I never thought about roasting my own coffee until recently.
Two circumstances came together to result in a happy little experiment that became a more regular habit.
The first was economics, more specifically the need to save some money! Nothing like having your income curtailed suddenly to get the creative juices going. The second was a serious look at the data suggesting that coffee was one of those foods that you should absolutely invest in an organic source.
I had heard but never looked seriously at the information that suggested that coffee plants and coffee beans are subjected to all kinds of pesticides and toxins that accumulate in the final product. And you must remember we pour boiling or near boiling water over the grinds to “extract the juice”- a sure fire way to make sure everything in that plant winds up in your cup!!!
And while we are on the topic of toxins, be sure and avoid plastics around your brewing process. For example: I used to use a “gold” coffee filter until I realized the frame was plastic. And if you use K cups anywhere well good luck to you. Plastics have anti-androgenic and pro estrogenic compounds that can cause major problems with female fertility, male sperm counts and a scary association with DNA damage and cancer! If you are going to use the process below finish it off with a non plastic containing brewing system!
So, knowing that I have no control over those chemicals, and understanding that like fish oil, coffee was something that I had been putting in my body for a long time and would likely continue that habit on occasion I decided to take control.
I buy organic green beans and roast them myself.
Now for the disclaimer: I am not a coffee expert, I just like a good cup from time to time! I am not a roasting expert either. As a matter of fact, serious amateurs and professionals would certainly scoff at the advice I am about to give you noting its flaws and how you cannot brew a perfect cup without at least a thousand of dollars of equipment.
Again, a reality check at least for you and me. If you can do it for say 20 bucks in equipment versus a thousand are you personally going to be able to tell the difference? I know I can’t so I’ll save the $980 dollars!
Before I get into the actual technique, its worth at least a historical look at coffee and cancer. Back in the dark ages when I was a young Internist coffee was implicated in various and sundry cancers including pancreatic cancer. Over the years it has slowly but surely beaten the wrap. Currently it’s totally off the hook and even noted as having a decreased association with some cancers.
A simple caveat is “everything in moderation” and so it is with coffee.
Ok let’s get to the basics.
I have an old oven that I haven’t used a lot. That means it is not exactly accurate in temperature so your first device purchase is an in-oven thermometer just to make sure you are not all over the place with temperature.
Next seek out some cookie sheets to put your beans on. I use the type that has an “air layer” in between. In other words, it’s not just a flat sheet but one with an air space in between the top and bottom. Theoretically at least this should create a more even temperature.
It helps if your oven has an internal fan that circulates or vents air. Many do and if yours does turn that switch to “ON” and leave it there for the duration of your coffee roasting.
You are going to use a broil setting on your oven and set the temperature for around 400 degrees F.
Distribute your organic green coffee beans evenly over the sheet leaving a little space between them if possible and don’t get too close to the edges of the sheet as it will make it hard to coral the beans when they are done!
Your sheet and beans should be placed into the oven about 6 inches from the heating elements which on most ovens is the top rack setting.
Once the oven is heated set a timer for 7 minutes and slide in your sheet with the beans on it carefully so you don’t wind up with an oven full of beans!
I would recommend keeping a really close eye on things the first couple of times you do this because of variations in oven temperatures and such. Also in terms of broiling I do not keep the oven door open for this process the way you might for a steak. I just shut it and check on it frequently opening the door when needed to assess the color of the beans.
It is possible to incinerate coffee beans and they do catch fire if you crank the oven temp up too high. Ask me how I know!
At or around 7 minutes you can open the oven door and you should see the beans are getting a nice brown color on top. Carefully slide the broiling rack with the sheet on it out of the oven taking care not to touch anything with unprotected skin! They make really nice heat proof gloves these days for a couple bucks that make handling stuff in the oven much easier than the old-school mitts we used to use in grandma’s kitchen! But if your not ham fisted, those work too and will help you move the beans and expose the unroasted parts if the technique I describe below is not working well for you.
Once you have clear access to the beans on the sheets, you need to gently rake them with a spaghetti fork or some other rake like device that will expose the unroasted parts of the beans.
This is one of those things that requires a light touch and one pass only. If you start raking the beans back and forth over and over again you wind up pretty much where you started. So just use the fork to expose them one pass over each part of the sheet and slide them back into the oven. If this process takes more than one minute you are spending too much time raking and creating more work for yourself.
