Air Popcorn Popper Roast Profiles - Page 4

Discuss roast levels and profiles for espresso, equipment for roasting coffee.
mpdeem (original poster)
Team HB

#31: Post by mpdeem (original poster) »

Smplif8 wrote:I built one a few years ago using a West Bend popper with DIY arduino based PID control, I borrowed and modified someone's PID code for a kiln control that has the ability to set the independent temperature increase rate in segment, soak time can also be set per segment. The fan speed can be controlled manually. Graph with artisan is also possible, though a little tricky.

With an added chimney, maximum capacity my roaster is around 190 gram per batch, but I usually do 150 gram batch.

The thing is, I can't taste any note from any coffee, but I know my coffee is smooth. I mainly make latte using an old Expobar Brewtus machine, with a Sette 270 grinder.
Thanks so much for the photos and detailed description of your Poppery I set up. I love the wooden case for your PID. You mention using an altered code from a PID used for a kilm...I am assuming one used to fire clay or other ceramics? My husband is a retired software engineer (Apple) who does both high and low level programming...so of course he was quite interested in your description. I have a PID from Auber which is programmed for sous vide cooking. Had debated finding one programmed for roasting..but a lot of PIDs are geared towards commerical home roasters as opposed to 'frankenroasters' like ours.

I am also interested in your manuel fan speed control. Right now my WB Poppery I has the heat and fan switches seperated so I can turn off the heat while keeping the fan running. Neither the fan or heat rate/speed is adjustabe beyond basic on and off positions. I would love to have fine tuning/modulation of each-but particularily fan speed since my particular Poppery has a somewhat more powerful fan than previous Poppery I models that I have owned.

Are you using the stock motor that came with the Poppery I? I have considered replacing the motor and heating element just to have something a little stronger..but not absolutely necessary at this point.

You mention not being able to taste any flavor (I assume) note from your roasts...rather just able to tell that it is smooth. I admit this surprises me given your set up and ability to control the roast. Do you roast on another platform aside from your popper? If so what type? Again just surprised as you have quite a nice set up there.

Type and location of temperature probes would be helpful...maybe you have indicated it somewhere and I missed it? I am just using a basic cooking thermometer mounted from the side into the roast chamber but am able to get quite flavorful roasts.

Could you share some of your profiles or general 'roast recpes' that you use? Be sure to include type of coffee and source too. With any luck someone here may have expierence roasting the same coffee and can offer some input. In the first year of roasting I quickly discovered the importance of using really good greens...as there are a lot of very bland medicore coffees out there.

Also there is of course individual palate senstivities and perception that come into play. For example I sometimes struggle to find all the subtle nuances of some nutty type Brazil and El Salvador coffees...to me sometimes they seem one dimensional.

Some coffee retailers offer both green and roasted versions of the same coffee which can be very helpful in having a sort of benchmark against which to compare one's roast -even if the roast platform is different...still gives one a general idea of what the basic flavor profile tastes like. Another option -and a fun one at that -is to swap greens and roasts of the same coffee...which is someonething we might all consider some time. Would be fun to see what everyone is getting from their popper. This being of course in the spirit of fun and learning...and decidedly not competition...one man's idea of taste being one one's notion of bland or 'yuck' ;)

Thanks again...beautiful set up...giving me more inspiration for future upgrades.

Smplif8

#32: Post by Smplif8 »

mpdeem wrote:Thanks so much for the photos and detailed description of your Poppery I set up. I love the wooden case for your PID. You mention using an altered code from a PID used for a kilm...I am assuming one used to fire clay or other ceramics? My husband is a retired software engineer (Apple) who does both high and low level programming...so of course he was quite interested in your description. I have a PID from Auber which is programmed for sous vide cooking. Had debated finding one programmed for roasting..but a lot of PIDs are geared towards commerical home roasters as opposed to 'frankenroasters' like ours.

I am also interested in your manuel fan speed control. Right now my WB Poppery I has the heat and fan switches seperated so I can turn off the heat while keeping the fan running. Neither the fan or heat rate/speed is adjustabe beyond basic on and off positions. I would love to have fine tuning/modulation of each-but particularily fan speed since my particular Poppery has a somewhat more powerful fan than previous Poppery I models that I have owned.

Are you using the stock motor that came with the Poppery I? I have considered replacing the motor and heating element just to have something a little stronger..but not absolutely necessary at this point.

You mention not being able to taste any flavor (I assume) note from your roasts...rather just able to tell that it is smooth. I admit this surprises me given your set up and ability to control the roast. Do you roast on another platform aside from your popper? If so what type? Again just surprised as you have quite a nice set up there.

Type and location of temperature probes would be helpful...maybe you have indicated it somewhere and I missed it? I am just using a basic cooking thermometer mounted from the side into the roast chamber but am able to get quite flavorful roasts.

