Welcome to Ask the Alchemist 200.  I would not have done it without all your questions. Thank you.

For this special number, I took the opportunity to start delving into probably the one part of chocolate that excites me the most. 


I LOVE ROASTING.  The sights, the sounds, the smells.  It is just a sensory smorgasbord and you can do SO MUCH with it.

I want to share that.  I want you as excited by it as I am. 

Oh, the question may not at first seem like it relates, but it does.  Have I ever lead you wrong?

Let's go.

Level: Apprentice

Reading Time: 5 minutes

I’ve been roasting in my convection oven at 250 F but I can’t tell when the beans are done.  How do I tell?

In one short sentence you have brought to a point the reason I very much dislike oven roasting.  It is nearly a black box and it is really hard to know what is going on inside temperature wise.  It doesn't tell me or you anything helpful to know that the oven is 250 F. That means I can’t help in any constructive way. I don’t know the power of your oven, how much you roasted or what temperature you pulled them out at.

Really the only thing I can tell you is to roast until you get some chocolate aromas.  Then make the chocolate and see if you like it.  The depending on the taste you should roast longer or shorter.

If on the other hand you had told me what the surface temperature of your beans were at different times I might have been able to offer some advice.  What you would have given me would have been something called a Roasting Profile and in 17 years of roasting (17 coffee, 14 cocoa) it is the ONLY reliable way I have found to have a meaningful conversation about roasting.

And I have really steered away from it for too long in fears of overwhelming people.  But in all honesty I failed to give credit where credit is due.  There is no reason everyone reading this can’t understand roasting profiles if they want to.

To that end, this is a graph of a roasting profile.

What you should notice first off is what is lacking. 

·         There is no mention of oven or roaster temperature.

·         There is no mention of how much I roasted.

The only thing given is the surface temperature of the beans because it is what can be measured.

The beauty of a roasting profile is those other things don’t matter.  The shape of that profile, or more specifically, the shape of 4 parts of that curve really determine how the roast will effect the flavor of your cocoa beans and thus your chocolate.  Just so you can hear them, the 4 parts as I am defining them and how they relate to temperature  are:

1.       Drying phase (ambient to 212 F)

2.       Development phase (212 – 232 F)

3.       Finishing phase (232 – EOR)

4.       End of Roast (EOR)

The EOR is just the point where you stop the roast.

It looks like this.

If you can’t construct or convey the information needed for me or someone else to construct a graph like this then you don’t have a Roasting Profile.  You may have a roasting method and it may well work for you, but it isn’t a sharable roasting profile.  250 F for 45 minutes isn’t a profile because I can’t construct a Profile curve from it.  It is as simple as that.

And that right there is really the purpose of a Profile.  To share from person to person, roaster to roaster or just batch to batch.  It is so you have a baseline that you can adjust from in a meaningful way.  So that is what we are going to start talking about a lot from now on.

Coffee roasters have dealt in profiles for YEARS.  Cocoa roasting is frankly behind the times and it is time to catch up.  So let’s take one piece and go from there.  With that in mind I want you to ask yourself a question.  How many coffee roasters use a convection oven?  I would hazard to say a big fat zero.  It just isn't a good way to roast from the lenses of predictability, consistency and control....everything you want in a roast.. 

Drum roasters on the other hand....yep!

Since you asked about when the beans are done, I’m going to share how that point can affect the flavor of your chocolate.  That point is the End of Roast (EOR).  How you get to that point is of course important, but it can have a profound effect on the flavor.

I roasted 35 lbs of Piura Blanco in my Royal, and sampled a kilogram at 7 different temperatures, making chocolate with each sample.  In scientific fashion, each batch was identical in every way.  75% cocoa, 4% cocoa butter, 20% sugar.  Sugar was added at the beginning (not that I found it mattered, more on that in another article) and the chocolate refined for 48 hours, then tempered with 1% silk.

Here are my raw EOR Roast tasting notes.  Piura Blanco.

232 F. Sharp and sour aroma. 2.0 Choc, Astringency 4, fruit 2.  Light bile like burn.

245 Bright and low sour aroma.  Not very complex.  Pith like astringency 3.5.  Moderate to low chocolate 2.5

252 Lovely passion fruit nose.  Bright dynamic fruit flavor.  Passion fruit and apple blossom. Fruit 4.  Sweet. 3.5.  Chocolate 3.5.  No notable astringency.

255 Nice aroma.  Compared to 252 lower.  Chocolate 3.75 Bitterness is up but in a good balanced way.  Lower fruit notes but could be perception due to more chocolate?

260 Aroma of soft dried fruits.  Chocolate remains high @ 3.5.  Jammy malic acid acidity.  No offensive astringency.  Tannins are up and contribute body

265 Dried fruit aroma of raisin.  Chocolate has dropped to 3.0 although still solid.  Acidity has lowered and is flattening out.  Deeper, darker dried fruit notes are dominating.

270.  Dark fruit notes less.  Sharp metallic taste of some dried fruits and caramelized sugar as in crème brulle.  Deep chocolate notes.  2.9.  More noticeable due to a lowering of other flavor components.

Look at how the spider graphs change.

I’m not going to tell you what I think about this.  I want YOU to start making some conclusions.  Try and forget what you think you know and go by the data in front of you. 

What patterns do you see?  What surprises you?  What doesn’t seem to make sense? 

Let’s have a conversation about this.  Please, ask me questions.

In the coming weeks and months I’ll start picking apart the other phases as well.

Ball is in your court.