Finer Cannabis Grounds Delivered Stronger Puffs, While Coarser Joints Lasted Longer
The way cannabis flower is ground may affect how quickly a joint burns and how much cannabinoid reaches the user in each puff, according to a 2023 Delic Labs experiment. The researchers found that finer particles produced more concentrated puffs, while coarser particles helped the joint burn for longer and delivered more THC over the course of the entire joint.
The study, published by Tim Sun, Hart Plommer, Sajni Shah and Markus Roggen, compared cannabis flower separated into particles measuring approximately 1, 3 and 5 millimeters. The team prepared 18 half-gram joints—three replicates for each particle size and flower type—and used a smoking machine to take standardized 50-cubic-centimeter puffs.
The machine collected smoke from the beginning, middle and end of each joint for cannabinoid analysis. Among the THC-dominant samples, 1-millimeter particles produced an average of about 0.67 milligrams of THC per puff. The 5-millimeter joints averaged approximately 0.51 milligrams per puff, while the 3-millimeter joints delivered about 0.31 milligrams per puff.
That higher per-puff delivery came with a trade-off: the finer-ground joints burned more quickly. The 1-millimeter THC joints took about 28 puffs to finish, compared with roughly 52 to 54 puffs for the 3- and 5-millimeter joints. Although the 1-millimeter joints produced stronger individual puffs, they delivered an estimated 16 to 19 milligrams of THC in total. The 5-millimeter joints delivered about 28 milligrams across the full smoking cycle.
The CBD-dominant samples showed a similar relationship between particle size and per-puff delivery. The 1-millimeter joints averaged 4.75 milligrams of CBD per puff, compared with 4.29 milligrams for 3-millimeter particles and 3.45 milligrams for 5-millimeter particles. The coarser CBD joints nevertheless delivered slightly more CBD overall—about 100 milligrams per joint, compared with roughly 90 milligrams for the finer samples.
The comparison between CBD and THC should be interpreted cautiously. The researchers used different flower types with different starting concentrations, so the finding that CBD delivery was higher in absolute milligram terms does not establish that CBD is inherently released more efficiently than THC. It also does not show that CBD-dominant joints produce a stronger subjective effect.
Perhaps the most important limitation is that this was a laboratory aerosol-measurement experiment, not a clinical study of people using cannabis. The measured milligrams per puff describe what the machine collected from the smoke—not the amount absorbed into a person’s bloodstream or the intensity of that person’s experience. Human puffing behavior, inhalation technique, tolerance, flower chemistry and combustion conditions can all change exposure. The National Institutes of Health has likewise noted that cannabis dose and effects can vary with the product, route of administration and individual factors.
The results do suggest that THC percentage alone does not determine how a pre-roll performs. Grind size, moisture, packing density, paper and the way the joint burns may influence both the concentration delivered in individual puffs and the total amount released. The researchers also observed substantial variation among replicate joints, indicating that there may be no universally ideal particle size for every flower type or product.
Further work could examine how grind size affects vaporizers and other devices, as well as smoke temperature, aerosol particles, terpenes and additional cannabinoids. For consumers, the study’s practical takeaway is limited but clear: finer flower may burn faster and provide more concentrated puffs, while coarser flower may produce a slower, longer-lasting joint. Neither result, by itself, guarantees a stronger or better experience.
Regardless of grind size, smoking cannabis exposes the respiratory system to harmful combustion products. Health Canada’s lower-risk cannabis guidelines advise avoiding burnt cannabis when possible and caution against deep inhalation or breath-holding.
