Are You familiar with roasting on an Ambex YM2? I'd like to hear your experience


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Jan 11, 2017
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Hi all

I've been using an Ambex YM2 since september 0f 2016. I've gone through about 6 whole bags plus a hundreds of pounds of broken down bags. Anyway, like any good roaster i'm always striving to learn more and do better. I roast for single origin, espresso, and cold brew. From City to French.

I used to put in 3 lbs 12 ounces per batch then I went down to 3.5lb batches. Charging temp was anywhere from 433-442F and with the gas control when I started out I was charging with full gas which on my roaster was 3 1/2" then I felt like my beans were scorching so I went down to 3", then to 2 1/2" and I've even done some roasts on 2"

When I start the roast at 2 1/2" I start with half air then at 6 minutes I open full air and go down to 2"

At the last 5 degrees of a roast i'll damper off with the gas closed

and this has been my latest roasting style

I keep trying different variables of air, gas and temp all the time

A friend of mine pointed out how all my coffees have a certain after taste. Like the last taste on the tongue and palate before going down. To me it seems as if its not completely developed and still has that underdeveloped aftertaste

In you experience what can I and should I be doing differently? How can I better developed my roasts without scorching or baking them?

Should I start with higher gas? Closed air? any advice or suggestions are welcome


Joe - what do you normal see as the first crack temp and drop temp? Just so we have a relative understanding of your roaster temps.

Your charge weight seems alright. To me - your charge temps are very high. I typically charge between 380-400 and my general philosophy is high heat to start and ramp down... airflow the reverse.. minimal to browning stage to wide open at FC.
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I start hearing the very first crackels at 390 then it usually ends by 415-420, my drop temps are 433 for Bali Blue Moon-450 for espresso blends

regarding airflow, I start with half and open full at first crack which is about 8 minutes

Also, when you say high heat you mean that your gas is open all the way at charge time just that you charge between 380-400? Because, since the charge temp goes down within seconds of when the beans hit the drum so how does that even affect the roast?

And just so we're on the same page, when I say that my charge temp is around 440F I'm talking about the bean probe temp which is what Ive always been going by
Charge temp to me is the temperature of the "roaster" prior to charging the drum with green coffee. I use Bean Temp as my measure of the roaster / I.E. - charge temp. For reference most of my coffee hit FC when my machine reads about 385, and just a touch into second crack at 432 - so are machines are fairly close in temp readings If your initial charge temp is really around 435 start by lowering that down to eliminate scorching.

Regarding the heat.. I run a USCR 12K... so hard to tell you how to set your gas. Once my machine has stabilized to my desired charge temp I set the gas to the lowest setting possible. Drop my green... wait 30 seconds then apply heat. I find the drum has enough heat on initial charge gas is not needed. I then apply heat as needed to hit my target time for 'Dry time". I don't pay much attention to the turning point ..
Razzo Coffee has an Ambex YM2. He has developed a nice profile. He is on this site occasionally but send him a PM
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Thanks Musicphan

I will try charging at 400 and see what happens. How long are your roasts generally, how much heat do you apply at the beginning? How do I now prevent too long of a roast so that I shouldnt bake my beans?

thanks I'll reach out to him
My roast are generally around 12 minutes... 5-5:30 minutes to dry, at 10 min mark to FC, drop at 12 (approx 20% development). That's where i start and I adjust to taste.
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When you say adjust to taste can you slightly elaborate on that? Because I hear that alot

I understand the concept but not so experienced in actually doing it
When you say adjust to taste can you slightly elaborate on that? Because I hear that alot

I understand the concept but not so experienced in actually doing it

Well ... that's where trial and error and years of roasting come into play. I highly recommend Rob's book:

Products - Modulating The Flavor Profile of Coffee by Rob Hoos ? Nossa Familia Coffee

And there is Willam Boot video talking about acidity.. basically the faster your ROR the more acidic.. I can't seem to find the video right now.
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So Iv'e been trying my roasts with a lower charge temp, from 440 i went down to 400f and then adding gas etc. The results were absolutely amazing. I have never roasted a more flavorful Nicaragua or Sumatra, so far, with sweet notes and body.

However, at the very last taste, the taste that lingers on your tongue after you swallow, it leaves a non pleasant nasty acidic like feel. The non pleasant acidity. As if theres like an ingredient in the beans that leave you with a nasty aftertaste.

What can I and what should I be doing about this?

When I charge at 400 degrees I add 2 1/2" of gas with closed air. Then I open the air half way at about 4 minutes, and full air at first crack which now comes a drop later in my roast then it used to when I charged at 440 or so. I also lower the gas a bit to about 2" if I see that after first crack the ror is moving to quick

Full gas would be 3 1/2". Should I be giving full gas after charge time? What about air?

Your suggestion to charge at a lower temp was great advice. Any other advice would be greatly appreciated