Our Valued Sponsor
OpinionsConsumer ReviewsGuides and How TosCoffeeGeek ReviewsResourcesForums
Espresso: Questions and Answers
Home made Scace device (kinda)
Support Coffee Kids
Coffee Kids is a non profit charity working with farming communities around the world. 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 > Espresso > Q and A > Home made Scace...  
view previous topic | view next topic | view all topics
showing page 1 of 2 last page next page
Author Messages
DeanOK
Senior Member
DeanOK
Joined: 24 Sep 2012
Posts: 715
Location: OK
Expertise: I like coffee

Espresso: QM Vetrano 2B
Grinder: Vario W
Posted Thu Sep 5, 2013, 6:37pm
Subject: Home made Scace device (kinda)
 

I ordered a 58mm blind basket and a K type thermocouple probe and I want to make my own 58MM device to measure temperature at the brew head using a bottomless PF. Total investemet is about 12 bucks because I already have a K thermocouple thermometer I can plug the K thermocouple probe into.

Now, putting a thermocouple in a blind basket is easy... the hard part is working on accuracy. For that I need a basket that wont draw heat away from the water so fast that I can't get an accurate water temperature and I need to control flow to about 1.75 ounces in 25 seconds or so.

I have decided that I will coat the inside of the basket with some coating or non thermal conducting material that will help maintain the water temperature in the basket. I hope to drill a very small hole in the bottom of the basket that will control flow within the required flow range ( we will see).

Here is how I will proceed to calibrate the device for an accurate measurement:

1) I will boil water and calibrate the K thermocouple by dropping it in the boiling water and then comparing the measured water temperature against the correct temperature for my elevation.

2) I will turn the heat off under the boiling water, and then immerse the entire PF with the basket attached into the water. I will then wait until the water temperature has dropped to within a few degrees of the set point of the brew temperature I am expecting from the espresso machine. By having only a few degrees difference in temperature between my brew water and my basket temperature, it will prevent the mass of the basket from drawing heat away from my brew water so I can get an accurate coffee bed water temperature (that's my plan anyway).

3) Just before removing the PF from the hot water, I will do a cooling flush if needed and then I will pop the PF out of the hot water and into the machine.  I will start the pump and record the temperature for the next 30 seconds.

Will this be an accurate method? I think this will be within 1 degree F. I know in the real world the PF basket is not necessarily the same temperature as the brew water, but I feel like the coffee puck adds insulation that will prevent rapid cooling of the water... at least on top of the puck. Any thoughts?
back to top
 View Profile Link to this post
calblacksmith
Moderator
calblacksmith
Joined: 25 Nov 2007
Posts: 7,947
Location: Riverside, Ca, U.S.A.
Expertise: I live coffee

Espresso: ECM Vene. A1, La Cimbali M32
Grinder: Azkoyen Capriccio, Major
Vac Pot: 40s era Silex
Drip: Msl. Com. brewers
Roaster: gave it a try, decided no
Posted Fri Sep 6, 2013, 7:42am
Subject: Re: Home made Scace device (kinda)
 

The first Scace device was home made by a person named Scace so you are on the well trodden track!

The whole point of the device is to simulate as close as possible the conditions when pulling a shot. This requires a water flow through the device to simulate the water flow through the puck of coffee. I think the way most solve this issue is to use a needle valve to adjust the flow of water.

When calibrating your temp probe with boiling water, do not forget to include your altitude in the calculations. The higher up you are from sea level the lower the temp water boils at, this is why cooking when camping in the mountains takes longer than most peoples homes. UH, just saw you compensated for that, good.

My personal view is that getting the water flow correct via time will be better than trying to insulate the water for temp. The pressure on the machine is set while the water is flowing not at a static pressure.

 
In real life, my name is
Wayne P.
Anything I post is personal opinion and is only worth as much as anyone else's personal opinion. YMMV!

Feed the newbs, starve the trolls and above all enjoy what you drink!
back to top
 View Profile Visit website Link to this post
D4F
Senior Member


Joined: 15 Mar 2012
Posts: 2,025
Location: USA
Expertise: I like coffee

Espresso: Gaggia Classic PID
Grinder: Baratza Forte-AP
Posted Fri Sep 6, 2013, 8:35am
Subject: Re: Home made Scace device (kinda)
 

You will need correct flow rate and reasonably close temperature.  I leave the PF and basket in the machine, same as I do when heating up the machine to brew.  Hole size is interesting, I doubt that you will be able to drill that hole as it is quite small.  I did not have that capability, but perhaps you have better tools/shop.  You can drill and put in a valve or use a small wire and epoxy and pull the wire.

Wire and hole size here.

Click Here (coffeegeek.com)

 
D4F also at
http://www.gaggiausersgroup.com/
back to top
 View Profile Link to this post
DeanOK
Senior Member
DeanOK
Joined: 24 Sep 2012
Posts: 715
Location: OK
Expertise: I like coffee

Espresso: QM Vetrano 2B
Grinder: Vario W
Posted Fri Sep 6, 2013, 10:09am
Subject: Re: Home made Scace device (kinda)
 

D4F Said:

Hole size is interesting, I doubt that you will be able to drill that hole as it is quite small.  I did not have that capability, but perhaps you have better tools/shop.  You can drill and put in a valve or use a small wire and epoxy and pull the wire.

Wire and hole size here.

