juicy, fruity and a little bright or coffee that’s nutty, creamy and chocolatey? Your roasting style will have an effect on STEP 2.

STEP 2- Determine the target price range of the green coffee per kg that makes sense in your business model/target market – What is the lowest and highest you can go to achieve sufficient profit with sustainability and growth in mind. Knowing the limits you need to work within sets the boundaries for your creativity and can put you in the correct frame of mind to achieve the best results with what you have available to work with.

STEP 3- Put together a few options from your lowest to highest target price.

Get samples of all of these coffees, the size of which needs to be appropriate for the assessment you wish to conduct. I like to pre-cup everything before assessing in espresso and/or filter and meticulously detail the coffees on SCA sheets. I believe that one of the greatest decisions and aids in understanding how coffees interact, would be to familiarize yourself with and  continuously use the SCA cupping sheet. And also, be sure to keep your cupping sheets somewhere safe for future reference. (More on this in a future post.)

Take these two blend options as an example-

It would be good practice to create your own sheet like this. You can see in the sheet above that I have a column showing green per kg pricing as well as roasted per kg pricing (factoring in weight loss from roasting, normally around 15-17%)

With regards to assessing these -I would lay out cupping bowls of all five (these coffees should preferably be roasted in a sample roaster first as opposed to a production roaster.)

(You’ll notice I’m saying five, because the only coffee that’s in both blends is the Nicaragua Datali El Diablo.)

From this cupping, you should visualize the application of all of these coffees and if it’s something that will work in your target roasting style for the blend. This approach will also help you become acquainted with understanding a coffees potential through analysing a sample roast.

If you feel that some options won’t work, look for other options to fill that gap, and repeat the process.

STEP 4- Roast test batches of the chosen coffee on your production roaster

Once you’ve decided on your options, it would be good to roast a few batches on your larger production roaster at the capacity you would roast at in a normal production scenario. You’ll need some test profiles in mind (and on paper) with the intention of optimising all the coffees individually and eventually in a way that will work well together.

I would recommend starting with 2-3 roasts of each component, with the idea of manipulating certain key characteristics in the coffee, namely final acidity profile and mouthfeel/body. Let’s assume that your target drop temperature/roast level is somewhat uniform between the different components.)

If you discover the sweet spot and have decided on coffees and base roast profiles (profiles that you can improve as time goes on) then go on to the next step.

If unhappy, go back to the previous step and repeat or, alternatively, explore where you might have gone wrong and see if perhaps it’s simply a matter of changing a roast profile.

STEP 5- Refine the roast profiles for your blend.

You’ve got your coffee options and your roast profiles dialled in (or at least to a workable point).

What now?

It can always be better.

Making incremental adjustments on roast profiles is a great way to optimise the blend over time. Say you have 10 roasts scheduled for the day to meet production needs. 3 Brazil, 3 Honduras and 4 Burundi.

  • Decide on what roast results you wish to achieve to optimise the blend, i.e. bigger body or more acidity, etc.
  • Decide which components, if not all, you wish to conduct this process on.
  • Put your ideas on paper (in roast profile form)
  • Decide how many experimental roasts you are willing to conduct to not negatively impact production from a consistency standpoint.
  • Perform experiments and finish off with scheduling a cupping date for said experiments.
  • Ensure that you have a batch of your initial blend of the same roast date to cross compare on your scheduled cupping date. This will allow you to more accurately assess the effects of roast profile changes. Cross comparing with different roast dates would be counter-productive.

Closing Words

There is certainly more to this than what I’ve mentioned above, but what I’d like to leave you with today are a few points I’ve considered to be important from the beginning of the blend creation process-

  • Use the SCA cupping form for assessing all your coffees, and keep track of everything you roast. Keeping roast profiles attached to the matching cupping sheet is even better, or at least know where to find everything in the situation where you would like to recall it.

There is a great app available for android and iPhone called Catador which uses the SCA sheet as a basis. Check that out if you’re keen on going digital.

  • If you’re not using some form of roasting software, I would highly recommend it. It’s not a deal breaker, but it’s certainly life-changing in many ways.
  • Schedule monthly roasting experiments to make sure you are maximising on your coffees. Make sure that the time you allocate to this is structured and meaningful, and always ask yourself what you’ve learnt. Need I say- document everything.

Until next time.