Having an Issue? Popper Troubleshooting Tips

Roast too fast? Not dark enough? Something seems wrong with the roaster? Here’s some tips to solve Popper coffee roaster problems

This is an FAQ format page to address various questions and complaints we have had about the roaster, including issues with defective machines!

So far Popper has proven to be reliable, and we have some customers with 100+ roasts completed.

When you manufacture an appliance en masse you are told to expect a defect rate between 1.5% and 3%. That’s not due to a specific problem, but simply that somewhere in the parts and assembly, things aren’t perfect.

But Popper rate of defect has been well under 1% at this point, so we are doing pretty good! This is not surprising, because we have these made at a very reputable factory that designs and builds appliances for major brands. They even have our UL certification/testing staff embedded within the plant. On top of that, we hire a 3rd party testing service to randomly pull out units and test them. Some of you might have noted a small label “ITS” on the box of your popper. ITS = Independent Testing Service.

popper is a coffee roaster
popper is a coffee roaster

The majority of emails citing issues have been some confusion with directions, especially for people who have roasted before. (You read that right). It seems first-time users will tend to read directions more than experienced roasters! So here are some of the issues we have heard about, and how to address them! These are taken from emails we received…

There are three sections below: Troubleshooting Roasting Problems, Roaster Defect Problems, and Modification of Popper.


Troubleshooting Roasting Problems

The instructions say to roast 100 grams. My machine roasts fine, but only seems to roast 80 grams or so.

Short Answer: Try a different outlet.
Our new instructions will read 90 gram capacity, just to make sure we are under-promising a little. The fact is all units we test roast 100 grams of standard size and weight washed coffee. (You have to make adjustments for some other processes and varieties of green coffee though! They don’t all spin the same.)
That said, we have looked at 2 roasters returned for this issue, and both were fine. They roasted 95-100 grams. Without being able to verify this totally, I have to say I think it’s voltage issues with those 2 owners. Some people have older homes that don’t truly rate 120v at the outlet. Others have another load on the same line drawing power, or more obvious issues, like roasting with an extension cord .(Don’t!).
If you cannot test your line voltage (and the voltage drop that occurs when you use the roaster) then try to find an outlet closest to your electric fuse panel and test the machine there. Or try the machine at a friends house, especially if yours is older construction or has modified or converted electric service. Popper is 1200 watts and needs a good electric supply to work at it’s best.
Another issue here might be in the interpretation of what a good initial rotation of the coffee should look like. If the coffee is moving slowly for the first 30 seconds and gains speed, that is normal! You definitely want to weigh EVERY batch and be consistent, and use a batch size that does result in increased motion of the coffee over the first 30 seconds, If your coffee isn’t spinning at all after 30 seconds, you should stop the roast and remove some! But slower initial rotation is totally fine. Check out our video on this!
In any case, we haven’t seen a roaster that is said to roast only 80% of its capacity that is an actual machine defect – so far they have all been something with the environment they are used in.

I was roasting inside but now have to roast out in the garage, and it’s cold out! I am not getting the same roasts and it seems the machine isn’t working as well any more.

Short Answer: Outside roasting is an issue…. read on…
This might be a compound problem, and one we have seen with other coffee roasters too, especially air roasters. The first issue is ambient temperature. Higher velocity roasters like Popper will definitely roast differently when surrounded by colder air.
The second issue is often the quality of the electric supply in a garage or patio etc. Popper, and other roasters, need a good quality 120v outlet, and garage plugs or outdoor plugs are sometimes not the best.
There’s a safety concern too : Our experience is that people sometimes “take a break” from watching their roaster when they somewhere cold. We had a guy doing winter-time roasting on a patio table, but would sit inside where it was warm. Even though he was “10 feet away” he really couldn’t hear, see or smell the roast, and the coffee charred to a crisp and partially melted the machine. DON’T be that guy!
If you roast in a colder environment, you need to be doubly careful to watch the machine. They roast is absolutely going to be different. And the thermal sensor on the machine likely won’t regulate the high temperature in the same way when it’s cold out. I am sure there’s a safe way to manage all this, but please be aware of the risks in roasting in a garage or other colder place, and stay with your roaster at all times!

