Anyone that roasts coffee knows that ultimate cup high quality from a given lot of coffee is greatly influenced by the farm itself — mother Nature and also farmers functioning in tandem. But, the course, that is the artisan who cooks up that coffee who deserve to either stand in the way of it"s potential, or masterfully unlock the covert treasure inside. That reasons, then, the the much more we understand about a details bean, the far better prepared we space to jinn up a excellent roast plan.

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One the the attributes that frequently doesn’t obtain the fist it deserves is p density, even though we are usually modestly tuned into it.

Roasters are usually fairly keen top top coffees get an impressive at higher altitudes. This is largely since those beans often tend to be denser. The cooler weather in higher altitudes, an especially at night, sluggish down the ripening the coffee cherries. This much longer time top top the plant converts to much more cell multiplication within the bean, yielding higher density.

Of course, altitude by itself does no dictate p density. You"ll notification this specifically if you are comparing one origin nation to another, so it"s great to measure up it. It could be tempting to disregard this because lab density meters room so spendy.

But, viola! measuring coffee bean density (or loved one density) is no out the reach because that any roaster. Listed below we will rundown two crazy basic methods.

But before we obtain to much more scientific measuring, take it a look in ~ this image:

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If girlfriend look at the two beans above, you can probably assumption: v which p is denser (exactly, the one on the left). An alert the center cuts of the two. This is a an excellent window into density. The bean on the left has a an extremely tight facility cut and also it simply seems compressed and also tight. The bean on the right has a comparatively open facility cut, saying a an ext relaxed and also open bean. We provided our mad-science range to sweet these and, interestingly, if the p on the best is rather a bit larger, both bean (coincidentally) weighed precisely the same!

Let’s take into consideration two things things prior to we gain to measure density:

First, bean thickness matters. Really, that does. Thickness simply refers to the concentration of issue in a given space. For green coffee, higher density tells us there is a better concentration that cells and a more compact cell framework than its lower density counterparts. Just how that bean absorbs energy, withstands pressure, cracks and develops is walking to differ from bean with reduced density. (We nearby this write-up with a couple of takeaway considerations for enhancing your roasting finesse.)

Secondly, because that roasting coffee we mainly only care around relative density. In various other words, to understand how thickness influences roasting procedure and cup quality amongst various beans, it’s really only necessary to know how density stacks up in between each coffee. Together an example, if i’m at the gym round off up some guys for a pickup video game of basketball, ns trying to recruitment the players who space taller than the various other players…I don’t care to know their really height.

The point around this all being relative is important since of the two approaches of measuring we outline below. The second technique is technically an ext accurate, however the first is easier and generally just as useful. And also since both techniques reveal just how your beans stack up against every other, one of two people works.

Doing Science

Measuring thickness is about the ratio of mass (in our case, just weight) come volume. This deserve to be pounds per cubic foot (lb/ft3) or, an ext commonly in activities science, kilograms every cubic meter (or diminished down to grams and also milliliters). The second technique below counts on water and we note exactly how the metric system displays its brilliance as soon as it involves measuring water due to the fact that 1g that water = 1mL the water, i m sorry is the same as 1 cubic centimeter of water which way that the thickness of water is 1g/mL. (And, by-the-way, 1 calorie is the energy required to raise 1g of water 1°C.) Amazing.

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Method 1 - Measuring cleared up Density

Tools needed: i graduated cylinder ($6 ~ above Amazon or see different below*), laboratory scale

To measure the density of eco-friendly coffee beans, fill a graduated cylinder (tube v measure present on it) v a well-known weight of eco-friendly coffee. Keep in mind the volume reading. You can likewise do this in turning back (as we did) by filling the cylinder to her liking, note that to fill volume value, then weigh the coffee. Easy.

Do the math.

Weight (g) ÷ Volume (mL) = density (g/mL).

You’ll notice that through a narrow, graduated cylinder the beans execute not “pack” in all the well and if you took numerous readings through the same coffee it wouldn’t be how amazing to come at slightly various readings (it"s a good practice to take several readings and also average them). Also, the more you fill up the cylinder, the greater the accuracy (we fill it come 100mL, climate weighed the coffee).