Could you share some of your profiles or general 'roast recpes' that you use? Be sure to include type of coffee and source too. With any luck someone here may have expierence roasting the same coffee and can offer some input. In the first year of roasting I quickly discovered the importance of using really good greens...as there are a lot of very bland medicore coffees out there.

Also there is of course individual palate senstivities and perception that come into play. For example I sometimes struggle to find all the subtle nuances of some nutty type Brazil and El Salvador coffees...to me sometimes they seem one dimensional.

Some coffee retailers offer both green and roasted versions of the same coffee which can be very helpful in having a sort of benchmark against which to compare one's roast -even if the roast platform is different...still gives one a general idea of what the basic flavor profile tastes like. Another option -and a fun one at that -is to swap greens and roasts of the same coffee...which is someonething we might all consider some time. Would be fun to see what everyone is getting from their popper. This being of course in the spirit of fun and learning...and decidedly not competition...one man's idea of taste being one one's notion of bland or 'yuck' ;)

Thanks again...beautiful set up...giving me more inspiration for future upgrades.
Here is the link to the kiln controller I borrowed: https://create.arduino.cc/projecthub/Mr ... ler-f5c633

My popper has the transformer mod to increase the fan supply voltage by about 24v, from 110v to about 134v, it will not be able to handle 190 gram of load otherwise. The fan's supply is separated from the heating element's which is obviously controlled by PID, fan speed is controlled by regular dimmer or ceiling fan rotary speed controller from home center.

About coffee tasting, I did sign up for a trial from one of those subscription based roaster, I didn't taste any note either and didn't think their roast was better than mine. I read people mentioned here that you will need to get "trained" in order to taste all these fancy notes, I don't have time and place to get such training, I choose to enjoy a cup of latte every morning and forget about the notes, for now :)

Here is a couple more pictures of my popper, one shows the chamber and the thermocouple in it.


buckersss
Supporter ♡

#33: Post by buckersss »

mpdeem wrote:Thank you so much for posting your roaster schematic and sample profiles. The red variac looks suspcously like the one I purchased (from Amazon) therefore I have to ask have you had issues blowing circuits while using it while roasting? I never used mine so my husband used it for a project -can't remembr what- but he blew two circuits before deciding to put it on a separate breaker.
Not owning one, but having looked at the listings, there seem to be many skus that look virtually identical. You have to know the power rating on yours. Less than 2000kva, it's possible you'll trip a breaker. It depends on your roaster.
Smplif8 wrote:
Here is a couple more pictures of my popper, one shows the chamber and the thermocouple in it.
image
image
Awesome pics! Is that a custom case for the PID? It looks fantastic. Any chance the cover easily comes off and you can show us under the hood?

randytsuch

#34: Post by randytsuch »

mpdeem wrote:I think you are correct....seem to recall folks on both Sweet Maria's old forum & the Home Roast forum (when it was still very active) were using Pumpers in place of the Poppery for the same reasons you mention here. I might keep that in mind next time I need to replace my Poppery I....as the prices have gone way up on ebay.

The thermostat is disabled and the heat & fan switch seperated on my Poppery. Interesting that the same modifcations can be made on the Pumper. I wonder if it is literally the same internal schematic being used for both brands.
The internal wiring is pretty simple from what I recall, so likely is either identical or very close.

Some other details.
For my chimney, I used two soup cans. They fit perfectly in either a Poppery I or the original Pumper. I have two of them stacked, and bought some insulation from Mcmaster. Insulation helps to hold them together, retain heat, and make chimney safer to handle.

I'll try to remember to post some more pics of my Pumper, its still in the garage somewhere.
For reading Bean Temp (BT), I drilled a hole in the side, near the top of the chamber, just below where the chimney slides in. I stick a type k thermocouple probe in the hole so its centered in the middle of the pumper.
When roasting, this did a good job of measuring temp of bean mass.

PID was controlled by the thermocouple I had that measured the temp of the hot air as it entered the chamber, I called this Environmental Temp (ET)

Randy

minus1psi

#35: Post by minus1psi »

buckersss wrote:If you run the popper attached to a variac you should be able to do some tuning and achieve different heat levels.

IE drop voltage to ~110 and slowly rise up to ~120. Watch for temperature change (without beans) before moving to next dial notch. Move dial up a notch and then drop voltage down again and repeat. When temps are charted you should be able to identify the redundant, or missing, points and adjust the voltage window as required.
Great idea. Here is something along those lines inspired by that thought. I ran a test from 105v to 125v with an empty chamber. I 'charged' the roast at 203°F and 105v. Every thirty seconds the voltage was increased 1v. The roast was 'dropped' 30 seconds after reaching 125v. (For no compelling reason 'Dry End' was marked when voltage reached 115v.)

255.7°F was he maximum temperature reached in this test; it was reached after more than 10 minutes of continuous power and regularly increasing voltage. For the sake of comparison, with beans in the chamber, BT reaches temperatures in excess of 255°F in a matter of only a few seconds even at lower voltages.

