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How to Measure Green Bean Density - Roasting Coffee at Home

This is the second video in our roasting coffee at home series and in this one Luke is teaching you how to measure green bean density. Learning to calculate and measure density in a green coffee bean is important if you want to track your roasting progress week in week out so you can dial in the results and improve your roasted beans.

It's actually quite a simple process and in this video Luke will show you exactly how its done.

Hope you enjoy the video. 

Video Transcript 

Today, I'm going to teach you how to measure your green bean density at home
and tell you why you need to understand it. 

So, it's pretty easy when we look at beans, they're grown at all different places around the world, and those specific regions have a characteristic which is going to affect the bean. Their altitude, the climate it is, whether it's warm, cold that will essentially change the cell structure of the bean as it grows. 

So a higher altitude with a colder night will make a much more denser bean. 
If you think about camping, if you go up high altitudes and you light a fire, those logs burn all night. But down at low altitudes, they can just burn like a  matchstick so quick.

It's because the trees up high grow slower and take longer, and they get essentially more rings inside. They're the denser actual tree, because of the years it takes to grow.

So it's the same principle for the coffee bean. Now why do we need to know that? 

It's because when we're roasting that density, we have to combat that with the energy or the heat that we're going to apply to that bean and that will be affected throughout the whole roast curve. So whether it's drying the mailard, the development, we can change those because we know it may need more heat.

Now I know that Ethiopian beans right on crack need that extra bit of kick just to get through first crack, but something like a Colombian, which we find is a little bit less dense.

We want to hold off that heat through first crack to make it a bit easier. So we've got a couple of things here nice and easy to teach you how to do this at home.
Firstly, I'll show you what we do commercially. We have the Lighttells ND 500. It's a really easy unit to use. This does moisture and it does density.

So simply, we fill up our little measuring jug. We pop it in. Lift out our little brass stopper there. Now that's just turned off on me. So we just got to wait for a sec for it to turn back on.

So that's warmed up now, and it's ready to go. We're just going to tip in our green bean, open up our little brass stopper. The beans are going to go into basically a little bucket and when we hit measure that will give us the green bean moisture and the density. The density is measured in grams per liter of volume.

So this is showing 14.1% moisture at 783 grams. So it's quite a dense coffee. 
Now a way to do it at home is I'm going to teach you a little hack. So you just need to get yourself some sort of device or tube, which is exactly one liter. So we've got a bit of PVC pipe here. We've got our green bean and grab yourself a set of scales. So pop it on to the scale. Make sure you tare that off. You're going to grab your green bean and you're going to have to fill it up. And if you got a little shaped like this, make sure you do tap that down because we want to fill it the best we possibly can. Keeping in mind when we're doing a litre a litre of liquid will fill every piece of space, where green beans going to have some gaps in between it. So take a little bit time just to make sure you get it all in there. 

There we go. And then put it back on your scale, and we've got 722.9, so 723. So you can see a manual way you can do it at home. It's pretty close to the digital. Obviously, the digital is going to be far more accurate. But if you keep using this system at home every single time, that'll be the same measuring tool and graph and points that you can use to measure your coffee.

So guys, I hope this little device is going to help you change your roasting at home. Hey, if you've got a little device that you use similar to this, we'd love to hear about. Leave us a comment below. And if you've got any questions, yeah, we'd love to hear them as well. 

Thanks very much for watching, guys. 


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