DreamRoast 1kg+ Coffee Roaster [now built]

[farmroast]

I've been working on a hybrid 1kg roaster for about a year(not the one in my pic). Been trying to think outside the drum so to speak. It's not a drum type or fluid bed. Bean agitation is adjustable and is done mechanically. It uses fast reacting electric heat with convection. Am building in lots of adjustable controls. The latest test prototype is about finished. Please, challenge my engineering abilities. I want to be sure it has all the capabilities the most demanding Roaster would want. Tell me what is most important to you for basics and special features. Would also help to hear shortcomings of existing 1kg roasters. thanks, Ed

[OkcEspresso]

I am rooting for you!

Basics:

- Sight glass
- Tryer
- T/C in the bean mass
- Ability to control temperature and ramp speed
- Internal light


Advanced:

- Internal chaff removal
- Multiple t/c's for sampling air temp both in bean mass and near heat source (or air flow)
- Ability to repeat roasts automatically (process control)
- Bean cooler

[Rainman]

I am rooting for you!

Basics:

- Sight glass
- Tryer
- T/C in the bean mass
- Ability to control temperature and ramp speed
- Internal light


Advanced:

- Internal chaff removal
- Multiple t/c's for sampling air temp both in bean mass and near heat source (or air flow)
- Ability to repeat roasts automatically (process control)
- Bean cooler

That pretty much covers it- maybe add in a good method of agitation?

I'm rooting for you, too!

Ray

[farmroast]

I am rooting for you!

Basics:

- Sight glass
- Tryer
- T/C in the bean mass
- Ability to control temperature and ramp speed
- Internal light


Advanced:

- Internal chaff removal
- Multiple t/c's for sampling air temp both in bean mass and near heat source (or air flow)
- Ability to repeat roasts automatically (process control)
- Bean cooler

Sight glass -- yes
Tryer -- still working on design, want it to be able to pull a few and return and pull an amount to keep out for testing(what would the ideal amount or range for this feature?)
T/C bean temp--- yes, and quite accurate and fast reacting
Ability to control temp and ramp speed-- yes Main heat with fast reacting control W/PID and separate boost heater.
Internal light --- No But good idea, will add with proper spectrum
Internal chaff removal---- Chaff is removed as produced from the roast environment completely.
Multi t/c --- Yes one measures air temp the other bean external temp
process control repeatable---- Yes with PID (how much desire for computer connect?)
Bean Cooler---- Yes cools to room temp in about a min. or so. (2lb.) batch


Also, roasts in a low oxygen environment to limit oxidation of bean surface( no flow through air used)
Low energy usage
Super bean agitation for very even roasts.
Adjustable convection

[OkcEspresso]

I dont think the tryer has to pull a lot of beans if you can pull it multiple times to get enough to grind and brew. Now if it would pull exactly 7 grams that would, of course, be ideal.

Ability to interface a PC is a great idea to log or even control profile.

I forgot to add that I would like the price to be under $100 !

[Niko]

I forgot to add that I would like the price to be under $100 !

[Branden]

When will the prototype be unveiled?

Branden

[farmroast]

When will the prototype be unveiled?

Branden

I'm planning to put up a thread in about 2-3 weeks on homeroasters.org for their homebuilt roaster contest and will put up a post on here too. My first intent has been to see if I could create a 1kg roaster for myself and then possibly for other serious homeroasters who wanted a larger batch size and without the limitations of idiotproofing that must be designed into mass marketed kitchen counter home units. I feel this unit might also have small shop, sample batch, etc. applications too. Sadly,production is not easy in the US anymore and since this is not a high volume mass market product I will probably attempt to reproduce a few in my and a neighbors farm shop and go from there. Ed

[OkcEspresso]

What do you think the cost/price range will be?

[farmroast]

What do you think the cost/price range will be?

Depending on options and controls desired been aiming at a 1200.- 2500. range.

[OkcEspresso]

Depending on options and controls desired been aiming at a 1200.- 2500. range.

Still rooting for you!

[Branden]

Will there be any form of air-flow control?

Branden

[farmroast]

Will there be any form of air-flow control?

Branden

There is a variable speed convection fan. But no in out new air flow. I find no value in bring in and exhausting oxygen. Drum roasters use it to remove chaff and of course to keep the flame going, temp. adjust. fluid bed to keep the beans floating and transfer the heat. Less oxygen in roasting chamber keeps smoke level and oxidation at a minimum. Thanks again for the questions, Ed

[DaveC]

It's not a drum type or fluid bed. Bean agitation is adjustable and is done mechanically. It uses fast reacting electric heat with convection. Am building in lots of adjustable controls. The latest test prototype is about finished. Please, challenge my engineering abilities. I want to be sure it has all the capabilities the most demanding Roaster would want. Tell me what is most important to you for basics and special features. Would also help to hear shortcomings of existing 1kg roasters. thanks, Ed

It would help to have a little more explanation of the design and how it's working, because viewing the suggestions you have just about every suggestion under the sun, some of which may not be relevant due to design.

