Should You Automate Cannabis Trimming?

Columns - Tomorrow in Cannabis

As technologies continue to mature, it might be time to reconsider some industry biases against mechanization in the post-harvest process.

August 17, 2022

Hoptocopter | iStockphoto

After the quality of the cultivation process, the handling during harvest, and the care taken during drying and curing, the biggest determining factor regarding a cannabis crop’s market value is the visual bag appeal of the finished product. This bag appeal typically is determined by the trimming quality of cannabis flowers.

Proper trimming is what customers associate with and expect from a quality product. Trimming is one of the final checks in cannabis production and is critical to not only producing a more aesthetically pleasing product, but also to preserving resin glands (trichomes), where the bulk of the cannabinoids and aromatic terpenes are stored.

The goal of trimming is to remove all primary and secondary leaves and any plant material that does not have resin glands covering its surface. For decades, legacy growers have trimmed cannabis by hand, and hand trimming has long been associated with top-quality craft cannabis. It continues to be widely considered the best method to trim cannabis to preserve trichomes.

But increased consumer demand for a range of high-quality cannabis end products, and the increasing average canopy size (as reported in Cannabis Business Times’ 2021 “State of the Cannabis Cultivation Industry” report) has spotlighted the obstacles that result from hand trimming: It is extremely time and resource intensive (potentially creating a bottleneck in post-harvest) and highly prone to producing inconsistencies in quality.

This bottleneck has allowed for the adoption of differing commercial methodologies for drying, curing, and trimming. In turn, these methods raise multiple questions that need answers before a grower begins a harvest, namely:

    Harvesting: Should a producer cut and hang the whole plant? Just the branches? Or utilize a bucking machine to remove buds to be trimmed and dried on racks?
    Trimming humidity: Wet or dry trim?
    Difference between hand- and machine-trimmed cannabis?

Let’s tackle these one at a time.

halbergman | Adobe Stock

1. Harvesting: Whole plant or bucked buds?

A commercial operation must intelligently pre-plan harvest methods, especially if done in a controlled environment.

Whole Plant

Some hemp, outdoor, and many other growers prefer to cut and hang the whole plant upside down on custom hanging racks from floor to ceiling. Some utilize the same rack system to only hang the individual branches that have been cut from the main stalk. Others buck off the buds and dry on racks. What route a grower chooses ultimately depends on the available drying space and extraction methods (if any).

A hemp grower with unlimited space typically will choose to hang whole plants on floor-to-ceiling racks, and some outdoor cannabis growers do the same if space permits. Typically, most commercial indoor, outdoor, and greenhouse growers hang only branches, not whole plants, on clothesline-style lines, or on custom mesh racks where branches hang upside down to facilitate proper airflow and drying. The buds can then be removed from the stem by hand or bucking machine and prepared for trimming.

Bucked Buds

Movable drying racks with mesh airflow shelves allow for a much more efficient utilization of available space, but require that buds be removed from stalks. By eliminating the stalk and branch stems, the grower eliminates a portion of the moisture that would otherwise need to be removed from the environment, thus expediting drying. Also, more product can fit in a given space by eliminating stalks/stems and by placing buds onto movable racks, and these racks can allow the grower to easily move product from one place to another without dislodging and losing trichomes.

The choice between hand-bucking and automating the process mostly comes down to the volume of biomass that needs processing. Some growers have reported experiencing production bottlenecks during the bucking process for which automation can be a solution. Upfront purchasing costs can also be a factor for leaner operations.

2. Trimming humidity: Wet or dry trim?

Some growers choose to trim buds while they are still wet. Wet trimming, especially when buds are very sturdy, can allow for the preservation of the bud structure. Fluffy and airy flowers, once dried, can break down and flake off their stems during trimming.

Others choose to trim the buds after they have dried. Drying flowers before trimming them can streamline the trimming process. Dried sugar leaves and unwanted biomass becomes easier to both hand- and machine-trim after the product is dried.

A third group actually utilizes the principal methods of both by placing bucked wet buds into a trimmer that utilizes nitrogen gas to freeze-dry the flower’s surface, solidifying the resin glands and making the small leaf tips brittle so that they break off in the rotating trimming machine. This method is said to increase trichome preservation while eliminating the leaf tips.

All three methods have a purpose to suit a given situation, with the best method being what ultimately works best for you while efficiently producing a quality finished product.

Jantira | Adobe Stock

3. Hand or machine trim?

Most knowledgeable consumers equate hand trimmed cannabis with a superior product, to which I agree to some extent. Having been a grower that has trimmed my own cannabis for more than 40 years, I have witnessed the superior quality of a properly manicured flower. A great hand-trimmer can be worth their weight in gold (or bud).

But as cannabis operations’ size and scale increase, the hand-trimming process and expense can be a gargantuan investment. As commercial operations often stagger harvests, a harvest and trim can take place weekly or biweekly. Some operations are in a constant state of drying and trimming, which can take its toll on trim staff as trimming is a very monotonous task.

According to Cannabis Business Times’ 2021 “State of the Trimming Market” report, the median amount of cannabis that trim staff were expected to process in a typical shift was 2 pounds, and the average shift length reported was 7.3 hours. Assuming hand trimmers can produce up to 2 pounds in a typical 8-hour shift, it would take 160 human trimmers to equal the output of some trimming machine models over the course of the workday, according to the report.

More than 15 years ago, companies attempted to mechanize the trimming process via automated trimming machines. When these systems first were launched, many criticized them for destroying resin glands and bud structures. However, since those early models hit the market, companies have been diligently perfecting their machinery for optimal performance and efficiency, with a focus on the preservation of all available trichomes on the surface of the plant after the removal of any undesirable material.

Keirton, a manufacturer of trimming and bucking equipment, in partnership with MB Labs and Caro Analytical Services, compared the potency test results of hand-trimmed flower with that of machine-trimmed product over two sample years (2018 and 2020). While the 2018 tests showed THC levels for machine-trimmed flower dropped by up to 3.8%, technological advancements and engineering upgrades saw that discrepancy slim down to 0.6% in 2020.

These cost-savings are significant to large-scale, commercial cultivators trying to be as efficient as possible without significantly compromising the quality of cannabis they produce. Some producers have chosen to employ both methods, hand trimming premium cannabis while machine trimming other cultivars.

Producing craft quality cannabis on a commercial scale will become more important as competition for sales and shelf space increases. Utilizing today’s (and tomorrow’s) technologies is essential to increase the probabilities for large-scale cannabis growers to produce the best possible products efficiently and on a commercial scale.

Editors’ Note: This article first appeared in the October 2021 edition of Cannabis Business Times.

Kenneth Morrow is an author, consultant and owner of Trichome Technologies. Facebook: TrichomeTechnologies Instagram: Trichome Technologies k.trichometechnologies@gmail.com