announcements - popper*

August 10, 2023September 16, 2023

Replacement Motor Kit Update

Replacement motors are available at Sweet Maria’s now (June 2023)

Finally, the replacement motors for a DIY rebuild of the Popper coffee roaster are here. I created a video on Sweet Maria’s you tube, and there is more information, plus the link to get a kit, on the SM Coffee Library page. And here is where you get the motor kit for $5 .

Listed instructions from the Video Captions

If it’s helpful, here are the instructions listed out, as they are shown in the video. If there is extra clarification you need or a photo that would be helpful, please comment and we will try to add that.

1- remove the 4 rubber feet to reveal screws beneath.

2- remove the 2 larger front face screws with the No. 1 driver.

3- remove the 4 screws under the rubber feet to release the base from the body shroud.

4- separate base from shroud gently tilting at angle toward the the ribbon wire

5- disconnect ribbon wire and put the body aside.

6 – remove thermal switch connectors and remove insulation jacket.

7 – remove 3 screws holding roast chamber assembly to base plate

8 – remove 3 machine screws holding white fan shroud to metal roast chamber.

9 – remove 3 ceramic spacers to prevent damaging them.

10 – pull the fan off the splined motor shaft

11 – remove 2 small motor mount machine screws – motor is free now

12 – pinch the insulation above the spade connector to help release, while gently pulling side to side and upward.

13 – apply the 2 strips as in the video, not covering any openings in motor casing

14 – insert motor back into white housing, lining up holes in motor with where the 2 mounting screws will go.

14a – (oops) reattach motor with 2 screws, and tighten while pushing motor in place from the back. Don’t overtighten…

15 – push fan down with firm even pressure. test that it moves smoothly

16 – replace ceramic spacers. (added: These are very important to hold fan and heat coil in proper position!)

17 – replace 3 machine screws holding metal chamber to white motor mount.

17a – (added: You will be connecting the red and black wires on the new motor back to the PCB board exactly as they came off; black wire on the lower connector, red wire on upper connector. If you reverse these the motor functions but cannot roast much coffee because (I am pretty sure) the fan will be spinning backwards!

18 – slide thermal jacket on and re attach connectors to thermal switch, pinching them on if they feel lose at all. (added: if they seem loose at all, crip them on a but with pliers. If they aren’t well connected, full power is not getting to the heat coil, and your roasts will take too long / bake.)

19 – Inverting popper, attach base to chamber with 3 screws.

20 – reconnect ribbon cable.

21 – Reseat the shroud on the base, keeping one hand in top hole of roaster to guide it. Don’t force it!

22 – Replace the 2 larger front screws and 4 screws under the rubber feet, and replace rubber feet.

23 – Test your work… hopefully that motor purrs at an even clip and you have 250+ roasts more…

June 7, 2023June 7, 2023

Repair motors for the Popper coffee roaster have arrived

For those willing to replace their old dysfunctional motor with a new one, a 20 minute task can result in new life for the Popper coffee roaster

Here’s a quick update that the motors are here, and we can prepare to send them soon once we have assembled the small kit and made a step by step repair video.

Swapping the motor out is pretty simple, a 15-20 minute task. But doing it with some care can have a much better result than rushing through it. So we will get a good video together to guide through the process to get the best results!

November 12, 2022

Popper Roaster after Christmas

Delays delays until after the holidays

The latest update is that, unfortunately, we won’t have a supply of the Popper coffee roaster until after the holidays. We tried to get it here. But the priority in manufacturing and shipping favors big appliance brands. A small project is put last.

We are also looking on fan motor upgrade kits, which can bring a Popper back to life from the verge and/or extend its useful life. More details on that to come…

June 7, 2022

Out of Popper

It’s not easy to keep things in stock these days …

So you might have noticed the Popper coffee roaster is out of stock. We have some units in reserve to cover any issues / replacements, but don’t have any to sell.

It’s pretty easy to guess the reasons, but just to state the obvious … this big rats nest called the global manufacturing and logistics network is very hard for a small business to negotiate these days. Parts aren’t available and time lines keep changing.

We are taking this break to make any changes we need in components. The plan is really not to “upgrade” what we have, add function (which always adds cost). But instead to improve the durability and % of units that come off the line with a quality issue.

