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Is there a general discussion on the site about the effects of conching/grinding vs. roasting on bitterness and astringency?   I've been reluctant to grind for a long time because I thought most volatiles were driven off in first 12 hrs and afterwards I might drive off interesting flavors but I'm dealing with some bitterness I want to get rid of and I'm not sure if this is really about roasting or grind time. I've read much debate online about whether conching actually does anything in modern chocolate making.

Up to this point I have not talked about bitterness and astringency as related to refining and conching.  Most of my discussion has focused on roasting.  Check out ATA (ask the alchemist) 203 and 205. 

Cocoa beans have a natural bitterness and natural astringency in most cases. It is part and parcel of what makes it so interesting.  Clearly you don’t want too much and it seems many people go out of their way to pick beans that are super low in both thinking of those characteristics as a defect.    My take has it is always about balance.

I have had raw cocoa beans directly form pod.  Their levels of bitterness and astringency were all over the board and there seems to be some token correlation between the broad categories of Criollo, Trinatario and Forastero and increasing levels…but there are plenty of exceptions.  I had a general hybrid out of Hawaii at one point that stands out as one of the worst tasting experiences of my adult life.  It was so astringent that it rivaled a mouthful of alum and I was spitting it out without conscious thought.  I’ve also had fresh Amelonado (one of the varieties of Forastero) that had only a hint of astringency and bitterness.  My point is that you should be careful not to generalize and be aware of the trends but also the exceptions.

That is the perfect segue to talking about volatiles being driven off.  You have taken a very general principle and applied it so broadly that it sounds like you are frozen with indecision how to even refine without harming the chocolate.  What is generally recognized is that many of the volatile ACIDS are driven off during the first few hours of grinding and refining.  If some other compound is so very volatile that it too is going to be driven off then there is not a damn thing you can do about it and you need to stop worrying about it.

Somewhere the mentality has arisen that chocolate is this hyper delicate creature whose flavors and aromas must be handled like nitroglycerin least they escape and ruin your chocolate.  Low, long delicate roasting.  Cold grinding.  Cold pressing.  Short, cool refining. 

What seems to be missing from those conversations is the fact that what you have come to love about chocolate is from chocolate that had none of those cares taken.  In an attempt not to over roast, over heat, over refine and over conche the pendulum is swinging hard the other direction to thinking the only way to make good chocolate is to minimize all those parameters.  It is about avoiding the extremes.  It is about balance.

Here is how I look at this from a practical view.  Over the years I have come to think of flavor profiles in the terms of colors and pigments and it is up to you to make the most pleasing picture you can.  That is your responsibility. A painter knows that the most dynamic highlights have to be contrasted against darkness and shadow.  They are not worried about the painting being ‘too dark’ (read bitter or astringent).  They apply color. They mix colors to make new colors.  The overlay colors to add depth.  They are NOT portrait restorers.  They are not trying to clean up a portrait yellowed by age, taking delicate care not to hurt the underlying picture they know is there.  Restorers have to be delicate but painters less so.

This isn’t what we are doing when we make chocolate.

It isn’t about treating the cocoa gently trying to unearth what you hope is underneath with no control over what is there.

I want you to go take two and half minutes and watch this time lapse of someone oil painting.

This is how I see chocolate making. It is creation. 

It is my firm belief that you are not trying to uncover what is there.  It is about taking each step, using the palette of colors you have on hand, doing your best not to introduce defects but not being afraid to be bold.  At any point it is possible to ruin the painting by over application of a given pigment (over fermenting, over roasting, over refining) but you still need to boldly ferment, roast and refine!

Now, by the time you get your beans you are not working with a blank slate.  The basic sketch is laid down, and the first under painting is there too.  It is your job to work with it now.  Develop the highlights, mix the colors, and  blend them together.

During the roast you are mixing the colors.  You are creating flavors that did not previously exist.  The heat allows chemical reactions between compounds that were previously created during fermentation.  Some of these reactions reduce astringency, an important reason to roast full.  If you don’t add enough heat the right way you can fail to get the deep color/flavor you are looking for.  Of course you can introduce too much of one pigment by over roasting.  But it is more subtle than that.  There are more nuances than that. 

For one painting, you can get away with adding a dark pigment to red pigment.  Yellows and pastels can’t handle as much dark.  Blue and Red can.  In roasting this means you can roast more aggressively if you have a lot of potential chocolate and fruit flavors.  If your chocolate is very light on chocolate and fruit (pastel) then you do indeed need to keep the roasting less aggressive so don’t cover what chocolate and/or fruit flavors are there.

This is the kind of thing I see when I think of what lightly flavored chocolates taste like when roasted in that long and low and delicate fashion.


Certainly not bad.  Completely inoffensive.  And in a world where there is bad chocolate, inoffensive can actually be quite notable. But in my opinion it is leaving so much potential unrealized.  With a proper roasting you can develop flavors and make the whole more vibrant, yet still delicate.