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We took some readings the four various coffees in our laboratory and listed the results below. Again, together you can see, the relative density of these four coffees is noteworthy. Correlation in between density and also altitude no perfect, either, as the highest grown coffee (Ethiopia Natural) had the 2nd lowest density readings that this lineup. The only washed coffee in our lineup had the highest density. This is not surprising.

But look in ~ the data. This are material differences. This range definitely shines a irradiate on something that have to influence exactly how we strategy roasting them (they are provided from lowest to highest possible density).

CoffeeAltitudeWeightDensity% Change
Thailand - Honey1,200m65.6.656g/mLN/A
Ethiopia - Natural1,800m67.6.676g/mL3.05%
El Salvador - Natural1,400m70.3.703g/mL3.99%
Kenya - Washed1,600m71.0.710g/mL1.00%
**Kenya v. Thailand8.23%**

Method 2 - Measuring thickness by Displacement

Tools needed: graduated cylinder ($6 top top Amazon), laboratory scale, Water

To measure the density of green coffee beans, fill a i graduated cylinder (tube through measure present on it) something much less than full; keep in mind this value. Then include a well-known weight of eco-friendly coffee beans to the cylinder and watch the water rise! Now, simply subtract the original water volume analysis from this new water volume reading and also this net value (difference) is the lot of water “displaced” by the bean — just how much volume the bean occupy in the cylinder.

In our test of the very same Thailand coffee above, us filled the cylinder halfway with 50ml the water, then added 30g of eco-friendly coffee beans and watched the water level rise to 75.5mL. The displaced water was, therefore, 25.5mL (75.5mL - 50.0mL = 25.5mL).

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This method of measure up bean density is reasonably accurate. Due to the fact that the water operation in between all the beans, we have actually a very an excellent read on the really volume of beans in the cylinder. The downside of this technique is the we simply trashed 30g of environment-friendly coffee—and if we’re measure up the thickness of the pricey Geisha…

In any case, let’s carry out the math: 30g ÷ 25.5mL = 1.176g/mL.

Notice the difference from the analysis of the exact same coffee above! This sets up our closing 2 points.

First, pick one an approach of measuring density and also stick with that. You won’t be able to accurately to compare one bean thickness to the next if you’re mixing techniques since the "displacement method" will constantly yield greater (more accurate) values than the “freely worked out method." Again, the density measurements native the displaced water an approach versus the worked out volume measure of the Thailand coffee above (.626 g/mL and 1.176 g/mL, respectively) is huge. The 2nd reading is practically 80% higher!

Secondly, keep track the this data in her roast log. If friend don’t maintain a roast log, start preserving a roast log. Seriously. The value of being able come go earlier to your notes and also figure things out is one invaluable tool for recurring learning and pinpointing why other went so well…or so poorly. Friend can begin to answer the elusive, “why go this 2nd roast batch of that very same damned coffee come out so flat!?”

Here’s a roast log sheet we put together for our use. Our actual “log” is a file containing this roast sheets and cupping score sheets for every our coffees. I can practically promise you, if you maintain notes, girlfriend will recommendation them!

As you roast with thickness in mind, here are a few basic considerations for how thickness influences roasting:

As we noted above, dense beans have actually a tighter, more complicated cell structure. This structure packs in an ext potential for sugars and also acid to develop during a roast;

Denser beans are going to command heat much more efficiently and will usually roast a little faster;

Soft beans might take longer to roast, and with warmth transfer occurring within the bean an ext slowly, higher roasting temps may cause scorching and also other uneven outcomes (see our post on roasting naturals which have tendency to have actually lighter and more varied density).

So, density alone will certainly not drive her roast plan, however it should certainly be miscellaneous that influences it. Again, the much more diligent you space in recording your roast data, the much more you will certainly learn about how the many variables play a role.

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Happy roasting!

Note: because that the freely settled technique described above, you don"t really require a graduated cylinder. You can use any type of straight-walled cylinder such as a piece of pvc pipe with a basic on it. You simply need to recognize how countless mL of water the vessel holds. If you select to do this, aim because that a larger diameter (up 3" or 4" and maybe cut to 4" to 6" in length) for much more consistent results. Fill it come the brim with water and weigh the contents, remembering that mg of water = mL the water. Compose this mL number ~ above the pipe and that is your constant reference. Then, proceed as described over by filling the pipe flush with green coffee, weighing the coffee, then dividing that weight by the variety of mL that water the pipeline holds. That"s her g/mL thickness value.