I'm just starting out with roasting. I do not own an actual roaster however, but I have a decent hot air oven. Yesterday I did my first batch in the oven. Unfortunately, the both the flavor/aroma and the good smell from the roasted beans is lacking quite a bit. I figured maybe it just needed to rest, but after 1 day, it's still quite flat aroma-wise. I use the beans in espresso.

Anyhow, then I started reading up a bit.. a lot of people were talking about baked coffee beans. The descriptions matched my experience quite well - a flat taste. I saw a lot of articles talking about roasting profiles, which I do not have the equipment to control anyway.

Here's what I did, step by step (note to self is to time more accurately ):
- For my first batch, I pre-heated the oven to 160C (320F).
- Then, I spread the beans (200 grams) on a baking sheet (no overlap), and set the oven temperature to 220C (428F). The temperature were reached after probably about 3-4 min. After about 9-10 minutes I heard the first crack start. At about 12 minutes I took the beans out. Could be that was a bit early.
- I then cooled the beans by bouncing them around a bit in a kitchen sieve. It did take a while to cool them thoroughly.
- Finally I put the beans on a glass with a loose lid to allow the gas to escape.

It's my first try, and although the result was not great, I'm eager to improve. Which is why I'm here with a bunch of questions before I try again!
- Is my problem related to temperature? Should I use a higher temperature? Do I need to gradually increase temperature (which I can do in 5C increments on my oven)? Or is the issue something else?
- Could the problem be that I stopped the roast too early? There definitely were smoke when I took them out, but the beans are definitely not dark roasted.
- Is roasting in an oven a dead end? Is using a skillet better, or should I just be getting a popcorn popper? Before I know if roasting is something I want to do moving forward, I'm reluctant to invest in a full-blown roaster for now.
- How soon after roasting should I actually smell the good smells from coffee? I'm sure you know what smells I'm talking about... My first batch had almost no smell after getting out of the oven. After being in a closed lid for a few hours I have started getting some good smell.
- Am I just too impatient, so that it's just a matter of letting the beans rest for a few days? Going from almost no aroma to at least some?

Thanks!

Heat gun dog bowl is popular starting place

Thanks for the tip - I don't have a heat gun though.

The intention of my post were first of all to learn a bit about what I did wrong/what I can do differently.

hal9001 wrote:The intention of my post were first of all to learn a bit about what I did wrong/what I can do differently.

You used an oven. If that was easy to master, you would see many of us here using that method.

A heat gun is cheap in a hardware store. You would also want a long spoon to stir the greens. Some people start with a skillet on the stove. You mention a popcorn popper. That works too. Cooling the beans is faster if you rig up a metal screen inserted into a paint bucket with a hole in it so a fan underneath can pull air through the beans.

My first workable roaster was a modified bread machine with a heat gun. This is also called a Corretto roaster. I inserted a thermocouple in the bread pan to measure bean temperature and another in the top grate to measure environmental temperature. I made a bean cooler like I just described. This let me use Artisan software to control and profile a roast. There are other inexpensive ways like this to assemble a roaster you can control for good results.

Right - the reason I figured the oven was a good idea was that it would be easy to create a repeatable consistent result... obviously that doens't help if it's consistently bad results

I guess I got an answer to most of the questions - that ovens are not optimal for this at all and that I better move on to other methods. And thanks for the tips about the heat gun + bread machine. That looks interesting - I might look into that. It would be awesome to have a bit more control - and I do like tinkering.

The last question on my mind then is the fourth on my original list - when I'm experimenting with roasting, should I have a "proper coffee aroma smell" right after roasting, or does this need time to develop? In other words, how long would I need to wait before I know if I can use the smell to at least get a hint of whether a batch was more successful or not?

For the record - today I plan to test with a skillet. Mostly because it's what I have at home right now. I'll let you know how it goes!

hal9001 wrote: The last question on my mind then is the fourth on my original list - when I'm experimenting with roasting, should I have a "proper coffee aroma smell" right after roasting, or does this need time to develop? In other words, how long would I need to wait before I know if I can use the smell to at least get a hint of whether a batch was more successful or not?

I roasted some coffee today. It had "proper coffee aroma smell" during toward the end of the roast and has had a nice aroma since. I don't really recall if this is always the case (I think it is.)

FTR I think it is easier to get better results with a heat gun than oven or skillet--at least in my past experience. Heat guns are pretty cheap.

Thanks for the answer!

I did try the skillet method just now. Although I still have ways to go, I did get a decent smell right after the roasting were done. It did turn out a bit on the darker side than I like - but I've made notes so I'll experiment a bit. Also you all have convinced me to purchase a heat gun next week... taking it to the next level

I guess coffee roasting is another one of those rabbit holes...

I first started roasting with a heat gun and dog bowl. See thread: I cannot shake the desire to roast

What I learned back then is the heat gun has very high temperature air. And if it is blasted directly onto the beans, then they get scourged a bit. While this is somewhat controllable, you will be limited due to relatively low airflow and lack of heat being transferred if you drop the heat gun temperature (by getting a variable heat model).

To overcome this, it is best to contain as much heat as possible and agitate the beans as much as possible. This means the beans should be inside a closed insulated container with heated air flowing in and smoke/chaff blowing out. Often folks retrofit bread machines for doing this. The bread machine agitates the beans, and heat gun provides heated air. The box is insulated to help hold in and surround the beans with heat to maximize heat transfer without as high of temperatures.

Lastly, consistency is king. When you find that optimal heat source, setting and airflow for the perfect tasting coffee, you will want to duplicate it. Or duplicate with a minor change to make it even better. This is only possible with a consistent roaster.

Please don't let this information discourage you from roasting in a pan or dog bowl with a heat gun. Part of learning what is right is learning what is bad and what roast defect tastes like. Later, when you start getting good at roasting and you will have the experience of tasting the slightest defect. And you likely will be surprised when you taste these defects in "good" commercial coffee. You will then realize the bar has been raised to the next level.

Home roasting is a very worthy hole to discover. I look back at where I was at the beginning and realize just how much I have learned and witnessed how many different flavors coffee has to offer.

Concurring with above don't use the oven:
Minimum starting point: Either dog bowl/heat gun or modified hot air popcorn popper.
If you google there's a ton of info on both & on roasting as well.
There are some basic roasting books.

Sweet Maria's website has some good info on roasting as well.