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I am a long time coffee roaster and know it is important to cool coffee as fast as possible. How quickly do I have to cool my cocoa beans? I’m worried they going to over roast if I don’t get them cool in a couple minutes, especially in the Behmor roaster.
I’m kind of surprised I’ve never answered this in depth before. Let’s do it.
First off the answer is that you should cool your roast as quick as possible without going crazy. That just means 3-15 minutes and that isn’t hard at all. It just means you want to actively cool the roast. That can be a fan blowing over them, or even just laying them out single layer with some space between the beans. Mostly you just don’t want a pile of beans sitting there in mass taking a couple hours to cool.
With that out of the way I want to talk about why do you want to actively cool your beans. It is sort of the coralary of why we roast the beans in the first place. We have just spend 15-20 minutes (25-45 minutes in an oven) adding a bunch of energy to the beans so that we can create flavors and also drive off moisture. You want to cool the beans to put a stop to those reactions.
You have the right idea that without active cooling you might over roast your beans. Well, that isn’t quite true. You are NOT going to over roast the beans by not actively cooling them. To over roast them you would need to keep heating them and cocoa doesn’t just keep heating up if you stop applying heat. Coffee if it is taken really far into the roast can start an exothermic reaction. That is just a way of saying that it starts to generate heat by breaking down the bean and if not stopped can over roast the beans and ultimately could catch fire. But that is at about 450 F. We are down at 250 F for cocoa. It doesn’t happen there. But what can happen is that chemical reactions can keep happening as long as the beans are hot and the longer they take to cool, the more reactions can occur. This isn’t inherently bad. The issue is that you end up with major reproducibility problems. One roast doesn’t taste like the next because the chemical reactions drifted out of control and the longer it takes the less likely it is the roaster will stop in the same place. Think about driving a car and coming to a stop. Which is more likely to work time and again? Holding onto the wheel and applying the break in a controlled manner or letting go of the wheel and just letting it coast to a stop? Clearly the first one is more reliable. It is no more complicated than that.
I want to touch on an interesting comment you made that I had thought had died a natural death in the coffee world. It is a fallacy that you have to cool coffee ‘as fast as possible”.
Years ago when I was deep into learning everything I could about coffee roasting I and a number of other people went down the rabbit hole of cooling research with the jumping off point of “cool your coffee as fast as possible”. This adage was in response to homeroasters letting their coffee at 450 F cool naturally over an hour or more. Doing so is a bad idea as the roasting process continues as I mentioned above and you get huge amounts of oxygen damage which negatively affects flavor. Humans being humans took it literally and instead of taking away “actively cool your coffee so the roasting process is stopped, instead of letting it passively cool for an hour” people went down the path of trying to get their beans to room temperature in 15 seconds. It was crazy. Hot beans dumped into ice cold cast iron pans, stirred vigorously with 100 CFM blown over them. And what we found out was one of two things. 1) it didn’t change the flavor at all compared to a 3-5 minute cool down and 2) in some instances the beans were under roasted because we were all so accustomed to taking a roast to a certain level and banking on a little further drift as the coffee cooled.
That second point is valid in cocoa too. Cocoa is much larger than coffee and it takes time for heat to penetrate to the core of the bean (thereby reducing astringency) and it takes time for moisture to migrate all the way out of the core. This is why I recommend letting beans stay open for at least 6 hours before winnowing. You are both letting the whole bean cool fully and for moisture to escape. It might surprise you to learn that of the 7-8% moisture in a raw cocoa bean, only about half of that moisture is driven off during the roast. It takes another 6-24 hours to for most of the rest to get out. If you go crazy and hyper quickly cool your beans you can actually retard that moisture escape process and end up with viscosity issues in your chocolate because there is too much moisture left.
The last thing I’ll say is watch out about overthinking something. In this case I’m talking about the Behmor 1600. I want you to consider is that I’ve suggested, offered and promoted the Behmor 1600 for roasting cocoa for over a decade and never once mentioned any deficiency in cooling. I also use it for ALL my evaluation chocolate, just using the standard profiles and cooling cycle. That is a huge amount of evidence that it works just fine, as is, without any intervention in cooling. Ok? Good!
The take away here (and really with all your timings) is consistency of your process.
Just actively cool them. Get them from 250 F to under 200 F in a couple of minutes, down to room temperature in 10-20 minutes, let them finish cooling to the core for another 6-12 hours and everything will be just fine.