Click Here (coffeegeek.com)

Posted September 6, 2013 link

I may not... the bits I have are so small I will have to use a hand drill most likely. My plan was to start with the smallest one I had and see how it goes and the increase size if necessary. If it doesn't work, I was planning on putting a valve in. I was hoping to keep in simple.
back to top
 View Profile Link to this post
DeanOK
Senior Member
DeanOK
Joined: 24 Sep 2012
Posts: 715
Location: OK
Expertise: I like coffee

Espresso: QM Vetrano 2B
Grinder: Vario W
Posted Sat Sep 7, 2013, 6:25pm
Subject: Re: Home made Scace device (kinda)
 

Well, here is what I came up with. Tomorrow will be first test run after the silicone that I glued the foam in with sets. I went ahead and used a needs valve so I could make sure I could adjust it. I couldn't find a needle valve that didn't have at least one connection set up as a compression fitting, so I put a compression cap on the outlet and drilled about an 1/8" hole in it so that it would direct the water downward. The foam is sealed against the blind and the thermocouple probe is sticking right in the middle. The probe is glue in through a hole that is sealed with epoxy. I didn't think to check that foam to see if it would melt at 200F, so I hope I don't have a melted mess tomorrow. Its a different kind of foam than foam used in drinking cups, so maybe not.

DeanOK: scace_device_small.jpg
(Click for larger image)
back to top
 View Profile Link to this post
D4F
Senior Member


Joined: 15 Mar 2012
Posts: 2,025
Location: USA
Expertise: I like coffee

Espresso: Gaggia Classic PID
Grinder: Baratza Forte-AP
Posted Sat Sep 7, 2013, 7:00pm
Subject: Re: Home made Scace device (kinda)
 

Looks good.  What epoxy did you use?  Some will soften at high temperature and will allow a blow out at 9 bar.  You may be able to look up the specific product temperature.  the foam may well be fine. Foam cups can hold hot beverage and do the "Styrofoam Cup Test."  You could stick the basket in boiling water for a couple minutes before you test it with heat and pressure :)

A little more on construction/pictures would be nice if it works.

 
D4F also at
http://www.gaggiausersgroup.com/
back to top
 View Profile Link to this post
DeanOK
Senior Member
DeanOK
Joined: 24 Sep 2012
Posts: 715
Location: OK
Expertise: I like coffee

Espresso: QM Vetrano 2B
Grinder: Vario W
Posted Sat Sep 7, 2013, 7:30pm
Subject: Re: Home made Scace device (kinda)
 

D4F Said:

Looks good.  What epoxy did you use?  Some will soften at high temperature and will allow a blow out at 9 bar.  You may be able to look up the specific product temperature.  the foam may well be fine. Foam cups can hold hot beverage and do the "Styrofoam Cup Test."  You could stick the basket in boiling water for a couple minutes before you test it with heat and pressure :)

A little more on construction/pictures would be nice if it works.

Posted September 7, 2013 link

I used JB weld (mostly because I already had some). The foam I used was not the same as the foam in a cup... its more of a packing material. The only reason I used it was to keep the metal in the basket from drawing heat away from the water temperature probe. In the real world, there is coffee packed in there to act as an insulator, so I was trying to mimic the layer of coffee thermally.
back to top
 View Profile Link to this post
D4F
Senior Member


Joined: 15 Mar 2012
Posts: 2,025
Location: USA
Expertise: I like coffee

Espresso: Gaggia Classic PID
Grinder: Baratza Forte-AP
Posted Sat Sep 7, 2013, 7:50pm
Subject: Re: Home made Scace device (kinda)
 

JB weld is great for this as it is for high temperature.  I realize that the foam is a puck simulator, and it will probably be heat stable at 200F. I will look for your results.

 
D4F also at
http://www.gaggiausersgroup.com/
back to top
 View Profile Link to this post
DeanOK
Senior Member
DeanOK
Joined: 24 Sep 2012
Posts: 715
Location: OK
Expertise: I like coffee

Espresso: QM Vetrano 2B
Grinder: Vario W
Posted Sun Sep 8, 2013, 2:21am
Subject: Re: Home made Scace device (kinda)
 

Well, I tried it this morning... have a problem I never anticipated. Water is actually running down the INSIDE of the thermocouple wire and coming out at the plug. I will try to seal the end of the wire with epoxy. if that doesn't work, I will have to find a different thermocouple wire.
back to top
 View Profile Link to this post
D4F
Senior Member


Joined: 15 Mar 2012
Posts: 2,025
Location: USA
Expertise: I like coffee

Espresso: Gaggia Classic PID
Grinder: Baratza Forte-AP
Posted Sun Sep 8, 2013, 11:46am
Subject: Re: Home made Scace device (kinda)
 

I should have mentioned that.  I could not tell from your picture which insulation.  Fiberglass insulation does not seal to the wire.  It might in this Teflon thermocouple.

http://www.ebay.com/itm/310565791082

I did not test for water seal, but this Teflon coating seemed to be adhered to the wire.  I corresponded with AndyPanda who used to post here.  He mentioned the same problem that you noted and got enough bare wire to glue the wire beyond the insulation as you are suggesting.  Gluing the bare wire worked.  You can always test for calibration with boiling water and freezing.  JB is metallic based and in theory could change the values some.  I used the copper tube to insert the thermocouple so that it is sealed and changeable if the wire breaks, but it adds some damping.  Scaces/thermocouples are not simple.

 
D4F also at
http://www.gaggiausersgroup.com/
back to top
 View Profile Link to this post
showing page 1 of 2 last page next page
view previous topic | view next topic | view all topics
Discussions > Espresso > Q and A > Home made Scace...  
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.
Rancilio Silvia - How to
Step by step guide for easy brewing and steaming with the Rancilio Silvia
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. (0.313242912292)
Privacy Policy | Copyright Info | Terms and Conditions | CoffeeGeek Advertisers | RSS | Find us on Google+