How to Scale a Profile from a 6 kg to a 20 kg Roaster

One of the most common questions we get from roasters scaling to a larger machine is, “How do I transfer my small batch profile to a new and larger roaster?” The immediate thought is that it will be a 1:1 transfer. Unfortunately, that’s not entirely true. Roast times and temperatures to landmarks will all change when you move to a larger machine. This is true for almost all makes and models, and here we will provide a few tips and tricks to finding waypoints in your profile as you scale.

FINDING PARAMETERS

When a new machine is installed, seasoning roasts help us create a guide for establishing temperature and time landmarks. For example, our MCR-20 roaster is the latest addition to our roastery, and when we were transferring our lighter Espresso Blend from the MCR-6 for production, we used this blend as a reference to determine a ballpark temperature for that blend's roast level.

What we found is that 14:30 minutes on the MCR-20 during seasoning closely matched the color that we were looking for in this blend, which is the start of what we need to transfer profiles. This total roast time needs to be simplified into seconds so we can apply percentages, which ends up being 870 seconds. This will be the main variable for methods of scaling our profile.

Here’s the Espresso profile from the MCR-6 that we are going to scale up:

MCR-6 Espresso Profile Reference 

FIRST METHOD: TIME AND PERCENTAGE

Development time and mid phase percentage are going to be the key metrics we take away from the MCR-6 profile above. Dry phase is omitted since this will be specific to the machine and batch size you are doing. Below is the method we will use.

When we take this formula and apply it to the 20KG time to temp goal we get this below.

This will get you very close to replicating a batch from a small machine if you are within the correct roast level goal, which you will confirm by cupping. The final result in our roastery comes remarkably close to what our formula gave us. 

MCR-20 Final Roast Profile for Espresso

SECOND METHOD: PERCENTAGE ONLY

Roast phase percentages are a popular method of tracking and maintaining profiles during production in a roastery and has also become a way of communication across the world wide web. 

Let's look at what using a percentage-only formula gives us for roast goals and targets. 

This is very close to the results we have in the first method since we already used the mid phase percentage as a metric. The most notable difference is the dry phase speeds up and the development phase elongates.

WHICH METHOD IS BETTER?

Both approaches are worth trying, and you may find more success with one over the other. What’s most important is that you test the theory, cup the results, and decide if these are methods you introduce into your craft to move the needle.  

Happy roasting!