Why the number on the screen is not the one that acts

The display shows what a sensor reads, and the sensor is not in the material. It is in or near the heating element, which is a different place at a different temperature, and the difference can be substantial.

That gap explains most of the confusion about vaporisation temperatures: why published charts do not transfer between devices, why the same setting behaves differently on two units, and why comparing numbers across devices is largely meaningless.

This page covers where the sensor actually sits, what determines the material’s temperature, why boiling point charts mislead, what conduction and convection change, and what to do instead of chasing numbers.

⚠️ Scope. This page describes a process and what can be verified from documents. It does not describe what a product does to a person, gives no amounts, and does not replace a healthcare professional.

🔴 Where the sensor is

Not in the material

Placing a sensor in a moving airstream full of plant matter is impractical. It sits in or beside the heating element instead.

What it therefore reads

The element’s temperature, or the temperature of the air leaving it, depending on the design.

What the material is at

Lower, by an amount depending on airflow, material density, moisture and how long the device has been running.

How large the gap is

Variable and frequently substantial. It is a property of the device rather than a fixed offset.

What determines the material’s temperature

Airflow rate

Faster draw means more heat carried into the material and less time for it to equilibrate. Both effects matter and they act in opposite directions.

Packing density

Tightly packed material heats unevenly and restricts airflow. Loosely packed material heats faster and holds less.

Moisture content

Water absorbs heat as it evaporates. Damper material runs cooler than the same material dry, at the same setting.

Session duration

The first draw and the fifth are at different temperatures even with the display unchanged, because the mass is still warming.

Conduction and convection

Conduction devices

Heat passes from a hot surface directly into material touching it. Simple, inexpensive, and prone to uneven heating.

What that produces

Material next to the wall considerably hotter than material at the centre. Stirring between draws is the standard correction.

Convection devices

Hot air passes through the material, heating it throughout. More even, more expensive, and more dependent on airflow.

Hybrid designs

Most devices are some combination. The proportion determines how much the displayed number relates to anything.

🔴 Why boiling point charts mislead

What they show

The boiling points of individual compounds, measured in isolation, at atmospheric pressure.

What that describes

A pure substance in a flask. It is a real physical property and it is measured under conditions that do not apply.

What actually happens

Compounds sit in a mixture, within plant tissue, in a moving airstream. They leave progressively rather than at a threshold.

The consequence

A chart implying that a specific setting releases a specific compound is describing something that does not occur that way.

What does happen with temperature

Lower settings

More of the volatile fraction, less of everything else. The aroma is fuller and the material lasts longer.

Higher settings

More of everything, faster, including degradation products from the plant material itself.

The progression

Continuous rather than stepped. There is no threshold at which one thing stops and another starts.

What that implies

Choosing a setting is choosing a balance rather than selecting a compound. The vocabulary of targeting is misleading.

Why device numbers do not transfer

Different sensor placement

Two devices reading the same number can have material at quite different temperatures.

Different heating methods

A conduction device and a convection device at the same setting produce entirely different results.

Different airflow

Draw resistance and path design change how much heat reaches the material.

The practical rule

A setting learned on one device is worthless on another. Recalibrate by experience rather than by transferring numbers.

Finding a setting on your own device

Start low

Below where you expect to want it, and work upward. It is easier to raise a setting than to undo an over-heated load.

Change one thing

Setting, or packing, or draw technique. Changing two at once tells you nothing about either.

Note what happens

Setting, material, and a word on the result. Three items, and after a few sessions you have a calibration for that device.

What you end up with

A working range for your device with your material, which is the only useful form this information takes.

Signs of running too hot

The taste

Harsh and increasingly burnt. It is the most immediate and most reliable indicator.

The material afterwards

Dark brown to black rather than evenly toasted. It is visible and it is unambiguous.

The vapour

Denser and harsher. Density is frequently mistaken for quality and it mostly indicates temperature.