I am hitting first crack at around 3 minutes. Is this normal?

Short Answer: Change initial heat setting.
It’s possible to roast really fast in Popper, but not ideal. I like to see first crack start at 4 minutes at the soonest (which would read 6:00 on the count-down timer). I feel my best roasts have come from 1st crack at around 5:30 into the roast (which = 4:30 on the countdown timer). I would suggest roasting at a setting of about 1:15 on the heat dial, read as an analog clock face, and turning it down to 1:00 or just under, if that seems a bit fast. Using small adjustments around the 1:00 heat dial position has worked best for me. Fan is ALWAYS set to High initially, and if you want you can turn to Low as first crack approaches as a way to raise the heat in the roast chamber. Here’s our video on roaster adjustments.

My roasts are taking too long. It seems to stall when the coffee turns light brown, but hasn’t hit first crack yet.

Short Answer: Change heat settings.
It’s good to use a gentle warm-up, then slightly increase temperature to bring on 1st crack. You can also switch from High air flow (always start your roasts in High fan speed, 100% of the time!) and switch to low nearing first crack. Once the coffee is brown, it has lost enough weight in the form of moisture content, to make using Low fan speed practical. A combination of slight rise in the Heat setting knob, plus switching to Low fan speed will usually bring on first crack. If your roasts take over 9-10 minutes to hit first crack, I would consider that too slow in an air roaster like Popper. That could be fine in a drum type roaster, but in an air roaster it might lead to a “baked” taste in the coffee. I would target a slower roast in Popper, such as one for espresso, at around a 7:00 first crack, finishing up the roast around 10:00 total roast time (extended from the default using the timer). I have enjoyed some roasts that were as long as 12;00 total roast time, but not all. Some definitely seemed a bit baked.

I can’t get my roasts dark enough in Popper.

Short Answer: Popper isn’t good for Italian roasts, but …
There’s well-developed roasting, and then there’s burnt coffee. If you mean burnt, then Popper isn’t the best for dark roasting. We say that right up front in our descriptions, because home roasting appliances need to be safe, and really dark roasts reach the point of igniting the coffee: fire. The way to roast super dark are non-appliances like stovetop skillet roasting or a stovetop popper. You are going to deal with a lot of smoke and residue from dark roasting though. Popper can definitely produce intense pungent roast flavors, but not charred and burnt oily coffee beans. As I said, there isn’t a home roaster that really will, because it’s just not safe, plus, it really defeats the point. Roasted to that level, coffee basically tastes the same, regardless of where it is from, or how good the green coffee is. It’s best to buy some coffee on Ebay or Amazon, and roast in an iron skillet or modified barbeque drum outdoors, if that’s what you like!
That said, we do have a video with tips for getting coffee into second crack, and we have modified test versions of Popper to do so with ease. We don’t recommend modification as it voids the warranty though. Here’s our video on roasting darker and other adjustments.

Around 440 degrees I hear the fan speed increase and the roaster loses heat / roast stalls out.

Short Answer: The thermal cut-off kicked in. Read on…
There is a thermal cut off switch that prevents the roaster from getting too hot. It’s a safety precaution, and every home roaster has something of the sort … even air popcorn poppers have them. Sometimes it can stop the roast from progressing, for about 30 seconds ( it turns off the heating coils), but then the roaster will rapidly come back up to temperature. When it recovers the roaster will reach a higher temperature than the first thermal cut-off event, but it will, once again, activate at some point.
I have tested many units to find the real-world temperature cut-off point, and there is a range between 440 (only 1 tested that low) and 465 farenheit, measured with a bean probe.
We have a whole video dedicated to roast curves that touches on the activation of the thermal cut-off … in short a gentler roast curve will not trigger the heat loss until a higher temperature, and is a way better roast curve for quality coffee. Here’s our video on roasting darker and other adjustments.
That said, Popper is not really ideal for super dark, full-on rolling second crack, oily bean roasting. We try to highlight this right off the bat in the SM product description … it’s literally in the intro text to the Popper roaster. Super dark roasting is best done on a stovetop or in a barbeque, since there are no controls to limit you at all. But please be careful – you are literally on the verge of ignition with those kinds of dark roasts
There is a way to easily adjust the position of the thermal cut-off sensor to a higher position on the roast chamber, meaning it will kick in only at a higher temperature. My video on how I modify roasters for testing touches on this. It works, but I can’t recommend it since it voids the warranty if you modify the roaster.
If you experience a roaster that doesn’t finish first crack before the thermal cut-off kicks in, definitely check out the video and article about roast curves. If it is still a problem contact info@sweetmarias.com