My initial thought is that the chamber does not pop popcorn or roast coffee by becoming hot. This machine is, as marketed, a hot air popcorn popper. Although I was a bit surprised by the curve below I should not have been. The heat produced is convective. As the beans heat up I am pretty sure a conductive quality is also in play, but the conduction is bean-to-bean (B2B :D) much more-so than chamber-to-bean.



Edited to delete some information added after the original post because the added comments seemed to increase confusion without adding additional value

[snip][/snip]

Squeezin' Beans

#36: Post by Squeezin' Beans »

I get the same results with my modified WBP2 with Variac. Similar temperature range and near instant temp change with voltage. The factors controlling thermal response rate appear to be the overall mass of beans and the airflow resultant since I'm only controlling it with bean mass and haven't added a control for fan speed yet. I will do that next as it seems to be a key factor.

minus1psi

#37: Post by minus1psi »

@Squeezin' Beans Thanks! That's cool.

randytsuch

#38: Post by randytsuch »

I used a Fan dimmer made by Lutron to control fan speed.

It worked fine, could control speed if I wanted to. But that was a manual process, I think I got better, more repeatable results by leaving fan at full speed, and using PID/SSR circuit to control the heater.

Although you could use the dimmer to slow down the fan, and leave it at a constant, slower speed for all roasts.

mpdeem (original poster)
Team HB

#39: Post by mpdeem (original poster) »

minus1psi wrote:My initial thought is that the chamber does not pop popcorn or roast coffee by becoming hot. This machine is, as marketed, a hot air popcorn popper. Although I was a bit surprised by the curve below I should not have been. The heat produced is convective. As the beans heat up I am pretty sure a conductive quality is also in play, but the conduction is bean-to-bean (B2B :D) much more-so than chamber-to-bean.
I think you are on to something here...in particular the reference to the conduction being bean-to-bean.

I have been experimenting with trying to do lighter roasts since over the last few years it seems I have had to go darker in my roasts to retain sweetness and flavor complexity. I was wracking my brain trying to figure out what had changed because now I seem incapable of roasting lighter without loss of sweetness or else developing slightly vegetal flavors. The first 5-6 years of roasting I mostly did very lighter roasts...city-city + level roasts that were lovely. How ironic it was now that my roasts are closer to FC yet I seem unable to go back to lighter style roasts.

Going over some old roasting notes from 3-5 years ago, I noticed that I used to roast larger volumes of beans. Over the last 2-3 years I had slowly been reducing the volume of beans per roast, in an effort to avoid bean tipping and increase chamber air circulation. I suspect that with a reduction in bean volume -even of a mere 1-2oz (physical cup measurement not weight here), there was a loss of thermal mass heat-heat conductivity. This would explain why I have had to raise my maillard temp range and peak temperature.

Reading your post it suddenly dawned on me that perhaps the solution was as simple as increasing the volume of beans. I did a few roasts, using my old 'stuff the chamber' asmount of .8-8oz cup of raw beans. The results were excellent. I was able to lower my peak temperature by 5-10 degrees without sacrafice of flavors or sweetness yet achieve a city + level roast.

An interesting note regarding temperature. With a larger raw bean volume that is almost full capaicity of my roaster, I noticed that despite my temperature dial indicating the usual temperature range approaching 1st Crack on thru mailliard and end, the beans behaved in a manner suggesting a higher internal temp. For example at 5:30 I heard a snap and backed off the heat even though the temp dial indicated 350 F - and I normally don't reach 1st Crack unitl 7-7:20 minutes..and don't get any early snaps until 6:30 normally. By the time I was approaching 1st C at 6:45 I was going off the bean color more than the dial since the latter appeared to be quite far off from actaul bean temperature. This was confirmed in that through 1st Crack and maillard I had to back off the heat more than usual (for the last 2-3 years).

So I think you are spot on here..that it might be better to approach poppers like a convection oven using bean volume and thermal mass as better indicators than environmental measured temperature. Having said that, my expierence withconvenction ovens is about nil...so I would love to hear more about means of measuring and profiling thermal mass 'bean-to-bean conductivity (as opposed to using environmental temperature).

Thank you to everyone who is contributing to this thread. This comes at a time when I have been tinkering with my roasts profiles for the first time in years...and hitting a wall because I have been going off the concept of environmental heat as primary force in my roasts.

mpdeem (original poster)
Team HB

#40: Post by mpdeem (original poster) »

randytsuch wrote:I used a Fan dimmer made by Lutron to control fan speed.

It worked fine, could control speed if I wanted to. But that was a manual process, I think I got better, more repeatable results by leaving fan at full speed, and using PID/SSR circuit to control the heater.
Thanks for the info. Will probably focus first on heat for the reasons you mentioned otherwise might get too many variables in the mix. I just discovered that reducing bean volume over the last few years as resulted in radical changes in my roasts..forcing me to roast hotter and darker due to changes in thermal heat (less beans = lower bean temps). So in light of that, I will probably not seek to increase dan speed-circulation for now.