What is lost

The aromatic fraction goes first at any temperature, and running hot removes it in one session rather than over several.

Signs of running too cool

Little vapour

The obvious one, and it is sometimes a temperature problem and sometimes a packing or airflow one.

Material barely changed

Still green after a session, with most of what was in it still there.

The correction

A modest increase, one step at a time. Large jumps overshoot and the overshoot is not recoverable.

The other possibility

Damp material, which absorbs heat as its water evaporates and behaves exactly like a device running cool.

The grind, which matters as much as the setting

Why it does

Particle size determines surface area and airflow. Both affect how heat reaches the material more than a step on a dial does.

Too fine

Packs densely, restricts airflow, and passes through screens. It also heats unevenly despite feeling like it should not.

Too coarse

Heats on the surface while the interior stays untouched, which looks like a device running cool.

The interaction

A setting that works with one grind does not with another. When results change unexpectedly, the grind is worth checking before the temperature.

Moisture, which matters more than people expect

The mechanism

Evaporating water absorbs a large amount of heat. Damp material diverts energy away from everything else.

What it looks like

Weak vapour at a setting that previously worked, with the material appearing barely used.

The correct range

The same range that suits storage. Material held properly performs predictably.

What over-dried material does

The opposite: it heats too fast, scorches at settings that were previously fine, and tastes harsh.

What the material looks like afterwards

The useful check

Open the chamber at the end and look. The colour of the spent material is the most direct evidence of what temperature it actually reached.

Evenly toasted

Light to medium brown throughout, with no green centre and no black edges. It is what a correctly run session leaves behind.

Green in the middle

The load did not heat through. Either the setting was low, the packing was too dense, or the material was damp.

Black at the edges

Contact with a hot surface, characteristic of conduction devices. Stirring between draws is the standard correction.

Why density of vapour misleads

What people read it as

Strength. A thick visible cloud feels like a better result and is frequently taken as one.

What it actually indicates

Temperature, principally, and to a degree the moisture content of the material. Both raise visible density without raising anything else.

What is happening at that point

More of everything is coming off, including the degradation products that a lower setting would not have produced.

The better indicator

Taste, and the state of the material afterwards. Both are more informative than how much is visible in the air.

The session, and how it changes

The first draws

The material is still warming and the aromatic fraction leaves first. These are the draws where the character is.

The middle

The steady part, where the load is at temperature and delivering consistently.

The end

Diminishing returns, and the point at which people frequently raise the setting to extract the last of it.

What that costs

The final increase produces the harshest part of the session for the least return. Stopping earlier is generally the better trade.

Stirring, and why it matters

On conduction devices

Essential. Material against the wall is far hotter than material at the centre, and stirring redistributes it.

When to do it

Between draws, once the load has been running. Early stirring on a cold load achieves nothing.

On convection devices

Less critical, and still useful where the load has settled and compacted during the session.

What it produces

A more even result and a fuller extraction from the same material at the same setting.

What no device tells you

The material’s actual temperature

Which is the thing that matters and which no consumer device measures.

What was extracted

Only the residue gives an indication, and it is qualitative.

What was lost

Aromatic compounds that left at the start of the session, invisibly.

Why that is acceptable

Because the method described here works without any of it. Observation of taste and residue substitutes adequately for measurement nobody can make.

Why this format is documented worst and understood best

The documentation position

Nothing on any certificate concerns how a device delivers material, and no consumer device measures the quantity that matters.

Why that turns out not to matter much

Because the feedback is immediate and legible. Taste tells you within a draw, and the residue tells you within a session.

The contrast with everything else

Elsewhere in this subject the important variables are invisible and the documents are the only access to them. Here the reverse holds.

What follows

This is the one area where personal experimentation genuinely outperforms published information, and where a notebook beats a chart.

The three things to write down

The setting and the device

Because a number without the device it came from is worthless, including your own from six months ago.

The material and its state

Which product, and whether it felt dry, correct or damp. Moisture explains more surprises than any other variable.