The key is to allow as much of the bean as possible to be exposed to air during at least part of your roast. The most likely difference between you and me doing this in our ovens and buying roaster that costs a ton of money is air circulation.
I recommend decreasing your oven temp by about 50 degrees while you have the door open or the oven will try to maintain the original temperature by heating up a lot. This will result in you over heating the beans and scrambling to get a smoking mess out of your oven! When you put the beans back in turn the temp back up to 400F.
You may also start to hear what sounds like popcorn popping. If you do start to hear that before 7 minutes, then rake the beans as soon as you start to hear that noise.
After your first “rake” make sure you are close by your oven because you are going to start hearing a lot more popping. That is exactly what you want. Some people even recommend you gauge the roast by the popping like you would popcorn. I have not found that to be reliable.
Repeat the raking process a few more times interrupting the popping as needed.
Now again since this process is not perfect, you are going to notice some color differences in the beans. You may get a few that look like espresso e.g. very dark and oily in color. You can theoretically and in fact get them to all look like that if you want by keeping them in long enough at the higher edge of their temperature tolerance.
Personally, and for reasons of decreasing the potentially harmful caramelization process I shoot for most beans being in the medium/deep brown color or what is called a “lighter roast”.
Play around a little and find the color you like- it definitely affects the taste in a major way and you may like the darker roast or a lighter one. Frankly, so far, I’ve found the degree of roasting has more to do with the flavor of the finished product than the actual bean type. You will most surely find a favorite bean or two though as you do this. I particularly like Mexican and Columbian coffee beans, and they are very different in character and flavor.
As with most things starting with a good quality bean is essential. I have found several green organic coffee bean suppliers on eBay that are great to deal with and have extensive stock and as many different coffee bean origins as you could imagine.
When the beans are done to a color you like and reasonably uniform in that color (the one thing you don’t want is green unroasted or poorly roasted beans!) remove the sheet and let it cool in a safe place.
In about 20 minutes you can move the beans into the container of your choice.
Now here comes the tricky part. I decided to funnel my beans into a 3 quart Pyrex glass container so I could pour them into the grinder or storage bin without having them fly all over my kitchen. Again, ask me how I know this can happen!
The simplest thing I found to help funnel the beans into a container was a 5 dollar “French fry” funnel- one of those things fry vendors use to put the fries into paper cones or whatever they serve them to you in.
I got mine on Amazon but again I suspect you could find them elsewhere. Stick the fry funnel into your solid container- again I use a Pyrex glass cup- and carefully guide the cooled beans in using your hand to concentrate them into the center of the cookie sheet as you go.
Once in the container you can store them or grind them. Now they will have some “chaff” or chafe associated with them. This is the outer skin of the bean that comes off with a “pop” that you heard in the oven. Purists will insist you remove this and may have all kinds of complex ways but in all honestly I cannot perceive it alters the taste of the final product much at all.
Speaking of final product, you will most likely never get your coffee any other way once you start doing it this way.
It may seem complex but it is not hard at all. Frankly it’s much harder to describe than it is to do and the better you are in the kitchen the easier time you’ll have of it. Either way a little experience and you’ll be a pro.
Roasting beans is not like baking! It’s not nearly so delicate a process and its ok to have temperature drops and swings so you can slow down the process and control it better. You will most likely find though that the temperature setting is fairly narrow. Too low and you will be looking at green beans for a long time. Too high and you will be scrambling to get the beans out of the oven and open windows in your kitchen to let out the smoke. That said, after a few trials you’ll become a pro and be able to have the best cup of coffee you’ve even had any time you want it.
Normally, I load two sheets at a time although I only put one in the oven at any given time. Two sheets “full” of beans will give you about a half pound of ground coffee.
Have fun with this and enjoy!
The one and only original Dr Dave!
PS One final set of tips. Have your vacuum cleaner handy and have the wand attachment on to help clean up afterward. Bean chaff and other residual stuff like the inevitable bean that just doesn’t want to stay on the sheet or in the oven will occasionally happen so it helps to be prepared. Remember you are dealing with hot items so be careful around kids and let everything cool before you move it to storage or clean up afterward. Remember to turn your oven OFF!