Roasting - Convection Oven

[mark]

Nationally, our chocolate is regarded as the best available domestic product. However, I am still not satisfied. Since 2020 we've used a convection oven for the roast. I don't think the beans are roasting evenly because for one thing the oven doesn't heat evenly. It was built in our country, Honduras, and therefore affordable, but I think the fan is inadequate, and the heating element too close to the product. The other is that I just don't know that you can evenly roast with a convection oven, even with a good brand.

We are looking for a roaster that was built only for roasting seeds, beans, nuts etc. We have some leads on some good ones that won't break the bank.

So, let's say that currently the seeds vary in final roasting temperature by +/- 20F, and a real roaster could shore that up to +/- 5F. Will that improve our quality greatly?

Specifically, I am hoping for a more refined, less bitter flavor. Again, our brand is good, but I think it could be better. I've read your article about roasting temperatures, and it looks like you concluded that 265F is the best roast, at least for the beans you use. In Honduras, it seems that everyone claims to grow Trinitario; our main supplier is reputable.

Kind regards,
Mark C.

PS: I got my start in chocolate back in 2014, by reading your articles, MANY, THANKS!

[Ben]

Hi Mark! I've moved this thread from the Ask the Alchemist forum to the Roasting forum. Alchemist John doesn't really ever come onto the forums anymore. If you'd like him to weigh in, you'll need to email him directly or submit a question on his Ask the Alchemist page: chocolatealchemy.com/ask-the-alchemist

Personally, I am a big fan of a drum roaster because they give a much more consistent roast than a convection oven--even a good convection oven. All convection ovens have hotter and cooler spots, so you're always going to get some variation. While a consistent roast doesn't mean a good roast, it does give you more control over trying to compensate for the shortcomings of an oven. From your description of your oven it does seem like it has some specific shortcomings that could lead to a less than ideal roast.

Where did you see that Alchemist John concluded that 265F was the best roast? From what I've read from him, I don't think he would say that one specific end of roast temperature (EOR) is the 'best' roast. Different roasts will bring out the best flavors in different beans, so while 265F may be a good EOR for one bean, it is probably a terrible EOR for others. For me, I currently work with five different origins and don't roast any of them as high as 265F.

Also, as John discusses in his series on roasting (starting around Ask the Alchemist 200 IIRC), the EOR is only one data point--how you get to the EOR is just as important for developing flavor. I'd start with that series of posts if you're looking to improve your roast.

[Ben]

Regarding roaster recommendations, I'd look at a coffee roaster that has controls for power, drum speed, and airflow. I use a small roaster from Buckeye Coffee Roasters here the US, but it's just a rebranded chinese roaster that is probably available from Alibaba.

[mark]

Thank you for your quick response.

Now I can't find the 265F roasting recommendation, but I just looked it up last month. It had a graph with 4+ roasting temperatures, and the different scales for multiple quality points (including chocolatey, acidity etc).

I've been looking at the Alibaba roasters. The bottom of the price scale don't even have thermometers. I'm assuming we'd want at least that. I don't know about airflow, but they do have a rotating (drum?).

The thing that's lacking from these low end roasters is the cooling fan once the roast is done. Right now we just take the full sized cookie sheets out of the oven, put them on a rack with wheels, and push them to a breezy window. Without a cooling fan I'm guessing you wouldn't want to roast the beans as much, but not by how much.

Kind regards,
Mark C.





I found the "video" because I had downloaded it a month ago, still don't remember the source. At second glance, somewhere between 250 and 265 looks like the best roast?

[Ben]

You'd definitely want at least a thermocouple in the beans and one that measures the air temp, so if the low end ones don't have that, I'd consider that a deal breaker. A cooling tray is very helpful, too.

I'm not sure what that video is either, but I don't think it says anything about a 'best' roast. My guess is that it's showing different flavor profiles for one specific bean roasted at different levels. It's not making any claims for all cacao. Every cacao needs to be roasted differently to bring out their best flavors--there's no best roast for all cacao.