Profile for 680g Batch

I just got my bullet and I’ve roasted a few 350g batches that have turned out fairly well. I tried roasting a 680g batch yesterday and it was terrible. I hit 15:00 and first crack hadn’t even happened yet. Those of you who roast this size of batches, what heat setting do you start on? I started with P7 and I’m guessing that was not high enough. I’m struggling to nail down a profile for this size of a batch! Any profile tips?

This is nothing but personal opinion from someone that roasts with an odd profile (heat soak). Just a couple very general things-

  • expect to go thru some greens making the journey from newby to seasoned. That road is littered with roasts that were less than expected & then discarded. “Next time” is ok!
  • I believe you’re right that more power will shorten the total time. So too will reducing Fan speed and maintaining P7 longer. It’s a balancing act. Since it’s all about the beans you’ll have to experiment.
  • from the temps I see I believe you may have ended the roast about the start of 1C so development time is very limited. That may be your plan but… ??

You can scan thru roasts by going to your Dashboard → Users then either randomly pick a User and look thru roasts or if you have someone in mind then enter their User Name. For instance I went to Dashboard → Users and entered strausal24opu to find the 2 roasts you have in your Roast History.

Alternately you can go to Dashboard → Beans → Discover and enter e.g. Origin = Guatemala, Bean Name Xinabajul and select one of the hits and explore the roasts that pop up. Here’s one that is (kinda) similar to yours in duration & power but a larger batch. R.W can be very helpful in this regard.


To add to what Bruce said, you can also search R.W. based on batch sizes. 680g is an odd number, so maybe try 500g or 750g or 800g. I took a quick peek at your 680g roast. I think you dropped power too soon. FWIW, my 500g I actually increase power to P8 from initial P6 or P7. Here’s an example of one of my recent 1lb (thus the odd 466g) for a Guatemala.

Thanks for the input! I did stop the roast because I thought it had already been too long of a roast to salvage, and I got frustrated and just kind of quit. I will definitely check out the search feature a bit more and see if I can find some similar profiles. It has felt like a shot in the dark to figure out decent working profiles so far. Hopefully some more experimenting and I’ll be on my way.

Thanks for the input. Do you think I could have started with P7 still if I just didn’t drop the heat so soon, or should I have started somewhere around P8 or 9? I went with 680g because I was reading somewhere that it’s best to roast at 2/3 your roaster’s capacity, and that also comes out to two 12 oz bags. Foolishly didn’t consider the fact that the weight changes pretty drastically after roasting. I will probably try a 750g roast next!

You start with a higher PH temp than I do, so starting with a P7 or even P6 should be fine so that you don’t scorch the beans, but you might then want to increase the P level by 1 or 2 to keep the roasting momentum going at around the turning point (usually around 1 to 1-1/2 mins into the roast) because the beans would have soaked up the initial heat without scorching. After that as you approach yellow point or after you might then start to lower P and increase F, etc.

I do highly recommend looking at other people’s profiles for around the green weight you want to roast to get some ideas. There are “established” techniques (ppl on these forums will reference Scott Roa’s books a lot) and then the more “contrarian” ones like the “heat soak” technique that Bruce mentioned. I also recommend doing more at 350g to learn the nuance of the Bullet and roasting on this machine, how the different settings, P/D/F, changes the profile and affects the end results.

FWIW, when I started on the Bullet a year ago I referenced a lot of bradm’s 350g profiles to get a feel for this machine (I came from a FreshRoast SR500). I then started to look up 500g and 750g profiles to reference but I ended up extrapolating a little from 350g profile from bradm and what I had liked of my own to get to my own 500g. For 1kg profiles I referenced cash0216’s profiles.

Roasted bean weight will highly depend on how dark you roast. The darker you roast the weight loss is higher since you’re “burning” off the moisture.

In my view, there is no “one right answer” … just what you like when you cup it.

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Thanks! I tried increasing the heat at turning point and decreasing at yellowing, and tonight’s roast was a huge improvement. Still not where I want it by any means but I’m getting closer. I want first crack to be earlier next time and I want to shoot for a longer DTR (around 20% maybe?). I also think I jumped the gun on identifying the yellowing stage. I will definitely be incorporating these tips in future roasts.