Basics:

Easy and quick to get the beans out of the roaster and the next batch in
Ability to vent the smoke
Some thought in the design about power failure just at the end of a dark roast and fire avoidance
Trier
Thermostat and heat control
Quiet operation so the cracks can be heard
design that is easy to maintain/clean the bits that will get dirty

There is a variable speed convection fan. But no in out new air flow. I find no value in bring in and exhausting oxygen. Drum roasters use it to remove chaff and of course to keep the flame going, temp. adjust. fluid bed to keep the beans floating and transfer the heat. Less oxygen in roasting chamber keeps smoke level and oxidation at a minimum. Thanks again for the questions, Ed

Probat had a setting caller Aromaroast on their older gas roasters.......this was to stop the airflow in the drum and effectively cause the beans to "braise" in their own smoke. This function was/is used in the last minute or so of a roast and is commonly used to disguise the taste of cheap coffee and give it a "better" aroma. It's actually not very good for the coffee though and is rarely used. It could be that not introducing some minimal in/out airflow into the roaster might be a bad idea? I don't know if you have already experimented with this and cupped the results...especially at darker roast levels.

[farmroast]

Probat had a setting caller Aromaroast on their older gas roasters.......this was to stop the airflow in the drum and effectively cause the beans to "braise" in their own smoke. This function was/is used in the last minute or so of a roast and is commonly used to dusguide the taste of cheap coffee and give it a "better" aroma. It's actually not very good for the coffee though and is rarely used. It could be that not introducing some minimal in/out airflow into the roaster might be a bad idea? I don't know if you have already experimented with this and cupped the results...especially at darker roast levels.

Interesting. I have no experience with a drum roaster. If you looked into the drum with this setting would actually see smoke? or is it more of a dense combination of the roast and burner a bit of charred chaff exhausts. With mine there is no visible smoke in chamber (have not done a roast past a vienna solid rolling 2nd crack) but yes the roasting aromas, gases,etc. do stay contained and with the electric element there are no burner exhausts. What was the bad effect that could be found in the cup when the "Aromaroast" setting was used on a good coffee? thanks, Ed

[DaveC]

Aromaroast simply gave the coffee smell and a flavour that disguised it's true nature....so a good coffee would not show it's characteristics well. In the 25kg Probat I used, you couldn't really see inside the drum, because although it had a sight glass and trier hole....the site glass is covered with roasting beans pressed up against the glass and the trier hole is relatively inaccessible, but you wouldn't see much in there anyway as it's dark.

I do think having no airflow....is asking for trouble in terms of taste, especially at darker roasts.

[Alchemist]

What stage of construction are you in? I get the impression that you have actually built and tested concepts here. I was wondering if you have actually roasted 1 kg of beans with all the smoke contained. Even without environmental oxygen, there is plenty of oxygen the beans to smoke in my experience.

What comes to mind is if you do have outside airflow at some point (dream roaster mind you) then some ilk of afterburner to deal wish smoke would be great.

Are you working at 110 v/15 A? What power consumption?

If you have a good trier then I think a good external mounted light would be better than an internal one. Also, a built in timer. Minor stuff here mainly.

Ease of dumping beans without the need of gloves.

Easy cleaning of chaff and viewing glass (if there).

Two TC. One in the bean mass, one in the ambient "air".

[farmroast]

What stage of construction are you in? I get the impression that you have actually built and tested concepts here. I was wondering if you have actually roasted 1 kg of beans with all the smoke contained. Even without environmental oxygen, there is plenty of oxygen the beans to smoke in my experience.

What comes to mind is if you do have outside airflow at some point (dream roaster mind you) then some ilk of afterburner to deal wish smoke would be great.

Are you working at 110 v/15 A? What power consumption?

If you have a good trier then I think a good external mounted light would be better than an internal one. Also, a built in timer. Minor stuff here mainly.

Ease of dumping beans without the need of gloves.

Easy cleaning of chaff and viewing glass (if there).

Two TC. One in the bean mass, one in the ambient "air".

Unit is being tested as I go along. did a 2# batch to fc+ easily in 16mins. Considering batch size not much smoke is apparent(none visible in chamber just some out my chaff collector and aroma vent, til batch is dumped and is exposed to the air. but smoke, for me, is only a concern having to do with roast quality. Not going to even try to make a "smokeless" for the kitchen counter roaster. Am working on venting so it could be used indoors if one is not to picky about some roast odors. Your afterburner mention is being considered if needed after more test roasting and cuppings are done.
110v but been plugging into 2 different circuits presently. The main heater with variac using 12-13+ amps. plugged directly into one outlet. The other stuff, motors, fans, boost-large batch supplemental heater on a 12ga cord to separate circuit outlet. Without using the extra heater it might all work on a 15a line or certainly a 20a. Will have to do more test with my Kill A Watt meter measure each component usage.
I'm leaning towards your thoughts with the trier external light. And if I goose neck it could shine inside well enough too.
Two TC's ,check--love it. measures air temp just before it hits beans and bean mass.
chaff collects in an external canister that is just dumped.
been waiting on a couple pieces of metal to arrive. pics should be ready in about a week of the tester prototype. John thanks for your thoughts, Ed ps am thinking about sending out samples of fresh roasted batches with roast date to those interested, to cup.

[farmroast]

What is the number of beans you want to be in a trier to view and smell? mending fences and working on the roaster. life on the farm is good, thanks again for your thoughts, Ed

[Alchemist]

Quite a bit of power there.

From experience of my own roaster, 20 amps is enough to do 40 oz of green beans to 2nd within 17 minutes.

Also, as far as a suggestions goes that is unrelated to specs or wishes, how is your insulation level? Again from my own system, I have found it is the most under appreciated aspect of design currently and often the one with the most effect IMO.

PM me if you would care to talk about insulation etc. I have been doing a bit of research lately for my next roaster project.