# Oven roasting - as unwise as that may be



## ajohn (Sep 23, 2017)

I'm thinking of trying to roast beans in a rotisserie. Temperature control and a rotating drum. I've looked around on the theory etc but without adding other bits and pieces not really pertinent at the moment.

So looked around the web on roasting this way. Info was infuriating in some ways as it often is. One site mentioned the same as most do, set a temp and then do it etc but also using 2 temperature, low and then high to slow things down = better roast - no numbers though. I've seen that comment on one small home roaster as well. A phase where the beans expand and get lighter.

I can only guess but would suspect that the lower temperature would be the yellowing point and the higher a normal roasting temperature. I could use the oven to slow the roasting down by starting from cold but using 2 temperatures sounds like a better idea with more control. I have tried with a popcorn roaster and found that heat went in too quickly tending to result in no real expansion and burnt beans.

So on that basis what would a likely yellowing temperature be - actual bean temperature? Roasting proper seems to be of the order of 230C. ??

John

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## Batian (Oct 23, 2017)

This should sort you out. There is also loads of info on DIY roasters within the site.

https://legacy.sweetmarias.com/library/content/using-sight-determine-degree-roast

The old version:http://legacy.sweetmarias.com/roasted.pict-guide.php

http://legacy.sweetmarias.com/roasted.pict-guide.php


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## ajohn (Sep 23, 2017)

Thanks for reminding me of that site. I've found it useful in the past. I went to the old version and found what I was after immediately. I'll try the new later.

John

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## Rob1 (Apr 9, 2015)

High is the first setting and low is the second setting. I wouldn't think you'd wait for the beans to yellow (~170c bean temp) and then increase the heat.


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## ajohn (Sep 23, 2017)

I honestly don't know. The reason for thinking low then high is that I have no idea how quickly heat will get to the beans. I played with a popcorn machine and on that I suspect heat was going in far too quickly resulting in burnt beans and 1st crack. I wondered about adding temperature control but it wont hold what I see as an ideal weight to roast - about 500g out- so not worth the effort.

I've no idea how quickly heat will go into the beans in a mini over or the best way to go. So first try set some temperature and preheat the oven then put the drum in and watch colour - or don't preheat and do the same. Then at the time they show the colour go to full temperature.

The Behmoor seems to use power into the heating. The mini oven a thermostat. I assume the idea is to heat the beans evenly even internally so starting from cold makes most sense. Past that point pass.







I have 1 kg of beans to play with and the person in China reckons the drum is ok for 250g. I also have some cheap robusta beans left from trying with the popcorn roaster.

The link that was posted suggests that 150C might be a decent initial temperature - browning. Then pass but maybe 240C if I want oily beans or a suitable temperature for 1st crack, 180C, then higher. It may not reach 240C but a quick play before roasting a chicken suggests it will. A tutorial on manual roasting with the Behmoor suggests slowing stages down by reducing heater power.

The Behmoor might be well insulated. These mini ovens aren't. The casings get way to hot to touch. I've no idea how temperature fluctuates due to it's thermostat either but can stick and oven thermometer in. I get the impression due to weight that the professional roasters maintain a pretty stable temperature but could be completely wrong.








Biggest other problem is messing up the oven - my wife likes the chicken it produces. I do too. II suspect it will do a good job on a rolled pork joint as well.

If it gets messy inside I'll have to clean it up. If it works out maybe buy another cheaper one and modify it a bit.

John

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## Batian (Oct 23, 2017)

How about an oven thermometer ? Then try and regulate the temperature by turning the heat up/down/off.


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## Rob1 (Apr 9, 2015)

I'm not familiar with how your oven works but if it's closed and airflow is designed to maintain a set temp then setting your oven to 150c will not get you to browning. It will get you (eventually) to the point where the beans dry and pale.

180c won't get you to first crack it will get you to browning and I imagine if you get to that stage and then increase the heat you'll end up taking a long time to get from there to first crack.

I'd set it to 240c, preheat, put the beans in and see what happens. See how quickly the roast progresses noting the time as the beans change colour and make adjustments from there. You might want to drop the heat on yellowing or browning, or maybe even first crack depending on how quickly you get to each stage.


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## ajohn (Sep 23, 2017)

Rob1 said:


> I'm not familiar with how your oven works but if it's closed and airflow is designed to maintain a set temp then setting your oven to 150c will not get you to browning. It will get you (eventually) to the point where the beans dry and pale.
> 
> 180c won't get you to first crack it will get you to browning and I imagine if you get to that stage and then increase the heat you'll end up taking a long time to get from there to first crack.
> 
> I'd set it to 240c, preheat, put the beans in and see what happens. See how quickly the roast progresses noting the time as the beans change colour and make adjustments from there. You might want to drop the heat on yellowing or browning, or maybe even first crack depending on how quickly you get to each stage.


You could be correct. I quoted temperatures from the link posted early on. Heating is radiation / convection. 2 bars in the top and 2 bars at the bottom. It heats up pretty quickly but I can't quote times. 1.5kw oven. I can try several things. I bought some robusta to destroy and maybe try if the roast looks ok. The popcorn roaster didn't work out well at all. The beans didn't get lighter as they should even after altering the quantities. The type that swirls them around on a hot plate didn't either - tended to provide a lot of one sided heating. I sent that one back.








I like to leap in and see what happens and then refine so flat out could be the first try but I think I'd be inclined to start that from cold. I had intended to aim to be a bit short of first crack and then increase and see what happens. That based on the Behmoor tutorial where he slows it down at 1st crack to even things out.

There are now a couple of drum sizes available that should fit directly on the rotisserie spits in some mini ovens. The larger one may take the quantity of beans I'd ideally want. Other than adding a better thermostat if needed they would be very easy to modify. I get impression that the hysteresis on the thermostat in them is pretty large having seen 250C with a meat thermometer. It should only go up to 230C. It did a rather good chicken but needed setting higher on the dial to get the right temperature so looks like it's a bit none linear as well.

John

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## soundklinik (May 31, 2013)

I Completely moded a grill into a roaster. Changed the motor to 60rpm, insulated it with special thick wool like material held in place with sticky aluminium tape 2" wide.

Even the window on top is covered with this stuff to keep heat in.

I added PID because the thermal control stopped @230 Celsius

The problem is there are only 2 elements and I can't find additional ones which means the roasting capacity is rather small, around 150 grams. Otherwise it works great.

if anyone is interested I will post a few pictures.


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## GingerBen (Sep 7, 2017)

quite a few people on a US bbq group I follow on linked in roast beans in their kamado grills using a rotisserie. They just eyeball it but seem happy with the results.


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