Rob Hoos: Call for questions about roasting very small batches on the Bullet R1

In case you missed it in our newsletter, professional coffee roasting guru and author of “Modulating the Flavor Profile of Coffee” Rob Hoos has been experimenting with his own technique for roasting 150g batches on the Bullet R1. We’re giving our users a chance to ask him some of your own questions regarding very small-batch roasting (<350g) on the Bullet R1 – or questions about very small-batch roasting in general.

We have already received some great questions, but we think we’d like to open it up here, too. Any questions you have about the Why’s and How’s of sample roasting for cuppings or roast profiling are fair game, simply drop us an email at [email protected]


It would be good to see what questions have already been asked.

Same here; I’ve done 350g roasts, usually when I have an odd lot left, but haven’t gone with less.

I signed up for the newsletter but unfortunately too late for this. It’d be great to hear about experiences with sample-size roasts.

@kafei - for those who missed the newsletter ? How can we see what was in there ?

And how to sign up for future newsletters ?


You can sign up here: Aillio Technology Co., Ltd (link accessed from the website)

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@derrxb thanks, how can I gain access to the previous letter about Rob Hoos very small batches. ?


I’m not sure where to get this. @kafei might be able to help. But here is a list of all the previous newsletters sent out so far: Aillio’s Newsletters Archive

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I don’t think the newsletter with the Q&A with Rob Hoos is published yet?

I just found out in the archive - apparently you are right and the 07.02.2022 newsletter just stated that there will be Q&A.

Since I wasn’t registered to the newsletter I only saw it when I logged in to (not the forum).

Anyway, thanks, I’ll now be able to follow.

The Newsletter with Rob hasn’t been released yet, just the call for questions. :slight_smile:

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@kafei could you post the questions you’ve received so far ?

There have been a lot… We’ll probably have to group them together rather than take them one by one. But as you can imagine, there are questions about specific power/fan/drum settings or approaches to roasting different kinds of beans, how to scale up, drop temperatures, roast phases, etc… They run the gamut.

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Hello Rob: With dense hard beans (high altitude Central American SHB@11% moisture) I would like to get your view on the use of the fan settings.
D9, F2 and P9 at a charge temperature that matches the batch size is a given. Then watching the BT probe reading (not the IR reading) and color of the bean I adjust power down but would like some opinion on how and when to change the fan speed up to F3, F4, or even F5.

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Hey @Darlings_Coffee , I just want to make sure I understand the question: Are you asking Rob’s thoughts on setting the Power and Drum to Max on every roast, while only adjusting preheat temperatures (according to batch size) and then using the bean probe and color to determine when to slow the roast using the Fan?

Honestly, I’d appreciate a how-to guide. I have absolutely no idea how I’d approach 150g on the bullet, or how I’d make meaningful observations about a sample roast of that size. How much should I rely on the IBTS? Is the BT probe totally irrelevant? What preheat, power, fan, and drum settings do I use? Am I relying primarily on scent/visuals? What do I do with the information gleaned from a 150g roast? Why isn’t Ken Jennings the permanent host of Jeopardy?


I do 300g batches when I test out a new coffee but was super interested in this topic. The idea to profile 150-200g would be ideal to avoid wasting greens :slight_smile:

Hi Rob,

-Would love to see your approach on sample roasting with 100/200gr on the Bullet. And if you would, pls include the density/ moisture of the beans you use too.

-Do you use the same approach when sampling arabica vs robusta (or other varieties)?

Thank you! And thank’s to @kafei too for this topic.

I would like to ask Rob: How do you feel about roasting 100g batches on the Bullet?

On his most recent Iteration box set, he used the Bullet to do a sample roast, which was really exciting, except that he used 150g for the roast.

100g green are included in the set, which makes sense because 100g is a fairly standard sample amount.

That said, the fact that he chose to roast 150g for his bullet sample roast has left me wondering if Rob thinks 100g is too small for the Bullet.

Very exciting to hear Rob is still working with the Bullet!

Here’s mine if you’re still collecting @kafei

My question is more about “what next” - Once the sample roast results are cupped for the bean’s taste profile, what is the recommendation on how to scale to a “full” batch (“full” being relative, it can be 350, 500, 750, 800, 1000g).


In case not everyone is receiving the Aillio Newsletter, the long promised Rob Hoos Q&A on small batch link was just recently sent out: (Very) Small-Batch Roasting on the Bullet w/ Rob Hoos - aillio

I looking forward to reading it…