Hay/grass aroma

[Mo Helu]

Hi guys/gals

Newbie here so please go easy on me

Coming from an air/popcorn popper with superficial knowledge of the whole process

I recently got the Nano and with high hopes I thought I should start with the most basic approach. I.e. load the beans, choose a profile and let it do its thing. This how I like to learn, basics first.

I like (light to medium/medium) roasts for espresso - mostly milk based drinks

So, I loaded the measuring cup to it's brim (<120gm), into the roasting chamber they go.
Multiple attempts and chose different profiles for two different kinds of beans (Indonesian and Nicaraguan). I also used the KL Classic profile for a blend of green Ethiopian beans (-- as I said, go easy on me :p).

The problem, with ALL attempts, I am getting hay/grass aroma. This has persisted even after letting them rest for few days. It is borderline unpleasant and I would not have brewed them but I ran out of my old batch. I used to achieve very reasonable uniform roast and hint of pleasant acidity (with the Ethiopian blend) even mixed with milk. Now, it is un-inspiring and just coffee, if you know what I mean.

I looked online and apparently it is to do with the beans being baked as opposed to being roasted. Or lack of development. Forgive my ignorance, does it mean that the beans are not heating quickly enough?. Yet, the FC for most attempts comes around 5 min or thereabout. In the ballpark of my old hot air roaster.

Keen for some feedback please.
I am sure that the Nano can do better than this and it is an operator (me) issue.

Cheers
Mo

[nrdlnd]

Hi Mo Helo,

I'm sorry no one else have answered your post. I saw it today. There is something strange with many of the logs that they don't follow the profile. The only log I think looks rather ok is No 8 (it doesn't look baked). The other roasts don't look typically baked either. I wonder about your beans? Are they old? The beans are most often the reason for bad taste. The first thing I would have done is to try a smaller batch size such as 100g as the movement of the beans may have been inferior. It's not possible to determine how developed your roasts are as you haven't marked 1st crack. I use to do that when there are a couple of cracks in succession. For me 1st crack usually comes later than 5 minutes (7-10). Edit:Wrong from me! 1st crack can come after about 5 min. I'm usually focused on the temperature and FC usually comes after 205 deg C often up to 210 deg C. You can read in the manual how to record FC. To be able to more accurately record FC I'm using a sound recording app on my mobile to help me register in the log.
I see that you mainly drink espresso with milk. Have you tried filter coffee or cupping so it isn't your espresso making that fails? And a tip: In the log file you can under "about" write notes about what bean you have roasted and the taste. Are there any roasting faults such as tipping or burning? Initial weight and end weight? This can be valuable when you analyze your roasts.
If a smaller batch size doesn't help and your beans are fresh and of good quality I think you should contact support directly (Chris Hilder). It could be something wrong with your calibration. The environment (climate, temperature) can also affect the roasting process.

I wish you good luck and please report back how it goes!

[Mo Helu]

It is so nice of you to reply to my post. I appreciate your time, input and valuable troubleshooting ideas.
I have been in contact with Wayne and he's kind enough to offer to help and we are arranging for this Friday.
All points you've raised can certainly be a possibility and I'll attempt to address/tweak accordingly.
I'll keep you posted.

Many thanks again!