Popper is a Coffee Roaster: Information and FAQ page

A review of a new home coffee roaster called Popper; moderately priced, manually controlled.

We are excited to launch a new home roaster that offers roast control at a moderate price. It’s a great option for those who what to upgrade from air popcorn poppers, those who want to try coffee roasting for the first time, and some experienced folks who want a simple, intuitive way to roast their coffee.

Popper, as the name makes pretty clear, is based on the hot air popcorn poppers so many people use to roast coffee. Unlike those popcorn appliances, Popper allows user-control of the heat level, fan speed (just high and low really) and the roast time. These can all be fluidly adjusted during the roast cycle. (And in case you are wondering … Popper can pop corn too, not that you would want to!)

The capacity is 100 grams, which equals 3.5 ounces or 3/4 cup by volume. You can check out Popper on Sweet Maria’s shopping site

Popper Coffee Roaster Front View

Not high tech … but easy to operate and user friendly

Popper has no automated roast cycles, beyond a default 7:00 roast and 3:00 cool. You, the user, can “profile” the heat curve and set roast parameters using the front control knobs. But nothing is “preset” for you. If you want a roaster that saves programs, has automated roast curves, or connects to your phone app, Popper is not for you.

Turn on the Popper and you see 0:00 on the timer and a green light – the Off position. When you start a roast batch, the maximum time allowed will read 10:00 on the digital count-down timer. But that is not 10:00 of roast time. The final 3:00 on the timer is the cooling cycle. During the roast the light is red, and when the timer reaches 3:00 it turns blue for cooling. So yeah, you gotta do a little math: 5:00 on the timer clock means you have 2:00 more of roasting and then 3:00 of cooling. You can handle it!

The nice thing here is, unlike some other roasters, you can use the time dial to add and subtract roast time during the roast whenever you want. Even if Popper goes into cooling mode, just turn the dial above 3:00 and you can roast more.

In other words, Popper is pretty intuitive for you to control. It’s not high tech but -pretty ok in terms of human tech. And we still think humans controlling and making decisions about the roast process is the best way.

A Quick 2:00 Popper Roast Run-through

Popper is a coffee roaster, a quick 2:00 video run though
Want to see Popper roasting in more depth? See our 2 Part Popper Roast Demo Video.

Popper Quick Start Guide and Safe Use Instructions

Popper comes with some printed guides to get you started and offer safe use advice. Here are some image highlights, and the full PDFs are linked below-

Popper PDFs

These come with the machine, but here are printable PDF versions in case you misplace them

A Quick Note on Agitation!

Not emotional agitation, nor political agitation … we’re talking green coffee agitation. In air roasting it is really important that your coffee moves, right from the get-go. Here is a quick clip showing good agitation versus more “marginal agitation”. I would make sure your coffee is moving no slower than the “marginal” example here. But even if you need to back off your roast weight by 5-10 grams, it’s best if it looks like the “good” example!

Popper is a Coffee Roaster -Image Gallery

Popper FAQ – Your Questions Answered…

What is the electrical rating of the Popper coffee roaster?

The Popper is 1200 watts. The heating element is 1150 watts and the fan is 50 watts. The fan is DC, while the element is AC.

Popper is UL listed for safety.

What are the dimensions of the popper

7.5 inches deep x 7.5 inches wide x 15.75 inches tall. The base is 12″ tall. It is larger than typical air popcorn poppers. This is to make it stable and accommodate the increased height of the roast chamber.

How much green coffee can you roast in a batch with Popper coffee roaster ?

Popper batch size 100 grams cup measure

We recommend 100 grams (3.5 ounces). In some cases you might want to reduce this to 90 or 95 grams, if the green coffee is not moving sufficiently when you start the roast. You can always check whether there is too much coffee loaded in the roaster by running it in cooling mode a few seconds. Fan speed in cooling mode is same as fan speed on High during roasting.

