Remembering the Melitta AromaRoast Home Coffee Roaster

Melitta AromaRoast is a little time capsule … a 1980’s attempt at making home roasting something for the masses. It didn’t work well, didn’t sell well, and was a liability in the end.

About 1984, the coffee brewer maker Melitta released the first fluid bed coffee roasterA machine for roasting coffee. Or the person operating it! The basic requirements for a coffee roaster are a heating element that gets suitably hot and a mechanism... designed for widespread use in the U.S. market. Soon after, it was pulled from shelves and the entire production stock sold off. I used to find them as NOS -“new old stock”- a Big Lots stores. They were about $8 if I remember. Recently Dan found a couple floating around Seattle area. They are out there, on Ebay etc.

The history of the machine, and the reason a major manufacturer would make a home roaster at all, might seem incongruous with today’s thinking.

Next Big Thing? Nah!

Perhaps there was an idea home roasting would become a big thing, because Melitta wasn’t the only company interested. Siemens from Germany had the Sirocco roaster, and West Bend tried to produce a home coffee roaster too. 

I think the home appliance manufacturers realized that roasting would be a niche market, and broad appeal would be limited. The main reason is smoke and chaffChaff is paper-like skin that comes off the coffee in the roasting process. Chaff from roasting is part of the innermost skin (the silverskin) of the coffee fruit... that made it unwelcome in the average kitchen. But there was always inherent risk: roasting coffee is not like other cooking or baking. In coffee roastingThe application of heat to green coffee seeds (beans) to create palatable material for brewing a great cup!: Coffee roasting is a chemical process induced by heat, by... you are heating the material, green coffeeGreen coffee refers to the processed seed of the coffee tree fruit. Coffee is a flowering shrub that produces fruit. The seeds of the fruit are processed, roasted,..., to the edge of ignition. It takes focus and attention … there’s no “set it and forget it” with home roasting. 

On top of all that, there was also the issue of a certain patent troll, who was intimidating manufacturers and distributors with the threat of lawsuit. But that’s a different story. 

How Good is the Melitta AromaRoast at Roasting Coffee?

So if you see a Melitta for sale, should you snap it up? Well, if you’re looking for a decent home coffee roaster, there are much better options … like most any other air coffee roaster, or most air popcorn poppers ever made. 

Why? The 1000 watt Melitta Aromaroast was way under powered, barely able to roast 50-70 grams. That’s barely enough for a single 8 cup pot of coffee. Dark roast? I doubt it. The Melitta struggles to get to a medium roast in under 12 minutes. It’s more of a coffee baker. Like a popcorn popper it has no cooling function. 

On the plus side it looks cool in that 70s-80s way. It doesn’t have heat control but has a unique air flow lever that (sort of) allows for some roast control. The metal chaff collector is kind of nice too.

But mostly the experience of roasting on an Aromaroast is just trying to get the coffee brown at all. It’s a struggle to get it to first crackFirst crack in one of two distinct heat-induced pyrolytic reactions in coffee. It is distinguished by a cracking or popping sound in the coffee, and occurs between 390... at all. But here are basic instructions to roast coffee with the Melitta Aromaroast, and some tips to modify the process and get better results. 

Summing up the Aroma Roast

What it has:

• An air roaster, blowing hot air through the bed of coffee past a electric heat coil.
• It blows air through a screen. At best it can only move 70 grams of coffee.
• A chaff collector top, that works sorta okay.
• An on-off switch. The undocumented feature (not mentioned in the accompanying booklet) is that the switch also regulates airflow …from fast to slow. When the switch is set on, but to the left, air flow is highest. When you move it to the right, toward the “Roast” label on the machine, the air flow is damped down. Take off the lower part of the base with 2 screws and this louver function is easy to observe.
• A package of 35+ year old coffee is sometimes still in the retail box! Neato!

What it lacks:

• A cooling cycle
• Enough power. It’s only 1000 watts.