What the residue looked like

Even, green in the middle, or black at the edges. It is the closest thing to a measurement available and it takes a glance.

The shortest version

Forget the number

It describes the heater rather than the material, and it does not transfer between devices or between people.

Watch two things instead

The taste, which tells you within a single draw, and the colour of the residue, which tells you at the end of the session.

Change one variable at a time

Setting, grind or packing. Changing two teaches you nothing about either, which is how most people spend months without learning their own device.

A short glossary

Conduction

Heat transferred from a hot surface directly into material in contact with it, which heats unevenly.

Convection

Heat carried into material by hot air passing through it, which heats more evenly and depends on airflow.

Sensor offset

The difference between the temperature a device displays and the temperature the material actually reaches.

Boiling point chart

A table of individual compound boiling points measured in isolation, which does not describe what happens in a mixture within plant tissue.

Working range

The span of settings that produces good results on a specific device with specific material, which is the only transferable form of this knowledge.

The five checks that apply to any product

The batch certificate

Request it with the number printed on the packaging. A general document for the product line does not cover this batch, and those differences are exactly what it should record.

Total THC

Delta-9-THC plus THCA multiplied by 0.877, because THCA becomes THC under heat and the limit applies to the sum, not to either value alone.

Price per milligram

A division, not an opinion. The only figure that makes two products comparable, whatever the format, process and pack size.

The claims

Without an authorisation number in the EU Register these are assertions, not data — and for cannabidiol that register contains no authorised entry to this day.

The seller’s details

Company name, address and contact. Without them there is also no counterparty to turn to if something turns out to be wrong.

How this connects to the rest

With the grinder

Particle size affects heating as much as the setting does, and it is the variable most often overlooked.

With storage humidity

Material in the correct range performs predictably. Damp or over-dried material does not.

With cartridges

The same sensor problem applies, with less control and generally no display at all.

With the certificate

It describes composition. Nothing about how a device delivers it appears on any document.

What this is for in practice

Ignore charts

Compound boiling points measured in isolation do not describe what happens in your device.

Ignore other people’s settings

They were learned on different hardware with different material.

Find your own range

Start low, change one variable at a time, write down what happened. A few sessions is enough.

Check the grind and the moisture first

When results change unexpectedly, those two explain it more often than the setting does.

Frequently asked questions

Why is the display not the material’s temperature? Because the sensor sits in or near the heating element, not in the material. The gap depends on the device.

How large is the difference? Variable and frequently substantial. It is a property of the design rather than a fixed offset.

Do boiling point charts work? No. They describe pure compounds in isolation. In a mixture within plant tissue, compounds leave progressively rather than at thresholds.

Can I use someone else’s settings? Not reliably. Sensor placement, heating method and airflow all differ, so the same number means different things.

What is the difference between conduction and convection? Conduction heats by contact and unevenly; convection heats by hot air passing through and more evenly. Most devices combine both.

How do I find my setting? Start low, raise one step at a time, change only one variable per session, and write down what happened.

What does running too hot look like? Harsh taste, dark brown or black material, and dense harsh vapour. The taste comes first.

What does running too cool look like? Little vapour and material still green afterwards. Damp material produces the same appearance.

Does the grind matter? As much as the setting. Particle size determines airflow and surface area, and it is the commonest overlooked variable.

Does moisture matter? Substantially. Evaporating water absorbs heat, so damp material behaves exactly like a device running cool.

What we check and what we do not

We check what can be checked from documents: official registers, declared contents, certificates of analysis, arithmetic. We test no products, rank nothing, and assert no effects.

The published charts in this area have the shape of precision without the substance of it: real numbers, measured properly, describing conditions that do not exist in any device. That combination is unusually persuasive and unusually unhelpful.

What actually transfers is a method rather than a number. Start low, change one thing at a time, watch the material and the taste, and write it down. After a few sessions you have something worth more than any chart, because it applies to the device in your hand.