Our experience is that after a few batches, you will see a new machine start to rotate 100 grams easier. In fact we have had units where we can increase the batch size because of this. I think it’s due to some “seasoning” of the roast chamber surface after a few batches that makes it “slicker”, but I am not really sure!

OOPS: In our printed instructions we say you might roast up to 140 grams. That’s likely not the case, but you can roast more that 100 provided that the green coffee is spinning right off the bat when you roast! The 140 grams was from a pre-production unit running on a 123.5 AC volt line. Note that different size beans and coffee density impacts roast batch size. The important thing is that the coffee is rotating in the chamber so it roasts evenly. Also, we notice that when a machine has been used the potential batch size seems to increase slightly, based on how much green coffee it can rotate. We can’t completely explain this though. Here is a video shows good bean movement in Popper.

Can I use an extension cord with Popper?

No, you really shouldn’t. Extension cords aren’t safe with higher wattage appliances, especially thinner gauge indoor type cords. Extension cords can also deliver lower voltage to the Popper so it won’t perform as it should.

Can the Popper roaster be used indoors? How about outdoors?

Yes. In fact it is not intended for outdoor use. But in fact most people will roast on a porch, in a garage or somewhere other than a kitchen. The reason is usually because of the intense smell of roasting (especially darker roasts) and the small bits of chaff can escape the roaster during use. Popper’s chaff basket definitely allows some small bits of chaff through, but unlike a popcorn popper that just blows out the chaff, it does catch 95%+ of it (roughly).

Popper is not intended for outdoors because it should not be exposed to the elements. That’s why roasting on a porch, covered balcony, garage etc seems to be the best place.

What is the warranty on Popper?

The maker (Agnes LLC) offers a 1 year warranty against manufacturer defect, so this includes any failure that occurs do to a bad part (fan, heating element, etc) provided the machine has been used according to the instructions that come with it, and those spelled out in the User Guide / Safe Use Instructions (i.e. not for commercial use etc). The warranty doesn’t cover misuse, dropping it, etc. Contact [email protected] with any issues or questions.

Why aren’t there numbers on the Heat level knob?

Front Panel Explained - Popper Coffee Roaster

It might seem like an oversight, but the lack of lines and numbers is intentional. The short answer is that your roast set to “2” for 7 minutes is not like Joe’s across town or Julie who lives in a 1930s apartment or Jack who roast outdoors in the Colorado winter.
Line voltage, voltage drop, environmental temperature – this and other factors makes one roaster different than another, even when all the heat dials are set to 2 or C or Medium.

What I like to do is make my own marks on the heat knob for settings that work for me. We also include a sort of “template” in the printed material with Popper you could use to add a scale to the knob, if you want to.

Anyway, there’s way more to say on this, but we thought it best that YOU create marks on YOUR roaster so they actually mean something to YOU! That is, if you really want marks. I’ll going deep into this in a separate post.

Do I need to weigh the green coffee for each batch?

green coffee volume measurements

Yes you should …but you can roast by volume instead of weight, by using a scoop or other measure of your choice. Green coffee types vary by volume more than weight though, but we find that 100 grams = 3/4 cup = a heaping 1/2 cup measure (as pictured). It is better to use weight measurement for accuracy though.

No matter how you prepare your batches to roast, two things are very important: 1. Don’t roast too much coffee: the coffee should move when you turn on the roaster. If it doesn’t it will scorch. 2. Be consistent with how much you roast. Weigh or measure the exact same amount each time. The green coffee batch size is a big variable in roasting, and your roasts will be inconsistent and unpredictable if you vary the amount of coffee you roast. This video shows good bean movement!

PS: In our printed instructions we say 3/4 cup = 100 grams. It does – a wide heaping 1/2 cup measure as pictured = a level 3/4 cup!

My roasts are too fast with Popper!

