Convection Oven instead of Drum Roaster

[ezekiel]

I'm currently in the early planning stages of starting a small chocolate business and need to decide on a roaster.

Until today I was planning on building a drum roaster that could roast 20-25lbs of beans at a time. But, now I'm considering a commercial convection oven since it could be multipurpose.

What does everyone think of using a convection oven as a roaster? Also, how bad would it be to roast 50-100lbs of beans in one?

Thanks!
Ezekiel

[ezekiel]

After reading more through the forum it seems some are already doing this. So, how big of an oven would get me in the 25-35lb range per roast?

[Alchemist]

It is not uncommon. Mostly because it is something that you can do off the shelf on a large scale.

From my own small scale tests I prefer the taste of a drum roasted cocoa bean over a convection oven roasted one, but again, that is my preference and with limited hands on of convection ovens.

I personally love the idea of building your own 20-25 lb drum roaster. It is something I have considered myself.

The main issue I think you will come up against with 50-100 lbs at a time in any roaster is how much energy it can supply. You have to make sure not just that you can fit that many beans into the oven or roaster, but that you can get the beans up to temperature along the roast profile you want and that you are not just baking the beans.

[ezekiel]

I think I should clarify my question above. I don't need to roast the entire 50-100lbs at one time. I need a total of 50-100lbs. I don't, however, want the batch to be so small it takes 8 to 10 hours to have a total of 100lbs.

[holycacao]

I think it's worth it to build your own. The 20-35 lb range per roast is already a large drum roaster. We built one out of a dryer that roasted in that range. The roasts took about 45 minutes. There are a lot of ways to build drum roasters. Like John said, the crucial element to roasting is how much energy can be transferred to the beans. We bought a commmercial roaster in the end, so that we could have more control over the roasting curves and speed up the roast for some of our profiles. Our roaster has an output of 70000 btus. I don't know what the dryer had, but eventually we burnt through the flimsy sheet metal. I've seen on the web diy roasters that utilize stronger burners and believe that it is a doable project. Check Sweet Maria's for pics.
In general building your own (if you have the time) is the best way to learn IMO. It gives you the experience to know what features you really need/want.
All the best.
Jo

[ezekiel]

I am leaning heavily towards making my own. Here's my basic spec's as of today if I build one.

12kW electric heat

• 240V 60A circuit
  
• 12 - 1kW infrared heaters - www.grainger.com/Grainger/items/2LRT7
  

Stainless drum

• I'm thinking about using a large 100qt or larger stock pot for this.
  
• Should the drum be perforated?
  

Multiple temperature measurements

• Bean thermocouple
  
• atmosphere thermocouple
  
• drum thermocouple
  

Convection Fan

Variable Speed Drum

[Brad]

ezekiel;

You mentioned in your post that you are starting a chocolate business.....

The minute you make that transition, you go from "this would be a fun project just to see if it works" to "time is money".

Bill your time to EVERY project at $100 per hour. You'll quickly see that iin most cases t's simply not economical to "build things yourself".

Cooking anything is about heat and airflow. There is already a dual purpose piece of equipment out there that roasts cocoa beans and allows your business the flexibility of offering other products, such as baked goods etc. It's called a convection oven. Why reinvent it?

You can buy a second hand convection oven for less than a thousand bucks, plug it in, and start making money.

Conversely you can spend 20-30 hours tinkering with your home made version which does not guarantee you success, may very well void your shop insurance, and will cost you money for:
1. Parts
2. Time shopping for parts
3. construction
4. repairs (it will most likely require tinkering and repairs once up)

In the long run it's going to cost you around $4,000 to build something you can buy for $1,000.

The only exception I've been able to find in this industry is with a winnower. There is simply no inexpensive small scale equipment available that does what a cocoa bean winnower does.

I hope this makes some sense.

Best Regards
Brad

[ezekiel]

The dual use is my main reason for considering a convection oven. I have been pricing them and am not sure how big to go. I'm considering a dual stack since part of our future business will likely involve cookies, brownies, and such.

As you can tell, I'm still in early planning and thinking stages. As soon as I finish building the new house things will have to move much faster though.

[Brad]

Our convection oven holds 7 full sized baking sheets (16 1/2 X 26").

I roast about 5lbs per tray, and use all 7 slots in the oven. Beans turn out great.

On top of that, the oven is stackable. I can put one oven on top of the other, and beside each other, thereby allowing me to roast approximately 140lbs of beans every hour.

[ezekiel]

That sounds great. Especially since we are currently looking for a double stack oven to support the cookie side of things.

THANKS!!

[gordonschocolate]

I, like John, prefer the finished flavor of a drum roasted bean.
Though I have not experimented much with a convection oven.
Is there a commercial sized drum roaster available?
I would like to be able to roast at least 75lbs
per hour and probably more.
thanks,
gordon

[Brad]

Drum roasting, convection ovens, pizza ovens, home ovens, behmors, a wood stove, open fires, or a heat gun with a cookie sheet....

I've even heated hoagies and hot chocolate on the manifold of my jeep when I've been camping.

Regardless of what you use, it's all about heat and airflow.

The end result, if each medium is used correctly, will be exactly the same.

[ezekiel]

For a commercial roaster of that size, take a look at coffee roasters.