Science

What’s in your spark?

We’ve noticed that traditional flint lighters can leave behind a black residue after repeated use, and there’s been some discussion in the industry about whether that residue contains rare earth metals. Traditional flint lighters use a metal alloy containing rare earth metals, including cerium and lanthanum, to create a spark. Piezo-electric lighters work differently, creating a spark without the use of a metal flint.

Rather than rely on what we’d heard, we decided to have some independent testing done to see if these metals were actually present. We started by testing the residue left behind after repeatedly striking each type of lighter. We then took it a step further and had a second independent lab test the smoke from hemp pre-rolls lit with each type of lighter.

Here’s what the smoke testing found:

Results are per pre-roll. One nanogram (ng) is one-billionth of a gram.

Under the conditions tested, smoke from pre-rolls lit with a flint lighter contained measurable amounts of both metals, while smoke from those lit with a piezo lighter did not contain quantifiable amounts. We aren’t suggesting these results mean one lighter is safer than another. That’s not what we tested…but the results do show a measurable difference in the metals found in smoke depending on the type of lighter used.

**Results reflect the specific products and laboratory conditions tested and are not intended to establish health or safety differences between lighter types.

Independent Lab Reports:
Jordi Labs View the report
McKinney Specialty Labs View the report

Cones deliver more per puff.

A study commissioned by HBI Innovations and led by Drs. Riley Kirk, Miyabe Shields, and Allison Justice, along with Twinkle Paryani, compared RAW pre-rolled cones with straight joints to see whether shape actually makes a difference in THC delivery, terpene levels, and overall smoking performance. Researchers tested 12 joints using the same cannabis under controlled smoking conditions.

The results showed that cones delivered approximately 19% more THC and 30% more major terpenes per puff, while requiring fewer puffs to finish (20 vs. 23). Cones also showed much greater consistency between samples, with only 2.9% variability in smoke resin measurements compared to 16.5% for straight joints.

Here’s where it gets interesting. Despite the differences per puff, there was no statistically significant difference in the total THC or terpenes collected from either format. Essentially, both delivered similar overall amounts, but cones delivered more per puff and did so more consistently.

The takeaway is that something as simple as the shape of a joint can influence how it burns and how cannabinoids and terpenes are delivered. While the research is still preliminary, it’s nice to see some actual data behind a debate that’s probably been happening for as long as people have been rolling joints. And as it turns out, shape really does matter but it’s not quite as simple as one being better than the other.

Independent Lab Report:
Kirk and Shields Llc View the report.