It’s entirely possible to roast too fast with this machine. There won’t be anything wrong with the coffee per se but super fast roasts aren’t usually the best tasting. You should not use the highest heat setting ( 3:00 position) generally. In all my testing, with appropriate line voltage, I have never had to use 3:00. In fact even 2:00 can be too fast, at least for the entire roast. But this depends greatly, in the case of air roasters, on what you are plugging it into, where, and ambient conditions. In any case, that’s why Popper gives you control of heat, to start out at 2:00 for example, reduce to 1:00 as coffee yellows, and drop to 12:00 just as first crack starts (and for me that’s been a good roast strategy generally).

What is the Low setting on the fan for?

Low setting doesn’t always come into play when roasting. I do not use it when starting out a batch, as I usually want to be sure the green coffee is rotating initially so it heats evenly in the early stages. You could use Low if you only have 50 grams to roast for example. But that probably won’t be the case often.

Low fan setting is very useful later in the roast though, for people who want darker roasts, or find their roast has stalled and isn’t progressing. It might seems counterintuitive, but Low fan speed will heat the roast batch to higher temperatures, because less heat is being pushed past the coffee and out of the roaster.

What’s with the name “Popper”?

The idea was to name it what it is, a popper with features. It’s better than GloboCorp TurboRost 5000 (Hmm… wait, that would have been pretty good too!)

The makers of Popper literally sent the best air popcorn poppers to engineers to try to replicate what the old first-generation poppers could do. That’s because the current poppers on the market are pretty weak. And now those old 70s air poppers are selling for $50-60+ on Ebay. The idea was that the home roasting community needed some better material to work with, and something not super high priced. At the top end, there are options these days, but not so much at the affordable level. If you want an app, get an Ikawa!

Can Popper be used without the chaff collector, or without the whole top hood?

Definitely, and if you roast somewhere the chaff can just blow out into the environment, you might prefer that. The advantage is improved visibility of the roast, and you can hear the cracks better too. I also use a long wooden spoon to simply reach down and pull out beans to during roasting!

The drawback on this could be that more heat is escaping the roaster, so roasts are slower, or don’t progress. The hood and chaff collector help to restrict some heat from leaving the machine. I use one unit with just the transparent hood and no chaff basket, and during the roast I remove the top to inspect the roast, and replace it. Works well for me…

Can Popper be used with a glass chimney instead of the top hood and chaff basket?

Definitely, and if that’s the way you have been roasting with a air popcorn popper, I think you will find the same glass chimney fits the Popper roaster too. (Such as the one SM stocks).

Can I add a thermometer to Popper?

Yes it is quite simple to install a thermocouple type thermometer. SM sells a sheathed stainless thermocouple and a digital thermometer that is well suited for this purpose.

Can I pop popcorn in Popper?

Popper can pop popcorn

First things first … yes you can!

Should you? No. Plus switching between coffee roasting an popcorn popping would mean your coffee tastes like popcorn and your popcorn has coffee roasting residue on it! 🤢


The timer in the photos has a maximum of 10:00 minutes. Can it go higher?

No, 10:00 is the highest value and it goes to cooling cycle. But that doesn’t mean you can’t roast longer! You simply add time during the roast to extend the roast time. You can surely do 10:00 or 12:00 for example.

The default maximum timer setting is 10:00. So can I do a 10:00+ minute roast?

You can! That initial 10:00 on the timer means 7:00 roast and then 3:00 of cooling. (The count down roast timer always includes those last 3:00 as for cooling).

To roast longer than 7:00, such as 10:00 roast time, you simply add time using the knob once the roast has started, and at least 3:00 has elapsed. You can add time to your roast as often as you want to continue extending it.

If the default roast time is 7:00. Is that a good amount of time to produce a quality roasted coffee?

Yes, when the timer reads 10:00 that means 7:00 roast plus 3:00 cooling cycle at the end. In our experience 7:00 is indeed a good roast time for an air roaster such as Popper, though we have done some really nice extended roasts of 9:00 to 12:00 range. It depends on the coffee and of course, how you adjust the heat along the way.