When you manufacture something the accepted rate of defect is 1.5%. That could be one of the many components, or the assembly itself. We actually came in way below that with assembly defects (and we replace any problem units promptly as our buyers will know). But we want to improve some components in terms of durability, specifically a better fan motor.

So that’s where Popper is at, and the focus of the project. Look for updates when we are in production again, which should be fairly soon.

In the meantime, Popper is 100% supported, so send any questions about operation or to report any issues!

October 3, 2021October 3, 2021

Popper Deconstruction: Inside an Air Coffee Roaster

A very basic video about making and testing Popper, the air coffee roaster.

Here’s a video to show a few early versions of the machine, and some aspects I had to deal with in getting this project completed.

I don’t think this is a video of general interest so please don’t expect much, and the quality isn’t great. I was trying to move the camera phone around to show details and didn’t always do a great job. Ugh.

Also I need to make it clear that you shouldn’t do what I do here, because opening up the machine voids the warranty against manufacturer defect. I made the video to provide some background details only, and show how I test temperatures.

Some things I go over here are
A look at an early prototype
Location of the thermal cutout switch that protects Popper from overheating
When I have a unit that turns off before reaching dark roasts, how i move the thermal cutout switch upward to solve the issue.
How I use a thermometer to probe the bean mass
Show a bare version with probe locations for input air and bean temperatures
Deconstruct (partially) a Popper to show how it’s put together
Talk about the unit that easily roasted 140 grams, and why I couldn’t get it built that way 😢

PS – this is in my workshop space where I store the pallets of Popper, hence the motorbikes and cars and such.

Inside Popper Coffee Roaster

March 4, 2021March 4, 2021

Some things take time, like manufacturing a coffee roaster …

popper*, the coffee roaster was right on the verge of going into production.

… but one thing just wasn’t right. The factory had sent sample after sample, but the fan speed (and therefore the air flow) was not consistent. This impacted the potential batch size.

A late night video chat with the engineers in China made it clear to me though. They were testing under the principle that the roaster should not use the entire pre-programmed roast cycle of 7 minutes. They thought of 0 to 7 as a range so they were presupposing what I wanted was a 4 minute roast!

Well, a 4 minute roast is easy in a popper, but it’s rarely an ideal roast time. In fact, the whole idea of *popper is that the user can fluidly adjust roast time up or down on the fly. It’s a manual, low tech machine, unless you want to get in there with an arduino interface etc.

It’s a machine that rewards people who want to play around with the variables, so it’s simple to do a 7 minute roast just to first crack and add 2 or 3 minutes for development. You just have to be there and tend to your roast, make intuitive decisions and turn a knob. Simple.

(For me I actually feel the 7 minute pre-set roast time can work very well. For City roast I target 5:30 to hear the start of first crack, and the remaining 1:30 for further development. Remember, roast time is relative to the device and the type of thermal transfer. Higher air flow and more movement of the mass means more rapid levels of heat transfer via convection.)

November 10, 2020November 10, 2020

Let’s call it February …

Popper* will make coffee go pop, but probably pop corn too. And it is coming along nicely. No need to rush to get it made before Christmas, because it needs to do what it’s supposed to do. It’s going to be February I think.

The prototype samples were going well except in one regard: Each seemed to roast a little less than the previous. We ended up with a final sample straining to move 85 grams of fresh green coffee. No!

So we delayed production to balance out fan and heat and the roast chamber vents. I worked on the exit air vents thinking they were constricting flow … but it turned out it was the inlet air vents. And just minor tweaks made big changes in batch capacity.

But those changes impacted the heat curve too and, while I could roast 140 grams, too much heat was blowing by the coffee and out of the roaster. I couldn’t get darker roasts within a single cycle. (I could by adding time, but we need dark roasts to be in closer range).

So now, fingers crossed, last set of prototypes are on the way with new fan speed, and an additional set of roast chambers, 5 in all, to find the best combination.

I think this is it! What I want is a 120 gram target that makes use of the range of air and heat settings, allowing manual profiling with extended roast times, and full roast range.

