# Roast profiles on different roasters



## Stevebee (Jul 21, 2015)

I currently have been home roasting in a bread maker / heat gun roaster, with BT and ET probes linked via laptop to Artisan software. The bread machine is insulated and has a lid. The heat gun is fixed height with 10 variable temperatures.

Depending on the setting I can roast from 7 mins to 17 mins, each with a declining ROR. I can also extend any phase, drying, maillard or development I want by adjusting the gun but still maintaining a decline ROR.

The questions I have are these :-

1. Assuming I am not getting scorching or tipping (Can't see any) what is the best theoretical length of roast? (So far my best appear to be 11-12 mins but not sure why)

2. If I followed, say a drum profile, with regards to various milestones in temp and time, i.e. charge temp, drying end , first crack and drop, would the roasts be similar if the temperature and time profiles were the same.

3. I am looking at buying a 1kg capacity roaster on the assumption that the roasts will improve (and capacity) but I don't know why they would. If 80% of the roasting in a drum is via convection, and the BM/HG probably similar, how and why would the roasts differ to any great degree. The beans don't know where they are 

I know often the advice is that profiles on different machines can't be compared but if the measurable sabre so are similar I'd love to know why. When I started my roasting journey I never realised how complex, with so few hard and fast rules, it would be!

Steve


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## froggystyle (Oct 30, 2013)

Can you screen shot your profiles you are getting?


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## Stevebee (Jul 21, 2015)

Never tried inserting PDFs so hope these work

One is with no preheat the other with 170c preheat. I'll have to look back to see what heat settings I used. I think I was going for slightly quicker roasts.

Both dropped around 215c. Now I am roasting c 11:00, dropping at 210-212. My Amprobe connection to Artisan is intermittantly cutting out which screws up the graph so I monitor key points along the way. Once I hit 1C, I use a table that shows what time to drop for 20% development and what time for 25%, so I normally go between these points as I mainly roast for brewed.


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## froggystyle (Oct 30, 2013)

Is your temp probe inserted into the bean mass, or at least for half the time does it go into the bean mass when roasting?

From your comments i think you might be roasting to fast and ending to early, maybe try to get upto 215-220 in 10-12 minutes and hold it, or holding it at first crack.

Just because beans look finished on the surface they might not be inside.

You dont want to be dropping the roast temp at the end, this needs to remain stable, drop when you think they are ready and cool ASAP.


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## Stevebee (Jul 21, 2015)

Probe is in the green bean mass from the start via a hole drilled through the side of the BM about 2/3 cm from bottom , about 4/5 cm in. I can see through a viewing hole that it's submerged all the time.

I'm ending based on temp. When I roast to 220 the colour is darker than I like for brewed. I tend to then use those for espresso. 2nd crack is about 225 for me.

Most of mine are pulled just passed end of first crack. The reason I sometimes get a small drop is if I overdo dropping the temp to achieve a temp of 210 AND at least 20% development. To achieve this the ROR can be small. Now I leave the temp reduction a little longer past 1C as it seems to pick up again about 5c past first crack so this is when I back

off.

When I have cut the beans they look the same throughout as far as I can see.

To cool them I use a pasta strainer inserted in the lid if a bucket. A toilet overflow valve is cut into the bottom side of the bucket and a vacuum cleaner used to create the airflow. The beans go from drop temp to ambient in about 1m 30s

I roast 300g batches.

Any thoughts if I replicated a longer drum profile of say 13mins, would they in principle be similar roasts


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## froggystyle (Oct 30, 2013)

Sorry should have said, get it up to 205-210 and hold it there.

On the Gene i roast around 13 to 15 minutes depending on the bean, and the level of roast i want from it.


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## Stevebee (Jul 21, 2015)

That's basically what I aim for. At 205 I reduce the heat slightly otherwise the ROR will take it to 210 too quickly. I aim for at least 20% development (a nod to Mr Rao). It's a juggle to get this without stalling. If I dropped at more than 210 it's a lot easier but my main roasts are for brew and I prefer the earlier drop.

Can the Gene be pushed to do say 8 min roasts or is the 13 - 15 mins where it tends to be more comfortable. I have never used one.


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## froggystyle (Oct 30, 2013)

I don't think you can get the gene upto the temps required in 8 minutes, usually I am at 175c in that time.

The good thing about it is having two heaters, you can knock one off at 215 and hold the temp for a couple of minutes, this I find critical in finishing the roast off.


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