I would like to increase the batch size of a recipe (from 600g to 1kg). I know I likely will never achieve the same result exactly but does anybody have experience with this? Are there some general rules to this?
Here’s the recipe I’d like to have modified:
Bean: Indonesia Sumatra Lintong, washed (600g)
Preheat Temperature 250.00 °C (P9, D9, F3)
IBTS 177.00°C (F3 → F4)
IBTS 185.00°C (P9 → P5)
IBTS 199.00°C (P9 → P3) ( F4 → F6)
IBTS 205.00°C (P3 → P1) (F6 → F8)
End roast IBTS 208.00°C
All suggestions, knowledge and tips are appreciated.
One of the more common recommendations is to increase the preheat temperature when you increase the batch size.
I found a Sumatra Lintong roast profile and copied it to my stashed profiles and will probably make a recipe out of it.
It is for a 900g batch. It finishes at 10.5 minutes. The curve looks pretty good.
Here is a link:
The Bean Temp probe crosses the IBTS near the end of the roast which is common. When I am roasting larger batches and the Bean Temp probe crosses the IBTS, I use the BT probe instead of the IBTS to make profile decisions. I will use the BT probe to determine when to drop.
I’ve been honing my roasting skills with 330g batches and am in a similar position where I’m getting comfortable with 330g recipes but now need to increase my batch size to keep up with demand but also for improved productivity.
In terms of scaling colour represents as much as 80% of the flavour profile (see Coffee Mind’s in research paper), you will end up with a dramatically different flavour profile if you don’t lock in your colour, so keep a sample of your previous roast, and keep checking the colour with the trier and drop the beans when it matches. It’s tempting to focus on development time % and drop the beans based on this, don’t. Remember colour represents around 80%, development just 15%, MAI just 5%. Stay focused on the big numbers, nail those first and then finesse the rest.
When scaling I’m also trying to match the % weight loss of my smaller batch size, if I’ve got close to the same Agtron and the same weight loss it’s a great start and will then cup and then work on the development time to tweak the flavour further.
In terms of finding a roast recipe, you might be able to find another User with same beans to get some clues.
