Home Roasting FAQ

Over the years I have responded to countless emails from folks who want to start home roasting and are not sure how. I have also fielded an untold number of messages from folks frustrated with their roaster, either because the results are not what they expected or there are mechanical problems. So I thought I would put forth some thoughts on both topics. - Maria

Q: Why would anyone want to roast their own coffee?

A: Freshness is a huge issue with store-bought coffee - the cup quality of coffee declines quickly after roasting. After 5 days the aromatics of the coffee are fading, and after 10 days there is a drop in overall cup quality in most roasts. Lord knows how old the big-brand coffees sold in supermarkets and cafes truly is. Also, home roasting lets you control the degree of roast, to customize the coffee to your liking, as well as choose from a vast array of green coffees. Green coffee, unlike roasted, is quite stable and will not have a drop in cup quality from about 6 months up to 1 year from arrival date (every coffee we sell has an arrival date in the review). Home roasting is also often cheaper than buying roasted coffee: most of our coffees sell for under $6.00/pound.

Q: I do want to start homeroasting. Do I buy a machine or is there another way? What is the best home roaster?

A: In general there is not one BEST machine, or BEST way to roast - only a lot of different options that you ought to consider and then pick one that seems to fit. There are many ways to roast coffee, from home appliances made specifically for this purpose, to simple pan roasting. Most methods are simple and the results are excellent!

The fundamental choice in home roasting is choosing between a manual method and a more automated method. In both cases, my personal opinion is that the most important thing is to look at the roast itself - and that process is pictured and described on our Pictorial Guide to the Roast Process page. Timing, settings and temperature readings are signposts along the way. The most important thing is to watch the coffee itself and develop a sense of where the roast is by color, smell, sound and most importantly taste of the roast when done. None of the settings on the fanciest, most expensive roaster in the world will help if you do not know to how to judge the coffee itself. (The analogy that comes to mind is how folks spend $$$K on a Viking range but can’t boil water. It is not the equipment that is important.) Roasting, like cooking, is both a science and an art, and developing a feel for the process is key.

Manual homeroast methods using an oven, stovetop popper, skillet or wok (even a heat gun and a dog bowl) are just that - you control the temperature, time and movement of the beans entirely by hand. These are all conduction methods and result in a slower, more full-bodied roast. Roast times will be in the range of 10 to 20 minutes and you can roast up to a full pound in a stove top popper (though Tom prefers working with a half pound batch as it is easier to keep moving).

You can also re-purpose a Hot Air Popcorn Popper (which does a bit less than 4 ounces per batch) and control it manually. This is a fluid bed roast and has more in common with the small machines discussed below.

I think some folks wrongly dismiss manual methods out of hand as too hard. If you like to cook, then a manual roasting method is not that difficult and, with practice, you can get great results. Like making your own bread, when you get it right it is delicious and thrilling - a real accomplishment. Even mistakes are generally tastier than your average store bought loaf or, er, coffee. A timer and/or a thermometer are a good idea for manual roasting.

Benefits of manual roasting are:
low equipment costs (provided you have a stove or oven or a hot air popcorn popper in the cupboard)
direct control of the roast
beans are more visible
higher volume batches (up to a pound)

Problems are:
more labor intensive
less even roast (with stovetop and oven methods)
no automation of temp or time controls
more smoke (more coffee equals more smoke)

Q: I think I want a machine - what should I consider?

A: Home coffee roasting machines do have a niche market because, while folks enjoy good coffee and might even consider roasting, the idea of standing at the stove for 12 minutes stirring coffee is the hindrance. Tom does have a Home Roaster Comparison Chart of the various machines, to compare them in terms of size, cost, pros and cons for each machine.

