Our Valued Sponsor
OpinionsConsumer ReviewsGuides and How TosCoffeeGeek ReviewsResourcesForums
Coffee: Home Roasting Talk
Custom Roaster Wishlist
Donate to Coffee Kids
Coffee Kids works with farming communities around the world, improving lives. Donate today.
www.coffeekids.org
 
Not Logged in: Log In to Postlog in
New Topics updated topics   New Posts new posts   Unanswered Posts new unanswered  
Search Discussion Board search   Discussion Board FAQ faq   Signup sign up  
Discussions > Coffee > Home Roast > Custom Roaster...  
view previous topic | view next topic | view all topics
showing page 2 of 2 first page previous page
Author Messages
wcmocha
Senior Member
wcmocha
Joined: 26 Dec 2010
Posts: 218
Location: Colorado
Expertise: I love coffee

Espresso: Gaggia Classic
Grinder: Nemox Lux
Drip: Keurig
Posted Fri Apr 12, 2013, 12:19pm
Subject: Re: Custom Roaster Wishlist
 

I just bought a bake-a-round last night and it already shipped, so I'll be using that for the tube.  I've got 10 pounds of green beans on their way too so it's coming together and I'm excited.  Some good info here, thanks for sharing.  Have you measured the air flow over your flow rate changes?  I'm curious how much of a velocity change you are getting from adding recycled air in your system.  If so is that your goal or is it more for efficiency with the hot air?

My thought is that the velocity/volume is adjusted to a level that efficiently rotates the beans through the heat, but I'm wondering if there is a benefit to changing that variable during the roast.

Now you've got me wanting to rig up an IR sensor to play with when it's done.  That could be cool.  I've heard people say that with hot air you're roasting to a temperature more than a color.  True or not, It got me wondering if after a successfully documented roast you could duplicate it using a computer and temperature readings?
back to top
 View Profile Link to this post
oldgearhead
Senior Member
oldgearhead
Joined: 25 Jan 2010
Posts: 395
Location: Go Colts!
Expertise: I like coffee

Grinder: Virtuoso by Baratza
Drip: Chemex,Dilongi DCM900
Roaster: 1/2K Fluid-bed
Posted Fri Apr 12, 2013, 4:52pm
Subject: Re: Custom Roaster Wishlist
 

I'm recycling RC air to increase heating efficiency. I recycle most of it during the 'ramp to first crack' phase when the highest RoR (rate of rise) is required.

I think l mentioned I was using an Ametek/Lamb 5.7", two-stage, flow-thru vacuum/blower. I use a single-board DC drive to control it. The drive is set for:
1) One horsepower
2) Min speed 20V
3) Max speed 70V
4) Torque 60%

During today's 440 gram roast the voltages were;
1) Start - 38V
2) T=3:00 min - 25V
3) T=6:00 min - 18V
4) Cooling - 70V

The vac/blower has a max flow of 100 cfm and a max pressure of 100 in/H2O (not at the same time...)

Because coffee cherries lose 15-20% of their weight during roasting, I lower the air flow a couple of times during a roast to retain heat in the bean mass.
However, I'm using a 550F heat source, if you are using a big gas burner you may need to do the opposite.
back to top
 View Profile Link to this post
wcmocha
Senior Member
wcmocha
Joined: 26 Dec 2010
Posts: 218
Location: Colorado
Expertise: I love coffee

Espresso: Gaggia Classic
Grinder: Nemox Lux
Drip: Keurig
Posted Fri Apr 12, 2013, 6:35pm
Subject: Re: Custom Roaster Wishlist
 

Thanks, I'm looking at some blower options I have at my shop so I can save a few bucks and that gives me a ballpark.  Changing the flow as the bean weight changes makes total sense.
back to top
 View Profile Link to this post
jkoll42
Senior Member


Joined: 2 Jan 2010
Posts: 465
Location: Pennsylvania
Expertise: I love coffee

Espresso: VBM DD V3, Gaggia Baby Class
Grinder: Cimbali Max Hybrid, Bunn...
Drip: Technivorm, Chemex
Roaster: Honey Badger 1K, HG/BM
Posted Sat Apr 13, 2013, 6:34am
Subject: Re: Custom Roaster Wishlist
 

wcmocha Said:

Now you've got me wanting to rig up an IR sensor to play with when it's done.  That could be cool.  I've heard people say that with hot air you're roasting to a temperature more than a color.  True or not, It got me wondering if after a successfully documented roast you could duplicate it using a computer and temperature readings?

