Table-top Conching Machine??

Replies to This Discussion

Permalink Reply by Tom on August 3, 2009 at 8:22pm

I had my Spectra 10 motor refurbished and replaced the belt on mine when I noticed a similar slowing of the spinning bowl. Works like a dream now. Belt was just matched at a local bearing shop. You could also look at washing machine belts - I did but couldn't find an easy match. It is good to know a bit more about the Ultra's insides and its issues as I was favouring the Ultra for my next grinder because of the top down clamping. As for increasing the capacity. I know Brad modified his Spectra 10 by discarding everything except the motor, mounting and the granite rollers. He welded together a top down clamp for his granite rollers and tossed the stone drum and used a heavy steel based pot. The pot just from my eyeballing it looked slightly bigger than the Spectra bowl so I would estimate it could hold perhaps 1-2 more kg than the spectra 10 bringing it up to 4-5 kg from 3 kg max in the Spectra 10.

Permalink Reply by Frank Schmidt on August 6, 2009 at 4:18pm

It would be a very small market, don't you think, Clay? How many home/small scale chocolate roasters are there in North America? But then, there may be some other similar market where the milling machine would be useable. I have a feeling that your ball mill, if priced near the same as a counter top wet grinder, would be competitive. Sounds like it would be purpose made for chocolate instead of "adapted" from another use the way wet grinders are.

I'd like to see photos or vids of the concept.

Permalink Reply by Clay Gordon on August 6, 2009 at 5:35pm

I am searching for the short video that is attached to this preview photo.

You can only see the pulley from the drive unit (the pulley is attached to a shaft welded to the bottom of the mixer bowl). The frame can be easily made using a variety of materials and as you can see the "bearings" are simple casters and you don't even need to remove the handles from the bowl. You can attach fins or vanes to the inside to improve tumbling performance (this bowl has them, you can barely see one in the 1:00 position - and it's okay to use dented and dimpled bowls).

The heat source is a small gas burner set below the unit. The blue hose is the propane supply.

Grind nibs into liquor and fill the unit with stainless steel ball bearings and you have a primitive but effective ball mill. You can add heat via the burner (bad idea) or you could use a heat gun or light bulb and fan. Blowing warm air into the bowl would speed things up. When done, pour the finished chocolate through a magnetized grid made from fine-mesh steel.

You can pick up a 60qt used Hobart bowl for under $100 on eBay. I think you could make a 50lb (liquor capacity) machine with used and spare parts for about $500.

Right now there's a 30qt bowl on eBay for $59 so you could probably build a 30lb (liquor capacity) machine for about $300. Is that price-competitive enough?

BTW. This unit was in use in the Tulicorp factory in Guayaquil, Ecuador. They were using it as their small "test batch" roaster.

Permalink Reply by Tom on August 6, 2009 at 9:59pm

The ball mill is intriguing. Is the bowl steel or aluminium? Do you know details like timeframe for refining, optimal number of steel balls required for certain amount of chocolate? Do you think the friction would maintain molten chocolate alone once it got up to temp?

Permalink Reply by Clay Gordon on August 7, 2009 at 12:03pm

I am not sure about the answers to any of these questions as I have never made one. I do know that Terry Richardson of Richardson Research makes lab-size versions and I have seen one in use in a class by Peter Greweling at the CIA in Hyde Park, NY.

Friction may be enough, but you'd probably want to blow warm air into this to increase the evaporation of undesirable volatile aromatics. I will try to get in touch with Peter to see if there are any guidelines he can share.

Capacity is dependent not only on the volume of the bowl but the angle that bowl is tilted up from horizontal. The steeper the pitch the greater the capacity.

Timeframe is overnight -12 hours - at least. Keep in mind that the particle size distribution of a ball mill like this is likely to be broad around the peak and have some peaks in both tails.

Permalink Reply by Nancy Nadel on January 22, 2010 at 1:53am

Terry Richardson had the ball mill in the class I took at Davis and I attached some pix but I don't recall the number of balls. I recall and the picture attests to an attached hair dryer for heat. We ran it in class for at least 24 hours.

Attachments:

• chocolatetechnology 035.jpg, 436 KB
• adding balls to the ball mill.jpg, 429 KB
• chocolatetechnology 038.jpg, 430 KB

Permalink Reply by Robert Osgood on January 4, 2010 at 3:40pm

Has anyone used this concept to roast coffee? I use an alluminum cage mounted on a rotiserie and attached to the propane-fired barbe, which works great for 1 kg batches of cacao beans. It also roasts 0.6 kg batches of coffee although at at a higher temperature.

Permalink Reply by Frank Schmidt on August 7, 2009 at 11:53am

Must they be steel balls? How many do you think would be needed? A dozen? Hundreds? Could ceramic balls work? http://www.vxb.com/page/bearings/CTGY/Loose-Ceramic-Balls

Don't want to complicate things but just wondering.

Permalink Reply by Clay Gordon on August 7, 2009 at 12:08pm

I think it may be technically possible - but it's not workable from a food safety perspective.

If a ceramic ball bearing chips you won't be able to retrieve the shard (likely very sharp) from the liquid chocolate because it's not magnetic and the density difference between the ceramic material and the chocolate is likely not great enough to make it reliably sink to the bottom or float to the top so it can be removed. Any mesh screen small enough to trap a chip is likely too small to let the chocolate flow through easily unless it's very, very, very fluid.

With bearings made from a material that is attracted by magnets you can reliably remove any sharp bits that break off.

Permalink Reply by Ezekiel Holliday on August 18, 2009 at 2:41pm

I've been looking to building a ball mill for producing cocoa liquor. From the research I've done, to mill 1 liter of liquor you need 1 liter of balls. This is where building a mill gets pricey. Media runs from about $12.90/kg for chrome steel to $30.62/kg for stainless steel. So, if you would like to mill 5kg of cocoa your going to need approximately 24kg of media. That comes to $310 just for grinding media.

Does this rule out building a ball mill? I don't think so. Ball mills have some great benefits for particle reduction. And, I don't think it would be hard to build a very reliable ball mill of that size or even somewhat larger.

On the other hand, I don't think building a reliable stone melangeur like the Santha would be that difficult either. The biggest question I have would be where to get the stones.

Permalink Reply by ramya on April 25, 2012 at 11:57pm

for a  ball mill it is better to use ceramic balls instead of steel balls.

Permalink Reply by Frank Schmidt on August 19, 2009 at 10:13am

Question for all who are reading this thread.....why must the volume of milling media (steel balls) equal the volume of material being milled? Is not time a factor here? Could we not substitute longer milling time for the quantity of media?

I have not used a ball mill before. Why not use half or one third the volume of media and lengthen the milling time appropriately? Am I missing something?

• ‹ Previous
• 1
• 2
• 3
• Next ›
• Page