In choosing any roaster the main issues are how much coffee you generally drink and how much you want to spend. Batch size can range from small in a Fresh Roast (about 3 - 4 ounces) to large in a Behmor roaster (about 3/4 of a pound). Four ounces of green coffee gives you about 5.25 scoops of ground coffee - that is just over 26 ounces to 42 ounces brewed coffee depending on how strong you like your coffee. A HotTop or Gene Cafe gives you twice as much - 10.5 scoops of coffee - about 52 to 84 ounces of brewed coffee. A Behmor can produce 1/4, 1/2 or full 1-pound light roasts. Ideally you want to get a machine that roasts no more than 3 days supply of coffee - unless your schedule is such that you have to roast less often. You can use these home roasters more than once a day generally, but it is not advisable to do so. These home machines are not designed as production roasters and using them to crank out more coffee than they are designed for will not only void the warranty but also burn out the machine quickly. "Serial" roasting on a home machine can also lead to other problems.

Q: What is the difference between air roasters and drum roasters?

A: The smaller home roasters are based on the air popper design for the most part. These are fluid bed machines - they use hot air to roast and move the coffee. The ideal time range for an air roast is 8 to 12 minutes. A too-fast roast can underdevelop some of the coffee's flavors; an overly long roast will dull the flavor. Air roasts tend to develop the brightness of a coffee, drum roasts tend to develop the body more.

The larger machines like the the Behmor, HotTop or Gene Cafe are drum (i.e. conduction) machines and give a slower roast along the lines of the manual methods discussed above and commercial drum roasts. Roast times will be more in the range of 14 to 20 minutes. The comparison chart linked above has updated notes on size, cost, pros and cons.

Q: I want to roast outside - will this effect the roaster and the roast times?

A: The thing to keep in mind is that all of the small roasting machines have problems, no matter what the packaging or infomercial says! A key thing that impacts every machine first is your line voltage, which can vary 105v to 125v from house to house, and even on the same outlet depending on what else is running. (I know this doesn't perceptively affect your toaster -so why should it affect a roaster? I don't know why, I just know it does.) Secondly, the ambient temperature of the air will effect how hot the machine gets, so if you roast outdoors and it is much cooler or much hotter than room temperature, the roast will go much slower or faster. A very low ambient temperature will require the machine to work harder to reach roasting temperatures. The roast times as a result may be much longer than ideal.

Q: How long will a home roaster last?

On the issue of durability, all the small roasters, from my experience, last an average of two years. Longer if you use the machine less, roast lighter and clean the unit regularly; shorter if you use the machine heavily, roast very dark (the coffee oils tend to build up and clog the machines) and don't keep the screens clean. Some machines like the Behmor have been out less than two years so it is impossible to say exactly how long they will last. The HotTop can last longer because parts are available so you can replace a heating element or fan, for example, when that part goes bad.

I generally consider durability an issue in terms of the value you receive from the machine - both tangibly in terms of the cost of green coffee vs. roasted coffee, and intangibly in terms of how much you enjoy it, share coffee with friends, etc. If durability is paramount, use a cast iron skillet. If automation and control is key, then consider a machine. In the air roasters - a FreshRoast SR500 gives you more control over the roast than the FreshRoast SR300 and just about equals Iroast control. In the drum roasters, the Behmor, Gene Cafe and HotTop, in order, allow increasing levels of control and information about the roast time and temperature.

All the machines have design issues that can creep up and lead either to excessive maintenance on your part or inconsistency and early failure. I might hear more of the problems than anyone because I get the emails, so maybe I am over-representing the problems, but it is safe to say that none of the machines are 100% perfect. Choosing to use a home roasting appliance can make the process easier - but if it comes down to fiddling with a machine and struggling to get it to work, I think using a stovetop popper can be more rewarding.

More details on the pros and cons of each machine are detailed in the tip sheet for each roaster and the roaster comparison chart - and all of them, and I mean ALL OF THE MACHINES have pros and cons. Again, based on my experience, some roasting methods are a better fit for some folks than others.

Q: Do I need a more complicated (more expensive) machine?

