Botanical Extraction

Bulk Packing Density and Cannabis/Hemp Extraction

Written by Caleb Summeril

Cannabis cultivation has developed in full over centuries. There are many methods and techniques, some common and some unique, employed by growers and farmers across the world. Cannabis extraction has less of a history but oftentimes more diversity in approach and preference. Bulk packing density of raw cannabis/hemp material can have a significant outcome on the extraction and the experimental extraction efficiency.

Bulk packing density relates to particle size, and how the ground biomass compacts during extraction. One simple way to increase packing density is to mill raw cannabis into smaller particles post-harvest. Biomass that’s not milled will have a packing density around 100-125 g/L while milling the material increases this density to 225-250 g/L. This indicates that milling cannabis before extraction can nearly double the overall efficiency through the increase in particle surface area. Cannabis milling machines are available in a variety of sizes to accommodate any existing extraction operation.

Depending on the extraction method, packing density can vary in relative importance. While it may seem that packing more biomass into an extraction vessel would provide the highest yield of cannabinoids in the crude extract, grinding the biomass too finely can be problematic. In supercritical carbon dioxide (CO2) extraction, for example, there can be channeling of the solvent in the vessel. The liquid CO2 will carve out a defined pathway and migrate down that channel, thereby contacting much less biomass, resulting in lower efficiencies and likely necessitating another run. The solvent can do this with smaller, “fluffier” biomass. Therefore, there’s really a sweet spot that should be targeted that enables as much biomass to be added to a vessel without facilitating solvent channeling.

While bulk packing density will be more of a concern to professional extraction operations over home extractors, it is still good to note the effect this relatively simple step can play in overall output on any level. Efficiency saves time for amateur extractors, and for professional set-ups, this can lead to a significant increase in potential profits. A focus on packing density is a small step any extractor can make to increasing their production capabilities.

Image Source: Fritsch-International

About the author

Caleb Summeril

Caleb Summeril writes creative copy, stories and songs from the mountains of Colorado. When not working on words, he can be found on global gallivants which fuel future endeavors. Learn more about his writing services at