How to scale up a roast 400g > 1kg?

Roasting on the Bullet R1
1

Hi everyone
Complete noob here…just started roasting and I have a query
I have found a great recipe that I like using 400g of coffee beans
If I want to scale that up and roast 1kg at a time how would I go about it?
Thanks in advance
Osca

2

Hi Osca,

In my experience (and it is just my experience) the most important thing to change on a heavier roast is the pre-heat temp. I usually pre-heat to 230 (C) when roasting my standard 440g batch. With anything close to 1 kg (I usually do 880 when I go heavy) I will pre-heat to 280. I leave the other set points the same.

Worth a shot, adjust as you taste.

d

1 Like
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Thank you very much.
I will experiment with that
Really appreciate your help

4

I’ll concur with @dpiette.

I charge my drum to about 464⁰F for 400g and up to 550⁰F for 900g batches, although I do vary the charge temp sometimes for beans that need a lot of drying time.

When you charge, notice the IBTS and bean temp graphs in the first 60 seconds. IBTS shoots down, then gradually comes back up sensing the room temperature beans beginning to heat. Bean temp starts high and comes down gradually from the initial charge temp, sensing the air temperature. The air will be cooling quickly as the beans soak up that energy. During charge, air and bean temp are converging as energy is exchanged.

Essentially, more beans, and you need more energy in the air to transfer and get the drying process started.

Charge is a lot more fun on the Aillio because you get to see both infrared bean temp and air temp and see how they interact when heat is exchanged.

Edit: is bean temp an air temp sensor or a drum temp sensor? I know there’s induction heating directly to the drum, but not sure where exactly the bean temp probe is located. I guess it’s also worth noting my ignorance.

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5

I really appreciate your answer. That’s exactly what I needed to know.
I’ve been kind of using trial and error to get the graph to plot the same line using different quantities of beans and different pre-heat temperatures, it’s going pretty well (I believe) but thanks again

6

It’s a thermocouple in the lower left of the front plate. A small piece of metal that sticks into the bean mass. It measures what it comes in contact with, so in an empty roaster: air; a charged roaster: it’ll be a mix of beans and air, depending on how many beans and the drum speed (how high the beans are lofted).