Of course, you can ruin that too by roasting too aggressively and causing defects

Too aggressive.jpg

Roasting too hard (I am referring to ramp rates, not end temperatures) can lead to bitter defects.  That wash of red in the above case ruined the picture/chocolate.  But say we have a full flavored one bursting with chocolate and fruit.


This chocolate treated the same way (wash of red added) and with potential defects added, you hardly notice the difference.  In point of fact, I added twice as much red (roasting defect) to this photo.

Blue highlight.jpg

The other flavors/colors can balance it and it is a far cry from ruined.  It is merely different.

In much the same way you lay down the sketch in a painting, then the foundation, the highlights and then details, as you progress you are building upon what came before and consequently it actually becomes harder to truly ruin the whole. 

Chocolate is no different.  If the beans are quality and the fermentation is good, you need only roast well.  After that, refining and conching can become almost afterthoughts.  Roasting is layering in your details - important for the final product but almost useless if you are not starting with a good base.  And once those details are in, refining is just blending the edges and smoothing out the rough spots. 

All that is my way of saying that each step is refinement of the whole and you can mess up but it gets progressively harder to do it accidentally.   But it isn't impossible.

bad finishing.jpg

The corollary to that is that you should not be trying to fix foundation issues (it’s too bitter or astringent) during the final phase (refining).  It is the wrong tool for the job.

Going back to your initial question, you should not be trying to fix a bitterness or astringency issue in the refining phase.  At that point the die is cast.  It is too bitter and/or astringent because of one or more of the previous steps.

  1. The bean itself is bitter.  The only solution is to use another bean.
  2. The beans were under fermented.  Again, don’t use that bean.
  3. The beans were under roasted or treated too delicately.  By doing so other flavors were not developed that would cover/mask/complement the bitterness
  4. The beans were roasted too aggressively and basically singed. 

Somewhere it has come to be thought that refining and/or conching reduces bitterness or astringency but I cannot say I have ever noticed that trend.  What I have seen is that chocolate can taste better under certain circumstances as the chocolate continues to refine but it is usually a non-discriminate ‘better’ and not because the overall chocolate is less bitter/astringent.  On the flip side I have observed a chocolate seems to become more bitter/astringent as time goes on in the refiner.  Notice I say seems.  From what I can tell chocolate isn’t actually getting more bitter.  Instead other flavors are decreasing so I am detecting more of the bitterness that is present.  And before you jump to a general conclusion that over-refining causes bitterness, these tests I performed were on both delicate chocolates (low chocolate, low fruit) and refined way way longer than anyone should refine.  I refined them over a week just to see if I could notice a difference.  In a chocolate that had a large chocolate flavor the overall flavor even after a week was basically unaffected.

Finally I want to touch upon conches. 

Melangers are not stunning conches.  The real truth of the matter is that they are not conches at all and I really wish people would stop using the term altogether as related to melangers or refiners.  One defining characteristic of conches is that they heat the chocolate.  Melangers do not do this.  Some heat is generated but rarely over 130 F and any actual conching is minimal in a melanger.

So here is a polite request.  If you are using a melanger say you are refining, not conching.  Ok?

If it is not obvious, I tend to be on the side of the argument that we have access to such great beans and make chocolate in such small (relatively) batches that there is indeed little need for conching now days.  I am unconvinced there is even much necessity of a separate conching step outside of a specific set of circumstances I’ll lay out in a moment.  In my experience if you are using good stock beans, fermented and roasted properly, than your chocolate canvas is basically finished and there is no need of remedial practices in a conch.  If the beans are not perfect or your roast created flavors you don’t particularly like much, extra refining (not conching if you are using a melanger) may help salvage the batch, but that is it.

I recently tasted some French chocolates that were refined on a five roller mill and subsequently conched (the one occasion I said I would bring up) .  I was completely underwhelmed and I was hard pressed to even identify the origins.  To my tastes it was too smooth and too lacking in flavor.   It was inoffensive and forgettable.  Nothing like damning it with faint praise.

The point is this is hard to achieve (note the 1 week refining test above) and was an active effort to make bland inoffensive/delicate chocolate.  You don’t need to worry about driving off delicate aromatics at 12 hours, let alone 24 or 36 or 72 hours.  Delicate is very relative.  If aroma or flavors are so delicate that they are going to be gone at 24 hours there is not much you can do about it.  And keep in mind aromatics and flavor compounds are two different things.

So what do you do if your chocolate is too bitter or astringent?  Learn from it.  Examine your roasting procedure or maybe your recipe.  If it looks ok, maybe consider that the bean you choose simply has more bitterness or astringency that you like.  9 times out of 10 I think it will be roasting related and even more likely that you treated the bean too delicately instead of too harshly.

Chocolate isn’t some delicate snowflake that must be coddled to maintain its pristine nature.  Just don’t abuse it.  Those are two totally different things.

Tomorrow I will be making the official announcement, but for those of you who made it this far, go checkout our new Chocolate Making Kits.  They are sort of paint by numbers kits to get you going.






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