Cannabis Quality Assessment and Grading

Prepared by the people, patients, and professionals of Dynamite Botanical

CANNABIS QUALITY ASSESSMENT AND GRADATION by the
DYNAMITE BOTANICAL COLLECTIVE and is licensed under a
Creative Commons Attribution-NonCommercial 4.0 International License.

How does a consumer know the quality of the cannabis they are buying? Until now one had to completely rely on  subjective speculation.  As the medical benefits of marijuana are becoming increasingly apparent, its use is becoming more and more widespread.  As the industry expands, the need for a reliable, objective grading system is necessary to protect the public interest. Other, similar industries are mandated to rate their products.  Consumers have a right to know the quality of their purchases.  The marijuana industry needs a uniform vocabulary for describing a product’s quality and worth. To meet these growing needs, the following Cannabis Grading System has been developed.  When used in conjunction with laboratory analysis this evidence based system constantly measures the quality of marijuana with objectivity, accuracy and precision.

 

Qualified laboratories regularly test different cannabis products for cannabinoid and terpenoid levels; microbiological screening; pesticides; and residual solvents to comply with state guidelines and to ensure the highest quality medicine.

 

The Cannabis Grading System directly correlates with the health and genetic makeup of the cannabis plant before harvest as well as the conditions and practices used for curing and storage. Industry experts agree, high quality medicine depends on high quality plants.  Plant imperfections reflect stress, disease, or improper cultivation practices.   

HOW ARE CHARACTERISTICS RATED?

Table 1 WHAT QUALITIES ARE RATED?
OLFACTORY Aroma and Taste: How does it smell and taste?
VISUAL Appearance: Bag Appeal, Color, trichomes, uniformity. Physical Inspection of bud/flower structure and calyx.
TACTILE Touch: What is the texture of the flower?  Is it spongy and moist? Does it slowly rebound to its original shape when compressed?

 

VISUAL: Imperfections and defects appear when the plant is stressed or mistreated. Many of these stressors will show as blemishes in the leaves and flowers.  Inspect the plant carefully for white, powdery spots, indicators of early blight (Alternaria solani).  Look for tiny raised blisters on the stems caused by  bacterial canker (Phytomonas michiganensis).  Check leaves for discoloration, uneven color or spotting caused by other diseases.  Dry, brownish or wilted leaves imply improper watering techniques.  Yellow hues suggest grow area got too cold.  Small  holes, black lines or dots are caused by insects and reflect poor plant health.  Excessively long, weak stems result from improper cultivation, inadequate pH of the soil, and overcrowding plants.

Appearance covers any visually apparent attribute or characteristic, the presence of trichomes as well as even, consistent coloration of the flower.

  1. Are flowers dense, not airy and fluffy?
  2. Are flowers free from discoloration due to oxidation, heat burns, or over/under nutrient stress?
  3. Is there a consistent, uniform look across the sample unit/pound?
  4. Is the color of the sample consistent with the known strain characteristics. [Leafly search]

 

OLFACTORY: Healthy plants have a strong distinct aroma that can be easily detected.  Plants with minimal odor are genetically flawed and do not provide quality medicine.  Each strain has its own characteristic aroma that can be distinguished with practice.  Experienced industry experts learn to recognize the exact strain of cannabis by aroma alone. With experience and patience examiners can become as proficient as fine wine connoisseurs in identifying specific characteristics.

 

TACTILE: High quality cannabis can have the consistency of dense fudge brownies. The bud should be moist and spongy feeling.  When pinched tightly and released the bud should slowly spring back to its original shape.  Feel the surface of the leaves and stems for symmetry and smoothness.  Small raised spots indicate puff daddy disease (exopuffdaddyities) a common disease of weak, overstressed pant.

 

Table 2
Symptoms   Cause
Firm, downward curling leaves, Over watering
Wilted brownish leaves

Yellowing, discoloration, or spotting

Under watering

Pests and insects

Burnt brown or yellow leaf tips Nutrient imbalance (too many, or not enough nutrients)  Excessive light
Yellowing leaves, weak stems, uneven coloring pH imbalance of soil or water  do you test the water?  Proper pH range is 6.5 to 7.8)
Loose, or airy buds, larfy buds. Brownish leaves, drooping leaves, excessive stems. Environmental extremes (Improper humidity or temperature)
Hermaphroditic Irregular light cycles, inadequate light, or genetic flaw

 

The following open-source, Cannabis Quality Assessment and Gradation system has been designed by DYNAMITE BOTANICAL to facilitate reliable and valid standards for measuring marijuana quality. The same sample should yield the same results every time and for every different examiner. To get started, samples being graded should be free of seeds (sensimilla) and without excessive stems or debris (shake, duff). To insure uniform quality, the sample should consist of at least, one pound of dried, cured, and manicured cannabis flowers. Storage best practices must always be adhered to.

 

Utilizing letter grades, all cannabis specimens start out with an ‘A’ grade in each category, or a AAA (triple A) for all three categories. For each negative attribute, the specimen grade will be marked down in that category. For example, in the Appearance category, flowers that are brown in color would lower the grade from an A to a B. If the same specimen also had airy, fluffy buds the grade would be further reduced from a B to a C. If another mark against the specimen was discovered, the grade would go down once again from a C to a D. Any grade below a D would be difficult to market but may be useful for making either concentrates or supplements.

 

Table 3 Cannabis Grading System
OLFACTORY (AROMA/TASTE) GRADE

(A)

TACTILE (TOUCH) GRADE

(A)

APPEARANCE (BAG APPEAL) GRADE

(A)

Does specimen have strong defined aroma? Is the texture of the buds moist and sticky? Are the buds solid and dense?
Is the sample free of odors such as hay, ammonia, pesticides or chemical contaminates? Is there a sponginess to the sample buds? Does each bud spring back to its original shape after compressing? Is the sample free from discoloration,

uneven coloring, spots or blemishes?

Does the aroma match the characteristics of the strain? Does the bud have a fudge like finish and consistency? Does the entire sample look consistent and uniform throughout?
Is there a substantial presence of trichomes?
GRADE TOTAL: GRADE TOTAL: GRADE TOTAL:

 

that mighty little plant