And with that, I’m able to get some really striking profiles that don’t at all taste like fast popcorn popper air roasts. Low heat warm-up times, ramping up to first crack, and backing off to finish the roast with control. The 10 minute roast profile I did yesterday of Guji Uraga Hare Wato was really the best roast I have had of that coffee. Really fantastic, sweet and floral.

June 2, 2020

What’s in a Name? Not Much.

Popper the Roaster Logo Name

So we had some clever names, and over time none of them seemed right. We ended up with a name which is okay, likely not the best. It’s not clever or funny, unless it’s funny in a bad way, like ha ha that’s dumb. But in the case I think it’s okay to be dumb.

I have product fatigue. I am tired of new versions of the same old thing. I am tired of being a consumer and tired of feeling duped. That likely will never end, I am a sucker and I supposed most people are, just at varying intensity levels. (?)

Anyway, you have to give something a name it can be called. You have to “market” it at least to the degree it is being “brought to the market” as a thing to sell, and it needs some name to distinguish it from all other things. We could just point and say “that thing” but it might be confusing.

So there’s this mental exhaustion I have brought on by nearly all shopping except just repetitive grocery type trips. And even those too …for example, walking down the beer aisle at your basic fancy store, and just being tired of all the labels trying to have “personality.” *

I know, ironic since we have a site (ie sweetmarias / coffeeshrub) with a bunch of choices and long reviews and exhaustive descriptors.

So yeah, Popper* and an explanation “popper is a coffee roaster.” I guess for me, 20+ years in home roasting business, there has been some dry (very very dry) humor in pointing at a popper and calling it a roaster. So I started to write popper-roaster, or air-popper-roaster, or air roaster, but appreciated that someone who had no context to understand what it refers to finds any title confusing.

So I guess Popper as a name just ropes in that confusion and claims it.

The other funny thing is the name is too common to be a trademark. Not that we are just saying “yeah, copy us, open source.” I feel like we own this project and put a lot of time and money into it. It’s not cheap for tooling and such in manufacturing.

At the same time, it’s a popper! We didn’t invent that. We weren’t the first people to roast coffee in an air-popper-roaster. We made a lot of small decisions that resulted in this thing, but it’s not that big a deal.

And as it sits it is not the ultimate coffee roaster. It just works well, costs less, is basic and easy to use, and (nudge nudge) it could be made more interesting as well by some clever people in the internet world.

We did our part. Here it is. Well, soon, like probably Oct-Nov 2020.

I can’t believe you read all this! – Thompson

* Things relate as subjects, people relate as objects. This is the basic notion of Commodity Fetishism. It’s the way, for example, cars have “Stance” or “Character” in advertising. And in the world, on the road, express the Taste, Character or Class of the owner. But the person themselves is mute, as an object.

May 22, 2020June 2, 2020

Sumatra And Popper

Sumatra from Aceh area isn’t that low grown generally (1250 to 1800 meters) but can be tough to roast. It often gets a heavy, dark roast treatment that obscures the coffee to a point. Lighter roasting is more challenging.

Air roasters do a pretty good job with this. It’s hard to scorch coffee in an air roaster … provided you don’t overload it.

Currently we use a 3 barrel Probat for samples but when I have a single sample to check out, I’m using Popper lately.

Here is a 1450 meter Sumatra from Aceh (near Lake Takengon) roasted for cupping in Popper.

Lighter City roast from the popper for cupping and drinking!

May 8, 2020

Origin Story #1

We wanted to create a coffee roaster, one that was a lot like a popcorn popper from the ‘70s. We didn’t want to think up any new design, or new roast method. We wanted to take what works, the air popcorn popper, and roll it back to the way it was 30 years ago.

So we took an old vintage air popper machine we bought at a thrift store in the ‘90s for $4, and sent it to China. We sent it to the factory that still makes air poppers, and asked if they could make one just like that. They said they could.

West Bend Poppery, first version, 1500 watts

They sent us back a prototype machine. It looked just like the popper we sent them. Actually it was the popper we sent them, but they added 2 knobs to the front.

From then it was a long (and actually pretty boring) back and forth between Oakland and the factory.

There’s more to tell… but we are trying to drag out the story and make more “content” out of this.