If you follow vaping science at all, you've probably heard concerns about aldehydes: compounds like formaldehyde and acrolein that can form when e-liquid is overheated. The short version of what the research found is practical rather than reassuring: those compounds show up when a coil runs hotter than its wick can feed it, which is the "dry hit" every vaper recognises instantly by its burnt taste. Keep the coil wet and inside its printed wattage range and you avoid the condition the concern is about. Here's the study, then the how-to.
The study in plain English
In 2018, Dr. Konstantinos Farsalinos and colleagues measured aldehyde emissions from e-cigarettes under controlled laboratory conditions. Two findings matter for everyday use. First, the very high aldehyde readings reported in some earlier lab studies were traced to "dry puff" conditions: coils being overheated by testing machines without adequate liquid wicking, a state a human user detects immediately as an unbearable burnt taste and stops. Second, sub-ohm devices operated within the wattage range intended for the coil did not produce those dry-puff conditions. The variable that mattered was how the coil was run, not the resistance number on it.
Two honest caveats. We're a retailer, not a laboratory, so we're summarising, not endorsing. And none of this is a health or safety claim: vaping is not safe, and the study doesn't say it is. What the research gives you is a practical rule, and it's the same rule experienced vapers already follow.
Why does my vape taste burnt?
A burnt taste is the dry hit in progress. It has a short list of causes, and every one of them has a fix.
| Cause | What's happening | Fix |
|---|---|---|
| New coil not primed | Dry cotton scorched on the first fire | Drip liquid on the cotton, fill, wait 5–10 minutes. If it's already burnt, replace it |
| Wattage too high | Heat outruns the wick | Drop to the low end of the range printed on the coil |
| Chain vaping | Wick can't re-saturate between puffs | Pause 20–30 seconds between draws |
| Tank running low | Wicking ports above the liquid line | Refill before the glass is a quarter full |
| Thick liquid in a small coil | High-VG liquid can't move through tiny ports | 50/50 or 60/40 in pods and MTL coils; save high-VG for sub-ohm mesh |
| Coil worn out | Gunked or scorched cotton | Replace; typically every one to two weeks |
What this means practically
A few common-sense takeaways:
- Stay within the recommended wattage range for your coil
- Don't chain vape to the point where your coil dries out
- Replace coils when vapor taste starts to degrade; a burnt taste is a signal, not a phase to push through
- Prime new coils properly before first use
The resistance number on a coil doesn't create a dry hit on its own. Running any coil, sub-ohm or not, hotter than its wick can feed it does. If you're new to adjustable power, our VV/VW beginner's guide explains how to find the right setting, and the ohm meter guide covers what the resistance figure means.
Sub-ohm gear that tells you its range
Every sub-ohm coil we sell has its wattage range printed on it. These are the current kits, tanks and coils we'd point you at, with the ranges from their listings:
| Product | Type | Printed ranges |
|---|---|---|
| Vaporesso GTX Go 80 Pod Kit | Pen-style pod kit, 5–80 W | GTX coils from 0.15 to 0.8 Ω |
| Vaporesso GTX coils (5-pack) | Mesh coil heads | 12–20 W, 20–30 W or 32–45 W depending on resistance |
| GeekVape Z (Zeus) Sub-Ohm Tank | 5 ml leak-resistant tank | 0.2 Ω at 60–70 W, 0.4 Ω at 70–80 W |
| Eleaf Melo 4S Tank | 4 ml top-fill tank | 0.15–0.5 Ω heads, 20–70 W |
| Vaporesso iTank T 6 ml | Top-airflow tank on the GTi mesh platform | See coil |
| Geekvape Aegis Legend 5 Kit | 200 W dual-18650 mod with Z Sub-Ohm Tank 5 | Per coil |
| Vaporesso Armour Ultra Kit | 100 W built-in-battery mod | Per coil |
Browse the rest in advanced mods and tank kits, tanks and glass, and keep spares from the replacement coils collection so a burnt coil never tempts you to push through it. If you build your own, our coil building tools guide covers wicking properly.
Frequently asked questions
Why does my brand-new coil taste burnt?
It wasn't primed. Fresh cotton is bone dry; if you fire it before e-liquid has soaked through, it scorches on the first puff and never recovers. Drip liquid onto the cotton, fill the tank, and wait five to ten minutes before the first draw.
What should I do after a dry hit?
Stop, put the device down for a minute so the wick can re-saturate, and turn the wattage down a few watts before firing again. If the burnt taste stays, the cotton is scorched and the coil needs replacing.
Does high-VG e-liquid cause dry hits?
In small coils, yes. Thick 70/30 or 80/20 VG liquid wicks slowly through the tiny ports on MTL and pod coils. Use it in sub-ohm mesh coils with big wicking ports, and use 50/50 or 60/40 liquid in pods and clearomizers.
How do I know my coil's wattage range?
It's printed on the coil itself and on the box, and the product listing repeats it. Start at the bottom of that range and move up a watt or two at a time; never run above the top figure.
Not sure whether a coil is done or just underpowered? Real people, real service. Family-run since 2011.
SmokTek products are for adults 21 and over. WARNING: These products contain nicotine. Nicotine is an addictive chemical. Vaping is intended as a better smoking alternative for adult smokers. It is not a safe product, and nothing in this article is a health, safety or cessation claim. In line with the PACT Act, all shipments require an adult signature on delivery.