How much does voltage variation in a house affect roasting in a Behmor? Could it be as much as 2 additional minutes? I try roasting at 18 minutes but with most beans I don’t hear any beans pop at 18, and keep adding time on the fly at the end. It typically takes about 20 minutes with most beans to hear any pop, and I have gone as long as 22 without burning the beans. This seems to be the case with most of the non-Venezuelan beans I have used—Dominican, Ghana, Belize, Ecuador. Will all beans pop when properly roasted? You say that 16 minutes is the sweet spot for most beans but I never hear any of them pop that early in the roast. (I am always using 1 lb, program 2 as recommended)
First off, not all cocoa beans pop or crack. And I find that they tend to pop a little less in the Behmor compared to my own sample roaster or my production roaster.
Although there is not a 100% correlation, popping has to do with how fast heat is applied. The faster you apply heat, generally speaking, the more pops you will have. But you should keep in mind that pops or the lack thereof don’t correlate to a good or bad roast. The Behmor tends to apply heat a little more gently, so there are less pops. The same is true when you oven roast. It’s difficult to apply the heat fast enough.
Moisture also has an effect on popping. Sort of like puffed rice or wheat or popcorn. It’s that explosive release of water that you are hearing. So some drier beans like Nicaragua and Guatemala have a lower popping rate.
Humans it seems like definitive markers. Color. Sounds. Time. Temperature. But unfortunately cocoa isn’t cooperative that way most of the time. They don’t really change color when roasted. The time can vary greatly on your circumstances and it’s pretty hard to measure or know what the bean temperature is based on your ambient temperature. And cracks/pops don’t always happen. So what is one to do when roasting? Basically, use them all, plus aroma. With that last one being to me, the most critical in determining when you roast is done. And you have to back correlate.
What does that mean? It means roast 12-25 minutes, at 300-400 F (ambient), reducing the temperature as the roasts progresses (so you don’t scorch the beans) and listen for pops. Somewhere around 16-20 minutes, should you happen to hear pops, great, it means you are almost done. Go another 2-4 minutes until they smell like you want (not acrid) or pull them when they do smell acrid. And if they don’t crack, don’t sweat it. STILL go by aroma. And how do you know the aroma is right? You make a decision, try to remember the smell (and you have recorded the pertinent data, right? Origin,weight, time, temp) and make it into chocolate. Then…taste the chocolate and determine if you like it. If you do, well, where you picked to stop the roast was great. If it was a touch sharp or astringent, maybe roast a little more, if it was sharply bitter, maybe you need to go a little less. And one BIG thing. We are not talking about variations in 15 seconds or 30 seconds or even 1 minute. Cocoa just isn’t that sensitive. Often 3 minutes won’t make a huge difference. As you note. I say 16 minutes but you go 22 without burning. Very true. 4 minutes!
In some ways roasting can seem very mystical. Sort of like using the Force. But it’s just a matter of using ALL the data coming in, and mentally comparing it to what you know and have experienced on other roasts. And adjusting accordingly. Of course, the only way to get that experience is to jump in, take notes, don’t worry too much, and just do it. Yeah, it’s a bit scary, but that’s the reality. There is no one perfect way to tell you how to roast. Your equipment isn’t mine. I can’t tell you what I am smelling or what you will smell. I can only try to give you the tools to learn and gain your own experience. And I am always happy to do that.