LetterPress Chocolate begins conching for flavor development
What is chocolate conching? And why haven’t we ever done it before?
In the most basic terms, conching is heat + aeration. But let’s back up a moment and talk about the bigger issue.
What is the problem?
All cacao we work with has been fermented. During the fermentation stage, acedic acid permeates the cacao beans. Acedic acid has a strong vinegar smell and adds an unpleasant bitterness and sourness to chocolate. It basically tastes like sour cherries. While some cacao beans naturally have a red berry note, generally speaking, this is an off-flavor that needs to be removed in order to get the real flavor profile underneath. Our opinion is, we’re paying all this money for these beans, why not let them be fully expressed? Next time you taste a poorly-made chocolate bar, see if you taste that sour cherry note. It’s a flaw, not a feature.
What is the solution?
We need to use heat to remove the acedic acid. While this can partially be achieved with roasting, that really only removes the acedic acid on the outer portion of the beans. In order to remove more of it, we need to heat up the cocoa mass during the milling stage.
At our scale, most chocolate makers use a melanger which is basically a large bowl with a stone base and two stone wheels which crush the cacao beans down into liquor, then sugar and other ingredients are added. The problem with these machines is that it’s relying on open-air exposure to volatilize the acedic acid, but this take several days and really doesn’t work. We know because we used this method for almost 5 years. While you can get decent results, and we’ve certainly won our fair share of awards using this method, we do not recommend it. What we really need is heat and air. That’s what conching is. And because we’re now adding heat during the milling stage, we can back off on the amount of heat we’re using during the roasting stage. The result is much finer flavor and more indicative of the true notes of the cacao we’re sourcing.
Using Diamond Custom Machines’ Rapid Refiner, we do a few things. First, we adjust the heat to over 150F. Acedic acid volitalizes at 150F so any value above this is a great starting point. You cannot go to hot though because the delrin and epoxy (Polyoxymethylene) becomes soft above 170F and can separate from the stones. We found at least 160F is a good starting point. Next, we load the nibs into the grinder but do not turn the tensioner screws down at all. I cannot stress this enough. We let the weight of the stones and gravity do the work. This reduces shear and viscosity when we add sugar later, but more importantly, it releases the acedic acid slowly over time rather than all at once, so that the refiner and heat work together.
We are proud to bring you a new lineup of our bars using this method – our two new bars this month, Tingo Maria from Peru and Bachelor’s Hall from Jamaica both were conched to bring out their nuanced flavor profiles.
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