Feedback for a new roaster

Hey you awesome bullet roasters!

I have only been roasting on my bullet for about a week now, and this (my ninth roast) cupped pretty well. I’ve been reading Rao’s book pretty thoroughly and I think there are some mistakes with my curve, despite the coffee tasting great.

If it’s not too much for a new poster to ask, could you guys give me some feedback on what looks like it went well, and what looks like it didn’t? Overall I’d say that the origin notes came through really well, smell was amazing, and it brews great with French Press, but tastes a bit hollow as a column drip.

Thank you all,

I am looking forward to getting active here and meeting everyone :slightly_smiling_face:

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Hey Andrew (?) welcome!

That looks like a good roast. I really like the drop temperature of 218C for a “medium” roast, comfortably past the end of FC but short of SC. If you want more brightness, fruit, and acidity, you could use the same profile but cut power further starting about a minute before FC and let the RoR coast downward for a target drop temperature of say 207C, with weight loss more around 13%?

Everyone has their own preferred way, but I like to follow Derek’s advice on Mill City Roasters Youtube videos and mark Yellow when there are no more green beans. That’s probably later than you did? Just pointing out that as something to consider when you compare with other’s profiles.

Looking forward to hearing more about your roasts, especially how they taste.


  • Brad

Hey Brad!

Thank you so much for the tips and compliment.

I’ve lurked the forums enough to hold you in super high regard and I really appreciate you taking the time to reply and drop some wisdom :smiley:

I’m going to try your suggestions when I roast again tomorrow. I did feel like my RoR plateaued around my FC and I wanted to get it more smooth.

I’ve been meaning to check out more of the Mill City stuff, so I’ll do some late night watching tonight. I absolutely marked Yellow as soon as they started yellowing and not after they were all yellow.



Hey Andrew

@bradm brings up a good point in regards to when you’ve marked yellow. I wait until the bean mass is pretty much devoid of any hint of green before I call yellow. The exact time will vary depending on your green bean but an approximate figure bounces around the 164-170*C mark on the IRBS.

If it’s tasting great as French Press then that’s a good sign that you’re on the right track! Perhaps the apparent hollowness of your column drip isn’t a fault of the beans or the roast and a modification of your method may prove to improve your result?

Don’t get totally caught up in roasting to create a nice RoR curve. Your nose and tongue will tell you more than a RoR curve will. Data points like end temp, development ratio, time from yellow to first crack and turn around point are powerful when combined with cupping to help determine how you might modify your roast profile to achieve the flavours and textures you’re looking for. RoR curve is super handy when roasting as you can react to temperature change trends to keep the roast going to plan but it also useful for post roast analysis and I’d agree with your roast note beneath the chart, you may have dropped the power too early.

Which leads in to one final point - roast with a plan in mind. What coffee are you roasting and what are its inherent characteristics? What is its density? What brew method are you roasting for? What flavours are you looking to get out of it?

Just my 2 cents as a fellow novice roaster but I hope it’s useful.


Hey David,

Nice to meet you, and thank you for your advice!

I think you are definitely right about not obsessing over the RoR alone. I think at this stage in my learning about roasting it isn’t completely clear to me what effect my drop temp has beyond how “roasted” the coffee is, and I haven’t at all looked into the significance of the time between yellowing and FC. Those are some gaps in my knowledge I have to fill :slight_smile:

I’m hoping to get a good enough breadth of understanding so that I can roast with intent. Roasting for a universal brew like some of my favourite local roasters seems like a good goal, it’s just figuring out what specific changes need to be made based on origin, varietal, and bean characteristics. That’s even more learning that I need to do.

Thank you for giving me even more to research and some really good data points to learn about to improve my understanding :slight_smile:

These are my findings from attempting to follow the amazing advice here and some new book learnings.

My first attempt to put everything into practice resulted in this:

Which tastes excellent in the cup and very fruity. There is a bit of roasty taste that I think is from either the flick at 5min or the cliff at the end, but I am still too novice to figure it out. When I read Scott Rao’s book I noticed that most of his curves ended somewhere around an RoR of 3, so I attempted to get to around there. I am not sure if that’s misguided, or even if I’m doomed to be off because of the book being in F and me in C.

The second attempt was meant to be more like Brad’s suggestion of 207C and looked like this:

It doesn’t have any roasty taste, and doesn’t seem baked. It is extremely tea-like and tastes more like origin. I find it really pleasant and my family says it tastes like Red Rose Tea.

If you anyone has a chance to check my work, I’d really love the help. Thank you all for the suggestions so far and it’s been really great getting to know the folks on RoastWorld :smiley:

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Andrew I really like the numbers you’re hitting on both of those roasts. A nice amount of time between DE (drying phase end, or when we mark yellow) and FC. Perhaps the roasty taste in the first batch is from the 19% development ratio, which explains why your second batch, with a 14% dev ratio has that tea like quality without the roasty notes.

It would be interesting to replicate the first roast by creating a roast recipe off the roast profile but end the roast at 15-16% dev with your 206-208*C target end temp. Just a thought but keep in mind I’ve never done a filter roast before so my guidance is based off the theory I have read and other peoples filter roast profiles. My hands-on experience is in roasting for espresso. How would you go about it @bradm?

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Nice roasts Andrew. You made some pretty subtle changes, and it is encouraging to hear that you can already detect differences in the cup. That gives you good information to decide what fine tuning adjustments you’d like to make in the next attempts.

The F5 fan really quenched the roasts at the end, eh?

If these are Ethiopians, 13.7% weight loss may be too much to get bright acidity?

Tea-like flavor could also be underextraction. Does changing grind/brew process improve the flavors?

Although David’s right that recipes would work for fine tuning, I don’t bother with recipes, just use overlay. The way Matthew has the roaster settings displayed in overlay mode enables easy comparison for real-time fine tuning adjustments.

Please report how these roasts taste after about 7 days rest. I like to set some aside in a separate container so it stays sealed, not exposing it to fresh air every day. Hopefully one or the other will become a real winner.


Lots of amazing info in here and it just makes me more antsy to get my bullet…I ordered it on April 6th so I am just reading up as much as I can and trying to process all the information I can. I am super excited to experiment and find the “perfect” roast with the bullet!