A: Need is a funny term. I do stick my my comment above - that in choosing any roaster the main issues are how much coffee you generally drink and how much you want to spend. It is also good to know how you typically approach projects, i.e. if you like a more simple intuitive approach, or like a machine with more bells and whistles and things to play with.

The simplest machines - like the Fresh Roast SR300 which is a very basic unit with just time control and an on/off switch for heat - are fine and do a good job. The Fresh Roast can be a very fast, almost too fast a roast, which makes it harder to stop the roast at the right time. But it is affordable for most folks, a good entry level machine, and small enough for folks who don't need that much coffee. The Nesco is a bit larger and has a smoke reduction feature which is key for people who need to roast in an area with limited ventillation. Some first time roasters want to dive right in and get a big machine, like a HotTop, which always seems risky to me since the large batch size also means that if you misjudge a roast, you have wasted a lot of coffee. But spending money on a smaller machine first, and finding it is too small, can also be expensive.

The Behmor, Gene Cafe and HotTop allow you to control the temperature and time very. The HotTop has an optional programmable control board which gives you an incredible amount of control over the roast. More and more machines are allowing some programming of the roast since it is best to tailor the roast to the beans when possible - and it also allows you to compensate for low or high voltage, and low or high ambient temperature.

Q: Is there much smoke when roasting? I live in a small apartment, what roaster should I choose?

A: There is always smoke when roasting; less if you roast small batches to a light or medium roast, more with larger batches and/or a darker roast. If you have limited ventilation where you plan to roast, your options are somewhat limited. The Nesco Home Coffee Roaster (formerly called the Zach & Dani's) machine has the convenient feature of a smoke reducer, which is great but means that the roast is longer and slower since a faster roast overwhelms the converter. If you like dark roasts, you have to reduce the batch size and make other adjustments in order to use a Nesco roaster. The Behmor roaster too has smoke reduction and so has very little visible smoke unless you are roasting a large batch dark - but it might be too large a machine if you are the only coffee drinker in the house.

Q: How long does it take to roast coffee?

A: Air roasts ideally take 8 to 12 minutes and drum roasts about 14 to 20 minutes. Some hot air popcorn poppers can roast very fast - in three or four minutes.

Q: I’m afraid of screwing up and/or burning down my house.

A: Brave the smoke! Fire is a risk with any type of cooking - and with coffee there is a risk that the fine skin of the beans, the chaff, will ignite. If you have ever read the warnings that come on a toaster - the warnings on home roasters are the same. You never want to leave a roaster unattended, especially at the end of the roast. Many people roast outside because of the smoke and chaff - ambient temperatures permiting.

Q: Should everybody homeroast?

A: In my opinion, no. Homeroasting is fun and easy - you can try it out with an air popcorn popper or skillet to see if you like it. Homeroasting takes very little time or effort, but it needs to be something you are willing to/enjoy doing each week. So start small. We try to discourage relative newcomers from buying an expensive HotTop or such when they haven't even tried home roasting yet. You can get a few pounds of greens and just get a feel for it by using something you have around the house - like a hot air popcorn popper or a skillet. There is smoke when roasting, and a bit of mess as the chaff is loosened from the beans during roasting, so be prepared.

Q: I have a good local roaster near me, and buy fresh coffee each week. Will home roasting be better?

A: If you like the roasted coffee you get, that's great; support your local roaster. Many people don't have this option, or they simply don't like the style of roasts from a particular company.

Another point: we get people who say, "I love ______ (Peet's, Starbucks, etc.) coffee - how do I get that flavor with home roasting?" I say, "Go to the store and buy ______ (Peet's, Starbucks, etc.)." Really ... home roasting is essentially an "adventure in flavors" in which you find the coffees, the degree of roast, and the technique you like. If that already exists in ______ (Peet's, Starbucks, etc.), then why home roast? If you are not happy with what you can find, or want a bit more variety - that is a great reason to home roast.

Here are some useful links: