How much does 1 cubic foot of coffee weigh?

How much does 1 cubic foot of coffee weigh? - Your roasting questions answered

Dear Roast magazine,
I am looking for storage containers and silos for roasted and green coffee. I know what weights I need to store based upon my batch sizes, but when I look for either containers or silos the capacities are listed in cubic feet of space (ft3 ). My question is: how much does 1 cubic foot of coffee weigh?

Dear Roaster,
The measurement you are looking for is called bulk density. Bulk density is used not just for measuring when storing solids as in your situation, but is also often used in determining conveying rates and hopper sizes. Bulk density is the mass of a solid material (in your case, coffee) divided by the volume that the solid occupies (BD=M/V). In this case, mass refers to weight, and volume includes both the volume of the product and the voids between the product. Knowing this, how do you determine bulk density in cubic feet?

Determining Bulk Density in Cubic Feet

1. Know the volume of a cube: The volume of a cube is the measurement a side x 3 or side x side x side (a cube has equal sides).
2. Find a container that is 1 cubic foot--that is, 1 foot high, 1 foot deep and 1 foot wide; 1x1x1=1 cubic foot, or 1 ft³.
3. Fill your 1-cubic-foot container with coffee.
4. Weigh your container, remembering to net out the weight of the container itself. The bulk density will be the weight of the coffee held in your 1-cubic-foot container.

Variance

Depending upon how exacting you need to be with the size of your containers, you may need to remember that not all coffee has the same bulk density. Green coffee has a higher bulk density than roasted coffee. Ground coffee has a higher bulk density than whole bean. Dense, or more compact, beans have a higher bulk density than less dense, larger beans. For example, peaberry coffee has a much higher bulk density than, say, monsooned Malabar coffee does. The lighter the roast, the higher the bulk density for any single coffee. This true in both ground and whole bean. Shaking or vibrating a container will cause settling and possibly compression and, thus, increase the bulk density. This is especially true of ground coffee.

OK, so what does 1 cubic foot of coffee weigh? Here are some approximate ranges for the bulk density of coffee:

Green coffee 37-39 ft³
Roasted whole bean 22-24 ft³
Ground coffee 27-28 ft³

You can find these bulk density measurements, as well as those for other solids, at www.powderandbulk.com.