The WORST batch size

As the title says it, I’m wondering if you all are finding you hate certain batch sizes than others?

I, for one, can’t seem to roast over 1lbs without overheating the boards, but find anything less to be only practical for sample batches and personal use.

But over time, I began to wonder, is 1lbs a good batch size for this roaster? One of the issues I seem to run into is the power stepping, where 10% jumps are very big, and often require work arounds. The stainless drum and power are very nimble, which is nice, but the settings for POWER and FAN are a bit of a frustration at 1lbs. F1.5, F2.5, and F3.5 would be an interesting options too.

Right now I am considering moving to a different batch size that is more conducive to the 10% paradigm. I see a lot of people like the 500g (a bit more weight, which may work with a power setting better than 1lbs batches)

And this is not a big batch vs small batch issue, in my mind. I really like some of the 200g batches I have done, and feel there can be a type of clarity to them. Though they are temperamental, and I generally feel a little more blind when roasting them. As environmental factors are more influential.

I like my testing with the 2lbs to 1Kg batches, but my machine absolutely cannot sustain the load without the boards underneath overheating. I’ve never had reliable results with P8 or P9 without the system auto shutting off mid batch. I have installed a fan underneath, and that allows me to temporarily use P9, or not have to worry about P7, but if the fan is any stronger, it seems to actually cool the roaster down a little. And all kinds of dust and coffee particle build up.

So, despite me loving how a 1lbs green batch turns into a 12oz bag with enough left over to sample, I’ve grown a little frustrated with how it feels like the power settings are either too strong or too weak by “5%”. But what to do with the extra beans on a 500g roast? Just roast darker? :wink:

Anyway, 1lbs has become one of my least favorite batch sizes, and I have begun experimenting with switching back and frothed between some settings, so that I can hit the right energy.

And for 200g batches, it is kind of love/hate. They can be some of the best and some of the worst. But because of the high highs, I still prefer them to the 1lbs.

Above 800g, and the power boards are the enemy.

But if any of you are liking the 2lbs or full 1Kg batch sizes in flavor better than 1lbs, or the same as you 500g batches, then i may figure out a better power board situation. I just hate pushing electronics to their limit. Wouldn’t mind the time savings though.

So, do you have a WORST batch size?

And for what it’s worth, when we roasted gas, and there was a 1% adjustment to the gas valve, we did often see that a 63% was sometimes better than a 65%, but nothing that couldn’t just be timed around. Only a nice convenience, if you missed a mark by a little, and really know the machine.

10% jumps in gas are pretty huge. You’d notice it on cast iron 60Kg batches, so this little stainless aillio thing, the jumps feel even more dramatic, since it can turn on a dime, so to speak. It is very agile. Agile, but not precise. I figure that weight is perhaps the work around, but have been using timing for the most part to acceptable results, and now trying oscillating P settings (which I hate increasing power after decreasing). But having seen so many mention they are doing 500g, I began to wonder if that is the perfect batch size for the power settings available? Why embrace the extra waste?

For what its worth, I like 800g preheated to 240° C

I usually make just a few adjustments during the roast (incrementally)

Start at P9, end at P6 or P5
Start at F2, end at F3 or F4
D8 or D9 throughout


Yes, that is incredibly helpful.

How do you use the 800g? Are you hobby roasting or packaging and selling?

I roast about 60kg a year; for myself and friends.

Start at P9, end at P6 or P5

Actually, looks like I typically start P8 for the 800g batches. This recent one came out well. A mexican washed bean:

There are way better roasters to follow on this site than me! People who are packaging and selling, as well.

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Unless there is an exchange of roasted beans, we just have to take someone else’s word for it. All experience in this case is really welcome! Roasting is a bit like sitting at a piano and having 88keys to do whatever you want with, and the options and preferences or moods make analysis a bit of a moving target at times.

I was going over some older threads, and it seems like 1lbs is too much moisture for F2, but not enough heat for F3 (loses heat)

1lbs @ F2 keeps the temps nice, but is a bit soupy. Idk, I’ve slowed the roast, and that improves some aspects, but loses the brighter flavors or sweetness (all subjectively)

1lbs @ F3 may (depending on the overall approach) and only may cause 1lbs batches to cool a couple degrees. Just depends on the overall trajectory.

This is not hard data, so much as personal anecdotal experience.

Anyway, I’ve been sort of kicking at the wind with this batch size and thought I could master it, but it never seems to work as reliably as I’d like.

Tried all sorts of charge temps, but 210C seems as good as any. With higher charge temps you have to slow it down. Sometimes a 2min “soak” just to get things on track. Such a coins in the dryer feeling. Haha.

I come from the 60-70kg probat back ground, so a lot of things don’t directly translate. So the idea is to find out how this thing excels rather than make it taste like something it is not, but yeah, sometimes

Ultimately, with all the tweaking I’ve done, I’d say the Munchow coffee mind is the way to go. But as you can see from the Sweet Marie’s video’s , there is no “one way”. It even defies Hoos and Rao in a sense… or at face value.

just have to take someone else’s word for it


So, better than Starbucks, apparently :wink:

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haha, that’s the dream!

