Thoughts on 350g batch size?

Roasting on the Bullet
1

Hello,

I recently purchased an R1 V2 and am getting accustomed to the controls and behavior of the machine. My roasts are strictly for personal consumption and I want to make sure there are enough beans in the machine to get good sensor readings. For this reason, I am think of 350g-ish batch sizes — which also works for the 1kg qty of beans I typically buy.

Thoughts on 350g? Too small? At one point during some roasts, I noticed some sudden fluctuation in the bean probe sensor that didn’t seem to correlate with the IBTS trends. Also, the gap between bean probe temps and IBTS seemed fairly large. I wasn’t quite sure if that was due to only having 350g in the roaster or not.

I have seen the article on micro batches of down to 150g but think that is probably too small for me.

Thanks.

2

Hi, 350g is a nice batch size. I’d suggest sticking to one batch size for a while until you get a feel for the controls and how the roaster behaves. 350g may not be enough beans to cover the bean probe, which may be causing those fluctuations. But it’s OK to ignore the bean probe readings, the IBTS alone will give you a repeatable, predictable reading.

Over time you’ll be able to better understand the difference between the bean probe term and the IBTS temp and it may become more useful for you. Personally, I pretty much ignore the bean probe temp unless I am roasting a 1kg batch of dark roast. I find it really useful to follow the bean probe temp when it is nearing second crack and above.

Just because you mentioned curve fluctuations, I thought I’d add my 2 cents - I know the recommendation is to keep the drum speed at d9 but I think that using D9 on a 350g batch size flings the beans around too much. when you lower the drum speed, the roast and ROR curves smooth out quite a lot, and the fan speed changes don’t make such a dramatic change. You might find it easier to control the roaster at lower drum speed settings.

3

Thanks for the detailed response. I spent a lot of time looking at roast profiles yesterday and did notice the bean probe had some utility but generally for larger batches. I also decided to move down to D7 after reading that beans can get pinned to the side for smaller batches. The last thing I am wondering about is fan speed. My default F2 through the roast seems too low to push out the chaff, so I will probably boost to F3 and then F4 during the last 2/3rds or 1/2 of the roast.