To be clear, just because 7:00 is the initial roast time, that doesn’t mean we think that’s what you should use all the time. We have done faster roasts that are great, but when roasts finish below 5:00 they start to have a certain taste that doesn’t seem to maximize coffee sweetness. Their can be some green or grainy notes because of the bean interior being roasted much lighter than the outside. It can look fine, but the roast taste isn’t at it’s best. We like the City roasts when first crack starts at 5:30 into the roast (that means 4:30 on the count-down timer!) and then 1:30 of further development. That’s a 7:00 roast in total that works out well. We also like an extended roast with a slower warmup phase, targeting a 7:00 first crack (that would mean 3:00 on the Popper clock, right when cooling kicks in) then extending the roast 1:30 to 2:00 longer for further development.

Why is the clock / timer limited to 10:00? Why does it count down, not up?

First, the 10:00 timer does not mean you cannot roast longer! But to add time to the roast, you can’t exceed 10:00. It was hard to get a design that would pass the engineers approval and UL approval, yet allowed for full manual control of the roast. By that I mean allowing the user to fluidly add time or change the heat and fan levels at any point in the roast. If it had unlimited time, beyond 10:00, someone could add say 30:00 and walk away! The way to make the roaster safe, in case someone forgot they were doing a roast, was to make in count down and shut off. Other roasters have an “unattended roaster” feature (Behmor, Bullet) and if you don’t hit a button, the roaster goes into cooling. When that happens, you can’t save your roast by going back to roasting, like you can with Popper. We had to come up with a safe way around that, but allowing the best user flexibility in a clear and simple manner, and this was it!

Is Popper good for roasting espresso?

Yes, we think it is, and certainly better than air popcorn poppers. We think better espresso profiles are slightly longer roasts where the interior and exterior of the bean are developed more evenly. In fact, brewed coffee can be better when there is some degree of difference from inside of the bean to outside, making for a brighter more dynamic cup. But espresso seems to like more parity between exterior and interior. And the fact is, air roasters generally are not the best for creating that type of parity. But with Popper you can extend the roast in a way that can, so for batches intended for espresso we suggest an extended roast time, slowly developing the coffee through the yellow and brown stages, targeting first crack to start at 7:00 to 8:00 and finishing the roast at 10:00 to 13:00, depending on the roast level you are seeking. Always rest batches for espresso longer than brewed coffee… 48+ hours or more!

I can’t see easily through the roast through the hood…

Overhead light source - Popper coffee roaster

The transparent hood is actually tinted a bit yellow (there was no way around this, it is a special high temperature plastic). Even after a couple roasts it can attract some roast residue that makes seeing through it a bit harder. When it is still warm, wipe it with a soft towel. After roasting you can hand wash it with soap to if you like, but do not use any cleaning pads or abrasives!

To see through the hood, the best way is to use a strong LED overhead light. It is amazing to see how a good directional daylight-balanced source can help you see the roast! I don’t recommend it long term, but a decent phone LED light placed on the hood for a few seconds will give you a good indication how much directed light helps.

Another idea (not for everyone) is to go hoodless. Or my version … leave the hood unclipped when roasting and remove it using the small handle in the rear. Removing the hood will bring down the roast changer temperature a little but it doesn’t have a huge impact on the roast process in a cyclonic air roaster like Popper.

I can’t hear the roast over the sound of the fan!

Popper isn’t the loudest roaster. It’s not the quietest either. I don’t have issues with hearing first or second crack in popper, but we know customers who have trouble with this in other air popcorn poppers. (We had a cool prototype version of it that roasted 140 grams, not just 100 – but the fan speed required to do so was incredibly loud. We couldn’t hear the first crack either! Plus the engineers thought the fan couldn’t take it, over time). I don’t have a solution for this, as all air roasters have an issue with hearing the cracks. But I have found some rooms that reflect more sound make it harder to hear. So location might matter on this issue.

