How to Harvest & Prep Hemp Biomass for CBD Extraction Services

Ted Granbois, Oct 14, 2021 8:30:00 AM

Hemp producers who manufacture and market cannabidiol (CBD) and other botanical extracts understand the importance of starting with the highest quality agricultural product possible.

While premium quality biomass is essential, it’s not all that’s required to ensure quality, safety, and transparency in the final botanical extract.

Following the correct pre-processing steps can help you hand over the best possible raw material to your hemp extraction services provider.

Your tolling partner’s processing and extraction capabilities matter, too. They can help you deliver the best possible final product to your customers, faster and easier, and help you scale up production to meet demand for your CBD and herbal extracts.

Whether you’re a hemp farmer interested in creating your own branded extracts or a CBD entrepreneur developing a complete product line, it’s hard to over-emphasize the importance of properly prepared biomass in the herbal extraction process.

Let’s take a look at how to make sure your botanical biomass is the best it can be, and explore what it takes to transform that biomass into high quality hemp extract.

Growing and Harvesting Hemp Biomass

Producers select hemp seed with care to produce plants rich in CBD, low in THC, and well suited to their soil and weather conditions. Because of strict limits on THC levels, it’s crucial to limit stress on crops, and to harvest and handle biomass with care.

Factors that may cause higher THC levels in a hemp crop include:

  • Weather stress, such as drought, heat, cold, or flooding
  • Nutrient stress, such as too much or too little of specific soil components
  • Variety of seed selected

Some growers choose to test sample plants for CBD content on a weekly basis to determine the optimal time for harvest. While testing costs can add up, a one-percent difference in CBD content can have a significant effect on final product yield, and that can impact return on investment by thousands of dollars for as little as one acre of hemp. As with any agricultural product, weather can also impact the decision of when to harvest.

Many growers harvest plants using manual tools such as scythes or machetes. Five acres or more in production may be harvested mechanically using a specially modified combine.

Once off the field, floral hemp biomass is moved into an indoor drying facility such as a well-ventilated barn or shed. Experts advise breaking off and hanging individual branches (rather than whole plants) upside-down on wires, out of direct sunlight, with fans to aid in ventilation to minimize mold growth.

Ideal drying and curing conditions are between 60° and 70°F, at about 60% humidity, for a quality end product that is high in cannabinoids and terpenes. Drying usually takes about 3 to 5 days; in some circumstances, specialty hemp drying services may be needed to meet the moisture goal. Dried hemp biomass is then fed through a chipper for size reduction before it’s shipped to a toll processor for extraction and post-processing.

Storage and Shipping of Hemp Biomass

Depending on how it’s harvested, biomass may be baled, bagged, or even stored in bins. Consult with your toll processor to determine the most efficient bulk packaging method for you to ship and for them to handle your product in processing.

Properly dried and cured hemp may be stored in a cool, dry environment for up to 18 months — but take care to monitor for potency changes in stored biomass, since some compounds can increase while others can degrade, depending on temperature and exposure to light.

Qualifying Hemp Biomass for CBD Extraction

Licensed hemp growers are required to work with state or tribal departments of agriculture, or with the U.S. Department of Agriculture if appropriate, to comply with required THC testing that ensures their hemp products remain below the USDA’s 0.3% tetrahydrocannabinol requirement.

Growers pay for testing (and any retesting needed), and receive a letter of harvest approval from their state or tribal government. Biomass that tests above the threshold is required by most states to be destroyed, and cannot be processed for CBD extraction.

When working with a tolling partner, hemp producers or CBD product manufacturers need to provide:

  1. A letter of harvest approval from their state or tribal agriculture office, or from the USDA
  2. A certificate of analysis reporting <0.3% THC content via high performance liquid chromatography (HPLC)

The certificate of analysis is not only required to prove the biomass is compliant; the potency reporting it includes can help extraction experts predict processing times and expectations for product yield.

For hemp biomass to be ready for CO2 extraction services, it needs to have a moisture content below 15%, and a particle size range of 3mm to 7mm. Particle size is verified using a RO-TAP sieve shaker or similar equipment.

Important Tests, Analyses, & Certifications

HPLC, gas chromatography-mass spectrometry (GC-MS), and inductively coupled plasma mass spectrometry (ICP-MS) are three important analytical capabilities to look for in a toll processor, along with microbial testing capabilities. 

While processes like ethanol-modified CO2 extraction effectively kill bacteria and exclude mold from the final product, tests can be performed to identify and determine the potency of desirable constituents like cannabinoids and terpenes. Some of these tests can also be used to identify and quantify contaminants and their concentrations, such as:

  • Residual solvents
  • Pesticides, which can persist and carry over into extracted oils
  • Heavy metals, such as lead, chromium, cadmium, arsenic, and mercury
  • Microbes (presence and numbers)

Your toll processor should be able to provide testing and certificates of analysis for your CBD extract, batch by batch, which in turn enables you to provide transparent product and quality information to your customers and end users.

It’s also essential to know that your hemp processing services provider is certified and accredited to ensure products that comply with regulatory standards. Ask about Emerald Test validation, Hemp GMP certification, as well as the availability of organic and other specialty certifications, depending on target markets for your final formulations.

Working with a GMP-certified toll manufacturer ensures that all processes and protocols are documented and followed. That means straightforward product traceability, quality assurance, cleaning and hygiene standards that prevent cross contamination, and confidence that the CBD extract you receive is exactly what your toll processor says it is.

What About Post-Processing Services?

Many hemp entrepreneurs discover that the right toll manufacturing partner can save them significant time, money, and administrative burdens by adding downstream services such as:

The more processes you can keep under one roof, the more you stand to save — and that can make the difference between a hit and a miss when it comes to product margins and time to shelf. If you’re looking for more information on how to get the best possible products out of your herbal and botanical biomass using advanced extraction techniques, you won’t want to miss our Essential Guide to Herbal Processing. Click the link below to claim your free copy today.

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Posted in:Extraction