Roaster Defect Problems

Popper worked fine for my first 2 roasts. The third time I went to use it, I set the fan to High but it sounded different. The speed of the fan seemed to be varying randomly, going up and down in pitch, and the coffee was moving irregularly.

Short Answer: Contact us.
If you used the machine successfully, then noted a difference in the fan, like it was struggling to spin, with the speed going up and down, this is a fan defect. Contact the seller (info@sweetmarias.com) and tell them about the issue. They should issue a return tag to get the roaster back and inspect it, and replace the machine (if it’s in the 1 year warranty, and I am sure it is at this point!) In any case, don’t use the machine.
This issue usually crops up after a couple uses, But we have noted 2 units where it happens after 20-25 roasts.
While it’s a known issue with a small percentage of fan motors, people should be aware that you can kill the machine by allowing chaff to settle around the base …and that chaff can get sucked up from the bottom vent on the underside into the fan area. Keep chaff buildup away from the base when roasting!
Please note that we did have a customer complain of the roaster fan speed going up and down, but it was happening at a regular interval. It was not a roaster problem, but their line voltage shared with other loads. A defect fan will randomly go up and down at irregular intervals and to a different pitch each time!
We will test your roaster if it comes in for return to see if it is functioning okay to spec. or indeed has an issue, and let you know.

The hinge on the chaff collector is cracked.

Short Answer: Fix it if you can…
We check all the machines shipped for box damage, and we actually spent a lot on those cardboard inserts at each end of the roaster to ensure protecting the top end of the Popper.
So the only damage we have found was when UPS punctured a box (it happened) or somebody drops the top when using it. (I have done it myself several times because yeah, I am clumsy, I admit it!) The fact is, you can use the roaster even if the top gets a bit wonky from some accident. I have also repaired hinges I have broken. (I drilled a small hole and inserted a screw to act as a pin in one of them. You could also wire the chaff collector on, which makes emptying it a little harder, but not impossible. I use a vacuum to remove chaff so it mattered little to me when I did it. In any case, there are DIY solutions for this, if you drop the top, including good old super glue.
While dropping the machine or top is not covered by warranty, we might be able to help you out too. We do not have spare parts for the top (long story, but the factory has trouble producing extras from the mold, but we will keep pushing for them).
If you chose to roast without a top, or without a chaff collector in place, theres a couple things to know.
– First – it doesn’t actually seem to impact the roast that much, except for a small loss of heat due to hot air exiting the roaster easier.
-You can also use one of the glass chimneys we sell for air popcorn poppers on top of Popper roaster, in lieu of the top! It actually works well!
-Lastly, be careful of chaff that will now land all around your roaster base! Be sure none gets sucked up into the machine from the air intake vents on the bottom. This is bad for the motor, and could ignite in the machine!

I received my Popper. It does not say “Popper” on the front!

Short Answer: The roaster should be fine.
We have had 2 cases where the roaster was missing the “Popper” name from the front. I can’t explain this, except to say the roaster should be fine! It was a surprise to me, but I do recall they came up short on the outside chassis and had to use every single one they could find for the first shipment. So that might have meant a few of the outside shells were used before the name was printed on them? Well, maybe you have a rare collectors item there…

I went to use the machine and it was just dead. No power. Nothing lit up. No numbers on timer etc.

