Why should we worry about cocoa roasting after all?

27 Nov 2018

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Julien Simonis is an explorer of flavour, an experienced cocoa and chocolate Taste Professional. In this article, he tells us more about roasting. 

Roasting is a thermic process when the beans are (dry) heated. During this process, some aromatic compounds are created, some are modified, and some are lost. What you want in the end is to express the flavour potential of each bean to its maximum, keeping in the good stuff and creating more of it, and getting rid of the bad stuff. For the record, you have two other goals than flavour development for your roasting step: getting rid of water (reducing moisture to below 3% in the bean); and helping to guarantee microbiological safety.

Roasting is tailor-made craftsmanship

So the goal is maximizing flavour potential – remember, that is also possible through tailored small batch fermentation as explained in my previous article – through roasting.

Some beans have very delicate floral aromas that are very volatile. For these, the roasting will most probably have to be a very gentle one so that these floral aromas do not disappear. Other beans will present strong cocoa and chocolate flavours that could be enhanced through a strong roasting. Some beans presenting fresh fruit notes linked to the presence of certain organic acids will need a not-too-harsh roasting.

During this crucial step for the flavour, you can play with various technologies to achieve your dream taste. There is convection or conduction roasting, short or long, high or low, with or without water addition before or during roasting, … just to mention the most common ones. The precise impact of all these technological combinations is unfortunately not very well known.

Coffee, showing us the opportunities of the roasting technology know-how

When you compare with a “sister industry”, the coffee industry, the science behind roasting is extremely well developed, as is the technology. The flavour differences of the various coffee beans and the impact of different roasting methods on taste are well known and documented, and research is ongoing in these areas all around the world.

So how is it for cocoa? There is little public science available, and some private corporate research is certainly being carried out. For a ballpark estimation, in a “scientific literature” search engine (search done early October 2018), entering “Coffee roasting” produces 1019 articles; typing in “Cocoa roasting” only gives 212. What about another approach? Type “Coffee roasting research” into Google and you get 22,200,000 occurrences. Enter “Cocoa roasting research” and you get 2,780,000 (search done 16 October 2018). So we still have a lot to learn about roasting and its impact on the quality of the beans.

Let's explore the impact of roasting even more

To be honest, when tasting cocoa masses produced industrially, I find most of them over-roasted. I wondered if I was being too picky about taste, so I started testing on our pilot plant in Puratos. With our cocoa and pilot team, we adjusted roasting parameters in different ways, and the results were amazing. Chocolate made from the same beans (one made by us from bean to the bar; the other starting from an industrially produced cocoa mass), were completely different.

We finally re-discovered the fruitiness and the delicate floral notes of very special beans from Asia. We found intense raisins and prune tastes in batches from African countries. It is an ongoing exploration that makes my day each time I am fortunate enough to taste one of these batches.

The bottom line is that roasting is a very under-rated and under-studied step of the tree-to-chocolate process, that has a very important impact on flavour. If you go to the trouble of lovingly taking care of your fermentation in order to develop flavour, don’t ruin it all through a non-adapted roasting.

We therefore need to understand better what happens to flavour during roasting. For this we need more research, more sharing and even more passion for flavour!