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Can You Tell Quality From Ash Colour?

When it comes to assessing cannabis quality, there are many ways to grade this flower known as the “paradise plant.” Cannabis flower can be assessed by performing a physical analysis of the herb, which analyzes bud integrity to trichome expression, or by an adopted method from cigar culture that includes evaluating burned ash colour.

The Cigar Trick

When reviewing cannabis flower firsthand, educated consumers will often look to a cultivar’s potent smell or loudness, which is a strong indication of a premium grown product. When not able to rely on one’s sense of smell, some consumers may gauge potency ratios, explore listed terpene content, or search out a particular cannabinoid through Certificates of Analysis. The more traditional consumer, however, will inadvertently grade their flower by grinding up their fresh bud, rolling it into a joint, and then find that missing lighter: aka perform a “burn test”.

Performing a burn test will highlight the taste and burn experience, but not necessarily the effects felt afterwards. This method of determining flower quality consists of sparking up your joint to interpret the smoke experience and its endurance of flavour, and to inspect the ash colour as it exposes itself, but herein lies a cannabis ash debate.

It is said that combusted white or near-white ash is a representation of clean flower. However, if you notice “salt and pepper” or black ash during your smoke session, then this is noted as having potentially unwanted contaminants or nutrients leftover in your cannabis. The implication drawn from implied inferior ash colour is that chemicals used during the growing process are still present in the plant because of improper flushing and/or curing techniques and that residual chemicals may lead to harm when inhaled by the end consumer.

But is this an accurate representation of ash colour?

Is Flushing Flawed Science?

For those unaccustomed to cultivation practices, flushing is the process of feeding a cannabis plant only water and no nutrients for the last one to two weeks of growth before harvest to “flush out” any unwanted nutrients or potentially harmful chemicals. Flushing is regarded as a critical step by many growers and is considered to influence the flower’s overall smoke quality, but not all growers will agree with this practice as some feel it is an unnecessary step in the cultivation process. With a lack of consistent research readily available, some growers claim that flushing science is flawed and regardless of flushing, their flower will still burn white ash if it has been properly grown to begin with.

So, if flushing is not a proven direct factor in determining ash colour, then what about curing?

Curing cannabis removes unwanted moisture, sugars, and starches under controlled conditions to preserve desirables, such as cannabinoids and terpenes. In theory, curing, or “burping,” will lead to whiter ash while preserving the taste and aromas desired by many, but not all will take the time required to invest in a proper cure since it is an additional step in the drying stage. If excess undesirables are not absorbed during the cure, then they will remain in the flower, and this can lead to a harsh smoke experience. Due to a lack of scientific evidence, we do not know the exact reason for varying ash colour, and it is likely a combination of several factors, although curing does offer improvement to flower quality.

With a wide variety of growing methods and nutrients being used in our industry, ash colour alone is unlikely to determine the quality of clean flower, but if you find yourself gravitating towards cannabis that offers intoxicating aromas, flavours, and effects, then trust what stimulates your senses.

Kelsey Cannabis is a certified cannabis Educator, Speaker, and Consultant who makes plant science more approachable for patients, professionals, and recreational users.

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