Posted April 12, 2013 link

With any roasting method you are roasting to a temperature more than color.  Various bean prep methods and origins produce different final color shades.  Also, color is effected by the type of ambient light (fluorescent v daylight v incandescent)  so it's a pretty inaccurate measurement.

Yes, if you are logging all your data and do the exact same profile on the same beans you will produce the same final roast profile.  

As far as the IR sensor - they are fun to play with but aren't all that accurate for roasting.  It is fun to see what approx temp the various parts or the roaster are operating at!    

Jon
back to top
 View Profile Link to this post
oldgearhead
Senior Member
oldgearhead
Joined: 25 Jan 2010
Posts: 395
Location: Go Colts!
Expertise: I like coffee

Grinder: Virtuoso by Baratza
Drip: Chemex,Dilongi DCM900
Roaster: 1/2K Fluid-bed
Posted Sat Apr 13, 2013, 7:17am
Subject: Re: Custom Roaster Wishlist
 

jkoll42 Said:

 

As far as the IR sensor - they are fun to play with but aren't all that accurate for roasting.  It is fun to see what approx temp the various parts or the roaster are operating at!    

Jon

Posted April 13, 2013 link

Oh, I wasn't talking about a Raytek. I mean a REAL one, like this:
http://www.omega.com/ppt/pptsc.asp?ref=OS35&Nav=temj11

But this one would be better for inside an RC, because you can maintain an air-wash through it:
Click Here (www.omega.com)

..
back to top
 View Profile Link to this post
wcmocha
Senior Member
wcmocha
Joined: 26 Dec 2010
Posts: 218
Location: Colorado
Expertise: I love coffee

Espresso: Gaggia Classic
Grinder: Nemox Lux
Drip: Keurig
Posted Sat Aug 10, 2013, 9:22pm
Subject: Re: Custom Roaster Wishlist
 

Been a while, but I've got the rough parts assembled and did a pressure test of the new sample roaster.  The bean compartment is all stainless and made from raw sheet.  High-temp glass is on the face.  I milled a block of aluminum to create a venturi that gradually direct the airflow where I want it.  There is a PID probe located in the most stagnant area of beans as well as a platinum RTD probe in the airstream below the venturi.  I have an electric heating element mounted in the airstream.  The next step is to build the controls for the element and then insulate a few places with high-temp ceramic material.  Oh, and I used a spa blower.  Here's a pic...

wcmocha: Roaster1sm.jpg
(Click for larger image)
back to top
 View Profile Link to this post
showing page 2 of 2 first page previous page
view previous topic | view next topic | view all topics
Discussions > Coffee > Home Roast > Custom Roaster...  
New Topics updated topics   New Posts new posts   Unanswered Posts new unanswered     Search Discussion Board search   Discussion Board FAQ faq   Signup sign up  
Not Logged in: Log In to Postlog in
Discussions Quick Jump:
Symbols: New Posts= New Posts since your last visit      No New Posts= No New Posts since last visit     Go to most recent post= Newest post
Forum Rules:
No profanity, illegal acts or personal attacks will be tolerated in these discussion boards.
No commercial posting of any nature will be tolerated; only private sales by private individuals, in the "Buy and Sell" forum.
No SEO style postings will be tolerated. SEO related posts will result in immediate ban from CoffeeGeek.
No cross posting allowed - do not post your topic to more than one forum, nor repost a topic to the same forum.
Who Can Read The Forum? Anyone can read posts in these discussion boards.
Who Can Post New Topics? Any registered CoffeeGeek member can post new topics.
Who Can Post Replies? Any registered CoffeeGeek member can post replies.
Can Photos be posted? Anyone can post photos in their new topics or replies.
Who can change or delete posts? Any CoffeeGeek member can edit their own posts. Only moderators can delete posts.
Probationary Period: If you are a new signup for CoffeeGeek, you cannot promote, endorse, criticise or otherwise post an unsolicited endorsement for any company, product or service in your first five postings.
Learn @seattlecoffeegear
Learn all about coffee, watch videos, read how-to articles.
www.seattlecoffeegear.com
Home | Opinions | Consumer Reviews | Guides & How Tos | CoffeeGeek Reviews | Resources | Forums | Contact Us
CoffeeGeek.com, CoffeeGeek, and Coffee Geek, along with all associated content & images are copyright ©2000-2014 by Mark Prince, all rights reserved, unless otherwise indicated. Content, code, and images may not be reused without permission. Usage of this website signifies agreement with our Terms and Conditions. (0.286061048508)
Privacy Policy | Copyright Info | Terms and Conditions | CoffeeGeek Advertisers | RSS | Find us on Google+