What grass shouldn't smell like

People tend to compare cannabis strains to various smells: lemon, pine, clove, wood, skunk and even diesel. There are many things that cannabis can smell like, but some smells indicate a real problem, whether it's a quality defect or a health risk.

Here are the olfactory clues that something is wrong.

Summary table

It smells of freshly cut grass or grass clippings

The smell of freshly cut grass indicates that the chlorophyll in cannabis is breaking down into ammonia. This problem occurs during the curing and indicates that it is incomplete.

The curing, or curing, is an essential step after drying. Correct curing allows cannabis to mature, develop its full aroma and become more aromatic. keep its freshness for up to two years. Precipitated or poorly conducted, it produces cannabis that smells like grass clippings and will be unpleasant to smoke.

The process requires a controlled environment: ambient temperature, humidity between 55 and 65%, regular air circulation. After initial drying, the flowers are stored in hermetically sealed glass jars, regularly «aerated» (burping) for 2 to 8 weeks to evacuate excess moisture and renew oxygen.

Cannabis that still smells of fresh grass is not necessarily irrecoverable; a few weeks' additional curing may correct the problem. But cannabis bought in this condition indicates a producer who has cut back on curing time.

It smells of mildew or wet towels

The smell of a damp cellar, wet towel or undergrowth after rain indicates a mould contamination, mainly the Botrytis cinerea (gray mold) or’Aspergillus.

Contamination can occur during cultivation (excessive humidity, poor ventilation) or after harvest if drying is insufficient. It can also occur during improper storage, in a jar that is too damp, or in a hermetically sealed plastic bag at room temperature.

Do not consume Inhalation of mold spores can cause lung infections, particularly dangerous for immunocompromised people. Visual examination can help: molds form gray-white filaments that sometimes mimic trichomes to the naked eye, but can be distinguished with a magnifying glass. Molds have an irregular filamentous structure, whereas trichomes are spherical glands on a stem.

It smells of strong ammonia or urine

Distinct from the faint, fresh grassy smell of incomplete curing, a frank smell of ammonia or urine is a more serious warning signal. Possible causes:

• Excess nitrogen fertilizers not rinsed before harvesting, a grower who has not carried out the flush (rinse roots with clean water during the last few weeks of cultivation)
• Animal contamination (rodents, birds) during storage or transport
• Anaerobic fermentation in an excessively humid, oxygen-free environment

Do not consume Nitrogen fertilizer residues in high concentrations are harmful if inhaled.

It smells of chemicals, fuel or synthesis

An odor of solvent, fuel, burnt plastic or household products indicates the probable presence of residues of pesticides, or other chemicals used during cultivation and not removed before harvest.

This is the most difficult problem to detect with the naked eye or by smell, as some pesticides have no distinct odor. On the legal market, a certificate of analysis (COA) tests specifically for pesticide residues. On the illegal market, no guarantee is possible.

Do not consume Some pesticides (notably myclobutanil) generate toxic by-products when burned, including hydrogen cyanide.

It smells of plastic or synthetic

A plastic smell can have two origins:

• Unsuitable storage Cannabis stored for long periods in airtight plastic bags: the compounds in the plastic migrate to the trichomes and terpenes. Use only glass jars for storage.
• Damaged packaging Some low-end packaging leaves chemical residues on the product.

Less serious than pesticide or mold contamination, but an indicator of a poor supply chain.

It smells of dry hay, paper or nothing at all

Cannabis that has hardly any smell left, or smells of dry hay and old paper, has lost most of its terpenes, the volatile aromatic molecules that define the olfactory profile and contribute to the’entourage effect. Main causes :

• Too old Cannabis gradually loses its terpenes over 1 to 2 years, even when well preserved.
• Poorly preserved exposure to light, heat or air accelerates terpene degradation
• Irradiation Some industrial producers irradiate cannabis to eliminate mould, but the process also destroys a large proportion of the terpenes and alters the cannabinoids.

Odorless cannabis is not necessarily dangerous, but it will be significantly less pleasant and probably less effective than a fresh, well-preserved product.

What cannabis should smell like

For reference, quality cannabis has a complex, pronounced aroma, depending on the variety: citrus, pine, earthy, spicy, floral, fruity. Aromatic intensity is itself an indicator of quality. It reflects the richness of the terpene profile and the quality of the curing. Well-produced cannabis can be smelled even before you open the jar.