Post mods and tips for Sunbeam Cornelius popper as resource for all owners

[jesuislepop]

Hi All,


Have just invested in a Sunbeam Cornelius popper to embark on roasting my own coffee.
Have searched the site high and low (as best i could) and found a scattering of posts amongst various threads that contained useful and relevant info regarding using the Cornelius.

Being one of the most common poppers on the market and therefore probably one of the most commonly used for roasting coffee, I thought it would be a good resource for any owners of this machine to start a thread that is purely for detailed information and tips regarding the use and modification of this particular popper.

For more general info, Ive read (and recommend to anyone else) the beginners guide to Roasting using a popper compiled by lucinda here:
http://coffeesnobs.com.au/YaBB.pl?num=1174699442


In particular, the initial questions that I have and cant find definitive answers for are:

1. How exactly can one open the machine safely to then begin modifying anything inside?

2. How to go about modding the auto kill-switch that engages with the lid open? In another thread, someone has said "remove the white plastic rod  inside the machine", can anyone provide photos or exact details on how to safely remove this white plastic rod?

3. How to remove thermal overload? This was alluded to by user KANDA in this thread:
http://coffeesnobs.com.au/YaBB.pl?num=1308189551
Im going to PM KANDA to ask for details on this, will post them if/when I get them.


Now for the mods that seem simple enough and have been explained precisely:

1. The Chimney. Seems to be crucial. Well explained here:
http://coffeesnobs.com.au/YaBB.pl?num=1174699442

2. Expanding the air vents (to assist cooling - located on the bottom of the Cornelius). Seems to be optional. Quoting KANDA here:
"...expanded the air vents in the popper with a screwdriver. i did this by inserting the blade and twisting it this made a peak in the fin."



One last but important thing, quoting Mal here:
Just remember guys and gals, once you start modifying any aspect of an Approved Electrical Device, you downgrade its integrity and therefore the legality of its use.
240V AC can and does KILL
so be very wary of dealing with something for which you are not qualified or licensed...

[jesuislepop]

Re: Post mods and tips for Sunbeam Cornelius popper as resource for all owners

OPENING THE UNIT

Well, I went ahead and found how to open it, so Ill at least add that here for now. The screws to get inside are located under the rubber feet on the bottom of the unit. Just pull firmly on the rubber feet and they come out, exposing the screws - youll need a long and narrow screwdriver to get in there.
Also one of the four screws on mine had a triangle shaped groove (like an allen key groove but in a triangle), i used a large flat headed watchmakers screwdriver jammed into one side of triangle and with a little trouble got it out.


RANDOMLY DISENGAGED AUTOSWITCH ON LID

I then found that if I loosened off the three screws holding the circuitboard/wiring onto the rest of the unit a little, this made the autoswitch less sensitive. I can have the lid fully open now when roasting (allowing room for chimney), the autoswitch doesnt engage until I bend the lid back slightly against its hinge.

[taco]

Re: Post mods and tips for Sunbeam Cornelius popper as resource for all owners

2. How to go about modding the auto kill-switch that engages with the lid open? In another thread, someone has said "remove the white plastic rod inside the machine", can anyone provide photos or exact details on how to safely remove this white plastic rod?


On mine I had a white wire run from the power switch to the kill switch, then from the other side of the kill switch to the rest of the popper.
So I removed the auto kill switch completely and connected the wire from the far end of the kill switch directly to the power switch.
No soldering required.


I couldnt find anything that would get the single security screw out, so I melted it out, and just use the remaining three screws to hold the unit together.

[jesuislepop]

Re: Post mods and tips for Sunbeam Cornelius popper as resource for all owners

Ok, just an update to leave here for anyone needing info now or in the future - I managed to pull off a simple but very effective modification for the cornelius.

The mod was to expand the air vents (in the roast chamber). To do this I needed to take off the entire casing, then with a flathead screwdriver I could just get enough angle to wedge them open 50-80% further (in the centre of the vent).

My roast times have gone from 4-5 minutes (and having to stop because its burning!), to 7-9 minutes.