Do you have a question or comment?

Contact us and we will answer it in our FAQ!

I was roasting and heard the fan sound change a little, and the roast stopped progressing. What is that?

Popper has a thermal cut out switch. If the roast chamber temperature gets too hot, this could kick in. It cuts out the heat to the electric coil temporarily until the roast chamber temperature comes down. This can take 20-30 seconds. You can avoid this in your roasts by slowing down the roast process. Don’t roast at high temperatures too fast (which isn’t a great roast technique anyway) and the thermal cutout switch should not be an issue.

If it continues to be a problem there is a fairly easy way to re-position the sensor, but this involves opening up the machine so we can’t recommend it.

My roasts are too slow!

There are a few ways to speed up roasts, most obviously to increase the setting on the heat knob. But you can also see an increase in roast chamber heat by changing the fan speed setting from High to Low. This increases the heat because less hot air is being blown past the coffee and out of the roaster. But we prefer only to do this later in the roast when the beans have lost weight and are moving freely. Low fan speed at the start of a roast will usually not agitate the green coffee effectively.

If your roasts are too slow or aren’t getting dark, it might because of low electric line voltage to the machine. Don’t use extension cords! And try another outlet closer to your electric panel / fuse box.

It also might be due to cold ambient temperatures. There is a big impact on roasting if the air drawn into the machine is frigid. Some ways to address roasting in the cold are to use an open-sided box around the machine so it draws in warmer recirculated air. But be fire safe if doing this!

Is it possible to roast TOO FAST in Popper?

Yes, it definitely is. I see the main feature of Popper as the fact you can take the air popcorn popper type roast and slow it down with the basic controls Popper offers. But in order for Popper to work well, it also had to have the heating properties to roast fast. If it was just super under-powered and forced you to roast slow, that wouldn’t be good.

When we say “too fast” in an air roast like Popper, I would define that as 3:00 to 4:00 roast time. Air popcorn poppers are often known to roast that fast, and Popper can too, depending on the settings you choose and the coffee load you put in. It’s up to you to control the roast from progressing too fast. I address this quite a bit in the longer 2-part Popper roast videos I made.

Can I set the roaster temperature and time and walk away?

You should never, ever walk away from a coffee roaster while it’s in use. Coffee roasting in its essence is drying out a woody plant material and bringing it to the brink of fire. No commercial / professional roaster ever leaves a roasting machine unattended, and you shouldn’t either! While the beginning stages of a roast can progress slowly, called the drying phase, things happen very fast at the end of a roast: each 10 seconds that elapses can produce a different taste result. You need to be there for it!

Can I start a new roast as soon as the previous one cools down?

You can do so, but it will produce less consistent results, and could cause more wear to the machine. It is best to allow the machine to cool an additional 5-10 minutes between each batch, after the cooling cycle ends, and before starting the next batch. This is better for the machine and it means each of your batches will be have a more similar starting temperature, thus more consistent results.

Also, Popper is intended for home use, and to produce a personal supply of coffee. The warranty doesn’t cover you otherwise.

I notice when setting the heat level, the increase as I turn the knob doesn’t seem to be linear. For example the change from 1:00 to 1:15 on the heat knob isn’t the same as 1:45 to 2:00?

Any electric heat control (that we know of) isn’t going to be perfectly linear in terms of the resulting heat change. We need to map out the Popper heat adjustment on the final version, because we too notice some ranges that have increased impact and ones that have less. Another way to say this is that, for each degree of change in turning the knob, it’s not like the heat increases at a constant rate, such as 10 degrees turn = 20 degrees farenheit increase in burner temperature.

In a way this is another reason we did not include marks or numbers on the knob, and feel it’s better if people mark it themselves (I used a dry erase initially and then marked with a black sharpie to record settings on the knob I liked for warmup and finish roast stages. The black sharpie on black can be seen in the light, but isn’t too obvious.) Anyway, number or marks would infer that each change from 1 to 2 or from 6 to 7 would have the same impact on burner output, and that wouldn’t be true for Popper, nor is it for any electrical heat appliance!