Short Answer: Contact us.
We had this occur once. I can’t explain it and when we get that machine back we will do an autopsy to see why! Do, of course, try a different outlet before contacting us. If that’s not the problem, email info@sweetmarias.com


Modification of Popper

I want to add a thermometer to Popper.

Short Answer: It’s very helpful, but…
Be aware that it does void the 1 yr warranty if you open up the machine or drill into it.
It is quite easy to add temperature measurement, and useful in guiding the adjustments you make to “profile” the heat during roasting.
Sorry to say that we can’t have people making holes in the machine etc, and honor a warranty. The issue, from the maker’s perspective, is you just don’t know how people will go about doing a modification. Some people are incredibly skilled, others not so much! Most DIY maker types accept this responsibility: It rarely stops them from tinkering with things. I consider myself moderately skilled and have, since I have opened up so many Poppers at this point, damaged several unintentionally despite my familiarity with the guts.
In any case, I show how I add a Rigid SS thermocouple to Popper for testing some units, and it does not require opening up the machine from the base. Still, since people are going to take a drill bit to an appliance in that case, we can’t be sure they will do things right, hence the warranty issue. (“right” means drilling exactly 13.5-14 cm from the top rim, btw).
While its possible to snake a thermocouple in from the top without drilling the into the roaster body, the problem is placement in the machine, how to fix it to a spot. If it moves around, your readings won’t be meaningful. I haven’t found a solution, but let me know if you do!
My video on how I modify Popper units for testing has some info on this.

Can I force this roaster to go darker without cutting out the heat?

Short Answer: Yes but bypassing or modifying the thermal cutout sensor could be risky, and also voids the warranty…
There is a thermal cut off switch mounted on the side of the roast chamber that prevents the roaster from getting too hot. It’s a safety precaution, and every home roaster has something of the sort … even air popcorn poppers have them. If you look into the roast chamber from the top and see a flat area along the side, that is where the sensor is mounted on the outside of the roast chamber wall. My video on how I modify Popper units for testing has some info on this.
Yes, if you open up the machine, it is possible to shift the position of the sensor so it triggers later. Simply moving it to a higher position (half inch or so) up the roast chamber wall means it will kick in only at a higher temperature. My video on how I modify roasters for testing touches on this. It works, but I can’t recommend it since it voids the warranty if you modify the roaster. If you bypass the sensor you have no thermal overheat protection, so please don’t!
Modification is not recommended, potentially dangerous, and voids any warranty for Popper!

I want to record temperatures / roast curves. I was thinking of using Arduino interface. Any tips

Short Answer: Google it.
Yes, people are definitely doing this. Using Phidget / Arduino or other interface for thermocouples. As with air popcorn poppers, all the info is out there. As you know, it voids warranty to to this but Popper isn’t the cost of some of the commercial machines people do this with! As far as handing over control of the roast settings (fan and heat) to a computer, ie automated roasting, I personally wouldn’t do that, but of course people do. Logging temperatures, being able to see live roast curves, and making adjustments yourself using your own judgment and experience is, I feel, the best of both worlds …

2 Replies to “Having an Issue? Popper Troubleshooting Tips”

  1. Hello there! I have had my popper now for almost exactly 1 year! I’ve done plenty of roasting with it and have overall been pretty satisfied with the roast quality / convenience / and price. I turned on my popper today for another roast and noticed nothing happened.. waited a bit and checked everything to make sure it wasn’t operator error. Then I started smelling electrical burning and smoke emitted from the popper’s coffee chamber. I quickly unplugged it, and it continued smoking for a little while. Sadly I do believe that was the end of some electrical components inside there. I’m not comfortable trying my luck to test it further. I’ve loved the machine, but only 1 year of only semi-frequent use, and then potential electrical fire, I’d have to say the overall build quality needs to be tightened up a bit. I’m sad to see it go, but I don’t think I would buy it again with the potential for those issues. It’s a fantastic idea and I wish you luck on improving the product further!
    Thank you!!

    1. It sounds like the fan might have jammed. Sometimes a good thunk will free it. I agree there is room for improvement and the focus has been trying to upgrade the fan motor. We want to develop a kit too, so one like yours can be repaired. Thats in the works

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