Roasted a batch of Guatemalan, but the result was not good. The target roast degree was to be a full city, but achieved about a Vienna. The interesting results were the roast was not evenly roasted. This is the first time, I've experienced this issue. Some beans were darker and lighter than others.

Below are two photos for reference.

The first photo provides the gradient of the roast.


Another photo featured is one of the beans, I'm suspecting as bad. To show the internal color, I've cracked it.

Note: The other beans seemed to roast fine based on the color.

Question: Is is possible those beans are defects or could it be the beans are expired?

Comments: I went ahead and removed the suspect beans. After pulling a few shots, the appearance of the color and espresso looked very great, but the taste had some sourness notes.

Thanks!

I've seen I-roasts with poorly calibrated thermostats that read too low. They do roasts that are too hot, too fast, and with not enough time in the high fan setting. The result is a very uneven roast. Properly calibrated, roasts should run at 7 to 10 minutes from light to dark.

Is that what's happening here? Or does the roaster work well for other beans?

A majority of all my roasts from this roaster has provided fairly consistent roast results. I've roasted probably about 10 batches to date, and this particular batch turned out undesired results twice. I roasted this batch a few days ago and tried it again today and got the same result.

My roast times are generally completed anywhere from 7.5 - 8.25 mins.

Very rubbishy beans then. When roasted into the 2nd crack, even 3rd rate beans should look pretty.

Ok. Thanks!

another_jim wrote:Very rubbishy beans then. When roasted into the 2nd crack, even 3rd rate beans should look pretty.

Yes I agree
Probably picked green or not quite ripe off the tree and mixed with ripe ones

KK