You’re correct… there is no “one way” and roasting on the Bullet is just plain different from a Probat or anything like that. For me my sweet spot is actually 1kg batches. I find I get more consistent results with 1kg batches. I also have found that every bean being different needs adjustment as I go along on my roasting plan which is why I don’t use the automated recipe feature. I have a couple of written plan “template” (yes written on paper) that is my guide and I will adjust based on sight, sound and smell as I go along - e.g. I may adjust temp a little bit sooner for example.

As Damon said… take someone else’s word for it. I roast for friends (they pay me but this is not my bread and butter gig) and all of them have said it’s better than anything they get at the store.

I came from a FreshRoast SR500, then took a 2-day roasting class on a Probat 12kg years ago. While the Probat can’t translate to the Bullet but I think some of the theory can still apply. The thing with the Bullet, I find, is because it is electric based heat the response to temp change is a little delayed compared to gas source heat (not much different than cooking on electric stove vs. gas stove).

My suggestion is to stick with a batch size that you use consistently for a while, whether it’s 500g or whatever and tinker and document and keep cupping (I don’t know how long you’ve been roasting on the Bullet).

Happy Roasting!

I ran an experiment today and was able to roast 2lbs (900g) stable. I’ll try 1Kg some day soon, but I like how 900g divides into 12oz bags… at least for now.

Probat running half batches is a different beast from full batches (whether real or rated), and that is what the 1lbs (453g) and 200g batches feel like. With enough experience, the smaller batches come out really nice. Again, some of the 200g batches have been my favorites.

But having more fine control on the power would help. As I find with 1lbs, I’m occasionally wishing I had a .5 adjustment for power and fan. (Have not played with drum settings much).

In theory, if you can set up the machine to not kill the power to the heating element when using P9 and P8, and if you can do that reliably, then full size batches should roast the most regular and smooth. I notice people with 220v machines have less issues with full sized batches. 120v machines seem to run a lot hotter, and the safety mechanism kills it mid roast.

What fan setting/s do you use for 1Kg?

I was on F2 and put my hand near the exhaust port and it was like cigarette water vapor. Really wet and Smokey smelling. Pretty nasty stuff! Have yet to cup, but I don’t have high hopes. Haha

I also tried a few more approaches to 1lbs batches, and I feel like 500g sits with certain settings better. 350 was nice too. I liked it before I went to 1lbs. F2 works well and clean under 1lbs, and does not require any fuss. On 1lbs, F2 is a little humid, and F3 sort of sucks the energy a little and on some roasts, feels like it dries it out, or at least I get more crack lines. Could be other reasons.

But I’d caution people when starting out, maybe go with 500g to start, or 350g if you want to save on green. Below 350g and things are like down hill racing on a unicycle.

Unless we get .5 adjustments, then I feel like batch sizes will be pretty customizable.

I’m going to vote 500g as the best all rounder roast size. Might be worth standardizing batch sizes for sharing recipes.

1lbs (the worst)
1/2lbs or 226g
200g (sample size)

Are there other sizes that people frequently use?

I usually buy 5 lb bags of beans. I roast approx 565g per batch so that gives me 4 roasts per 5 lbs of greens. With about a 13% moisture loss a roasted batch last us a bit over 6 days.

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That’s sounds like a great way to go. Getting a slight discount per weight unit, and then working with minimal waste, while maximizing the potential of the roaster. Brilliant!

From Andrew Coe working with 500g batches, and many here adopting the 800g philosophy, that was popularized by an early article, the weight you’ve chosen seems like it could be great.

I’m not experienced enough with batches over 1lbs to know if there is a difference between roasting the different sizes, but I do notice a “stair stepping” of heat when switching between P settings, and some weights/densities/water seem to coast better than others. Like you can hit the P5 or whatever and hit FC softly but with enough energy, while other batch sizes feel temperamental and P5 feels too hot and P4 feels to timid. And pulling back too early causes a different flavor, or whatever is going on. Now, I’m not saying there are not work arounds…. I primarily roast 1lbs, but in terms of control, I feel like the holy grail is coordinating batch size to power intended power settings, but it can vary from bean to bean, so it is a lot nicer to have .5 Power controls.

I think what is so right about Andrew Coes template roast is that is gives the roaster room to modulate. I still don’t like the stair step, and a .5 would feather and smooth things better.

Anyway, this wasn’t supposed to be about the .5 settings upgrade. I’m using it to help describe my contempt for certain batch sizes. Haha.

To get “half steps”, maybe play with drum speed +/- 1.

Do you feel like that would do the same thing?

I’m just guessing.

From experience I know changing D affects the roast, but I don’t know if it’s exactly same as changing P by 0.5.

I’m thinking changing D by 1 would not be as significant as changing P or F. The air will be same temperature and speed, the drum will get the same amount of energy, but the beans bounce around a little differently.

The 220V Bullets definitely have more headroom for larger batches.

Have you considered getting a separate, battery-powered fan to force air over the IGBT transistors on the induction board? When I do 1kg roasts, that’s what I do, and that seems to work well. I think I might have listed what I got on the big thread where many of us were profiling full power 1kg roasts to 2C.

All that said, I prefer to do 455g roasts as I have the most practice making profile adjustments at that batch size, and I don’t have to fuss with extra gear for cooling.

Tech support told me in a recent message that the 220v and the 120v performed identically.