Perhaps this is part of the reason some cooks like gas stovetops?

Does the chaff building up in the basket impact the roast?

During a single roast the buildup of chaff doesn’t seem to impact air flow. We checked this with an anemometer to measure air flow and could not see a difference. Between roasts always empty the chaff basket.

If I want to roast another batch after the prior one cools, what do I need to do?

First: You MUST empty the chaff basket between each roast. The chaff basket is only intended to hold the chaff that comes off one batch of 100 grams. Second: You should allow additional time for the machine to cool before starting your next batch. This helps your roast-to-roast consistency, and is also good for the roaster. We recommend 10 minutes between batches, or 5 minutes if you also run an additional cool cycle with the roaster empty.

Can I modify the popper to control the heat source by computer?

Probably, but you do void the warranty by opening up the machine. People have modified air popcorn poppers to be controlled with Artisan software via Phidget or Arduino. There’s a lot of that discussion on homeroasters.org

I am starting a small coffee business. Can I use Popper to roast and sell coffee?

Popper is not intended for commercial purposes. So you can use it that way but it voids the warranty … plus the 100 gram capacity is going to make it challenging to roast coffee for others. It’s made to just supply you and your household with coffee!

Neal asked, “I was just wondering if you’ve done any stress or endurance testing with it. I know nothing lasts forever and each model may vary, but I’m just wondering how much the estimated lifespan is expected to be?

For example, I’m likely going to be roasting three 100g standard length batches per week in mine. 2x on the weekends with 15-20 minutes between and a supplemental batch midweek. Is a two year life on the roaster probably a safe bet or a stretch goal?

Thanks for this question Neal! The short answer is no, the final production machine it has not been truly stress tested. 

Here’s some better news though … I have been testing this design for about 1.5 years now, and through many prototypes. We had some snags right at the end which led me to test 6 units pretty exhaustively for about 100 roasts, and those were basically made from the final production components. On top of that I hired a company called ITS that’s independent but has full factory access: They pulled random units and quality tested them pretty extensively, which was about 5% of the production. They were looking for assembly flaws and ran roast tests etc. Not stress testing but definitely helped to keep the factory on their toes for QC ! Anyway I feel the design is really sound, and has been proven for years in air poppers, which this factory also makes. The part I fear most for failure in time is the fan, but we chose a better quality part at the beginning of the project to address that.

Anyway, just some thoughts. I feel 2+ years of that kind of usage is very reasonable to expect. I think it will be much more… Popper is based off such a long-standing design, but has upgraded components versus any other modern day popcorn popper. So I expect much better long term durability than those machines…

Is there an app I can use to control the roaster?

Maybe. Let us know if you find one.

Where is Popper for sale now? You can check out Popper on Sweet Maria’s shopping site .

6 Responses

    1. The hood is the main part we wanted to have spares of but our first shipment did not include spares. With popcorn poppers used as coffee roasters, the hood often is an issue, and warps or even completely melts. Thats because they aren’t made for the sustained heat of coffee roasting. This hood is designed for coffee roasting though, so it can take the heat without warping etc… just FYI

  1. WOW! A controllable popcorn popper for roasting coffee. I’ve been home roasting for over 20 years now and would’ve loved to have this back in the day. Roasting with the old poppers was a labor of love that lead to a welcome divorce when I got my first Behmor Drum Roaster. I’m so excited to rekindle that love and receive my first controllable popper. The novelty air roaster worthy of showing off. Thank you.

    1. Thanks – yes in a way it’s a very basic roaster. Nothing new here. But it takes something that has proven to work, air popper roasting, and hopefully fixes the issue with unmodified air poppers. That is, they usually roast too fast, and there’s no great way to control them.

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