Removal of outer casing requires first taking off the bottom (via screws under rubber feet), then undoing the three screws on the inner casing (youll see what i mean), then gently undo the two clasps connecting to the main power switch, then carefully take out the power switch (note the plastic jags, you can only reach one, get this out then just wiggle / lever it out). After all that, the casing will come off.

While youre in there, theres a massive white rod of plastic (goes higher than the chamber), this is the trigger for the autoswitch, break that badboy off somewhere far below where it currently is (use wire cutters) and the autoswitch is history.

[skelly]

Re: Post mods and tips for Sunbeam Cornelius popper as resource for all owners

I just bought a Cornelius ($45) and a pack of reenact beans that are selected for air roasting...not sure the exact type. My initial results are:

125ml beans and turn it on.
Stir for 1min using a metal skewer Poked through a hole in the lid.
First crack begins at 2 mins and lasts for 2 mins.
Second crack begins at 6 mins.
I Stopped at 9 mins , there was still some crackling at that point.

Beans appear a shade darker both inside and out than my professionally-roasted "full city" beans.
About 5-10% of my beans appear to have round scorch marks (burned oil?)
They smell a little burned, even after two days.

I took your suggestions on opening the air vents.
You dont need to dissassemble the machine at all.

Take a pair of pliers and a typical countersunk-head screw.(eg 2x25mm self tapper).
Hold the thread in the pliers, at a right angle.
Lower screw into the popper and use the head of the screw to gently prise out the air vents..theyre very thin aluminium so its quite easy.
Takes 2 mins.

I opened the vents by about 0.5mm, but wasnt trying to be too exact.

My first attempt with the modified machine an hour later:
Again 125ml.
I heard a few distinct first cracks at 5 mins, but not in great number.
The cracks continued but very slowly and i turned the machine off at 15mins as the plastic seemed to be getting very hot and not much was happening.
The colour of the beans is what I would call a light to medium roast.

Ill taste both batches and report back. Might try closing the vents slightly in future.
It does appear that changing the vents changes the temp. Ill have to invest in a thermometer.

Overall impressions of home roasting: easy, cheap, quick, interesting, kind of exciting even... so why not give it a whirl?  8-)

[skelly]

Re: Post mods and tips for Sunbeam Cornelius popper as resource for all owners

^Okay, followup to the above:

First roast (2min, 6min, end at 9) smelled burned, but tasted quite good.

Second roast (3min, 6min, end at 10) also smelled burned, tasted similar

Third roast - Opened vents - (5min, no 2nd crack, end at 10) - lighter colour, tasted a bit flavourless

Fourth roast - placed the lid over the vents - similar results to above - 1st crack incomplete, unable to reach 2nd crack

Fifth roast - closed vents a bit - 1st crack 4 mins, no second crack - Better flavour, some burned aroma, still tasting a bit flavourless.

Sixth roast - closed vents a bit more and placed lid over - 1st crack 4 mins, no second crack, stopped at 10 after burned aroma became stronger. Havent tasted yet.

Crema, pour time, colour of the coffee - all excellent, usually (sometimes pour time & volume is faster than I expect). Grinds are lookign light & fluffy. Im leaving the beans for about 2-3 days after roasting.

Its difficult for to tell what the beans should taste like, as they arent available pre-roasted. Surprisingly they dont taste bad regardless of how careless I am with the roast, or how much the time varies.. Im closing the vents up progessivly because I think my earlier attempts (which got to 2nd crack) might be the way to go...at least there was more flavour.

Im concerned about the burning aroma, and the heat of the machine (the clear plastic lid of the machine is beginning to exhibit hairline cracks).


Back to the drawing board for tomorrow......

[kike10]

Hi all, I also started roasting with the cornelius. First roast was way too quick 2nd crack in about 3 mins, the beans smelled burnt, I let them sit for a few days then tried them and it wasn't too bad.
My second attempt I opened all the vents and I did not get any cracks had it on for over 20 mins, the beans smelled really smoky I just binned them.
So for my third attempt, I closed most of the vents back to original or so, put a fan in front of popper to get to first crack which started at about 3 mins, then turned the fan off to get 2nd crack, which started at 4 mins. I stopped it just before 2nd crack as the smell changed. I think that's the key not to just wait for second crack, notice the change of smell just before the second crack.

Cheers