Understand the Switch Function and Air Flow

Instructions for Roasting with the Melitta Aromaroast

The challenge with this coffee roaster is just getting the coffee to first crackAn audible popping sound heard during roasting. In coffee, one refers to "first crack" and "second crack," which come from two different classes of chemical reactions.: An audible.... Getting a dark roast …well I wouldn’t try. But I can roast 70 grams of coffee to a light / medium roast without baking it. Here’s what you need to do:

1. Preheat the roaster. You really must pre-heat this roaster for 3 minutes, without coffee in the chamber. Otherwise you will be baking your green coffee, not roasting it.
2. After 3 Minutes of preheat, load in 70 grams to the roast chamber and start your timer. This is about the maximum roast batchOne of the most important variables in roasting coffee, the weight or volume of the coffee being put in to the roaster will dramatically affect the outcome of... for the machine, the most it can adequately rotate in the roast chamber so the coffee doesn’t scorch and roast unevenly.
3. Start with the the “On-Off Slider switch” (the only control switch on the machine) set all the way to the left. That means having the slider nearest the Off setting. This means that air damper under the roaster is open and more air is flowing in. Initially green coffee is heavier and needs full air flow to move it.
4. After 4 to 5 minutes, slide the switch toward the right, toward the switch side that reads “Roast”. This lowers the air flow. The lower air flow allows the roast to retain more heat without blowing it out of the roaster, and will let you get to first crack, hopefully around 7 or 8 minutes. No matter what, the coffee needs to be actively moving so it will not scorch. Scorched coffee tastes bad, and can be a fire hazard too! If the coffee isn’t moving with the switch all the way right, move it back toward the middle until it is! Eventually get it all the way to the right though.
5. Hopefully with these settings you should hear the very first sign of first crack around 7 minutes into the roast process (from when you added the green coffee). First crack is very slow and drawn-out with the Aromaroast, which isn’t a bad thing. For a City roastCity roast is what we define as the earliest palatable stage that the roast process can be stopped and result in good quality coffee. City roast occurs roughly... I found that, based on first crack starting at 7 minutes, I could wind up the roast at 10 minutes.
6. The Melitta roaster has no cooling function, so you need to stop the machine, take off the chaff collector, and empty the hot coffee into a metal collader, or spread it on a cookie baking sheet to cool

Temperatures measured during roasting:

• Using a digital thermocouple probe, I measured the air flow heat at 300f after 3 minutes of preheating with the slider switch set all the way to the right, near the Roast label.
• Adding the coffee, and sliding the switch to the left all the way (before it actually turns off, duh) you will see a temperature drop, and then it will recover to about 325 f at 3 minutes. If you left the switch at this setting, the coffee would just bake forever. It’s not enough to get the roast to progress.
• Sliding the switch to the right, the temperature will start to rise, ad hopefully your coffee is still moving adequately so it doesn’t burn. At 7 minutes I am measuring 360 f as first pop of first crack occurs.
• I end the batch at about 10 minutes and my probe is reading 375
• All of these readings are combined bean / hot air flow measurements, as you can’t really measure the bean temperature in an air roast system like this.

Tips for Using the Melitta Aromaroast Coffee Roaster

• Try partially covering the exit air flow, that is the chaff collector, with some foil to help boost the roast chamber temperature. Obviously don’t cover it completely.
• Voltage: You need strong voltage, and don’t use wimpy extension cords. Don’t use any extension cords in fact. If you have an old house, you might not get the voltage needed, or see a large voltage load drop, and the coffee just won’t roast. At work I have 122 – 124 v and it drops to a max of 119 v. The aromaroast works better at work than at home where I see a drop to 115 when in use.
• Hotter input air temperature: You can also place the roaster in a bucket or box that baffles the hot air leaving the roaster, and recirculates it into the air intakes at the bottom of the roaster. Obviously be safe about this … but a partial enclosure around a hot air roast usually helps. People use this trick to roast out in a garage in a colder winter climate, for example.
• Roast the right amount: Don’t roast less – less coffee allows more heat to blow by. A bit more coffee helps trap the heat. Too much coffee will not rotate, will scorch and if left unattended, can truly burn.
• If your coffee isn’t actively bubbling and churning in the air flow, stir it with a spoon until it is.