A burnt vape hit, often called a “dry hit,” produces a harsh, acrid taste instead of the intended flavor. This unpleasant sensation signals that the vaping device is not working correctly and that the user is inhaling more than just e-liquid vapor. Inhaling the contents of a burnt coil carries health risks because the extreme heat changes the chemical makeup of the inhaled aerosol. Understanding the mechanics of the burn and the resulting byproducts explains why this common occurrence is a genuine health concern.
The Mechanism of a Dry Hit
A dry hit occurs when the heating element activates while the wicking material is insufficiently saturated with e-liquid. The wick, often made of cotton, draws liquid from the tank to the coil’s surface for vaporization. If the liquid level is too low or the user takes too many rapid puffs, the wick dries out before new liquid can fully resaturate it.
Without the cooling effect of the e-liquid, the coil temperature spikes rapidly, exceeding normal operating ranges. This intense heat scorches the dry cotton or silica wick material. The resulting harsh taste comes from inhaling combustion products from the burned wick and thermal degradation products of the e-liquid components.
Hazardous Chemical Byproducts
When primary e-liquid components, propylene glycol (PG) and vegetable glycerin (VG), are exposed to the extreme temperatures of a dry hit, they undergo thermal decomposition. This breakdown creates toxic gaseous compounds, known as carbonyls, that are absent during normal vaporization.
One significant compound produced is formaldehyde, a known human carcinogen resulting from the high-temperature breakdown of both PG and VG. The thermal degradation of glycerin also yields acrolein, a highly irritating aldehyde. Acrolein serves as a potent warning sign that the user is inhaling hazardous material. Another aldehyde generated is acetaldehyde, classified as a probable human carcinogen.
Furthermore, the superheating of the coil itself can cause the release of metal particulates, such as nickel and chromium, into the aerosol. These particulates can then be inhaled into the lungs.
Immediate and Chronic Health Consequences
The inhalation of these chemical byproducts results in both acute and long-term health concerns. Immediately after taking a burnt hit, a user typically experiences a severe cough and intense irritation in the throat and lungs. These acute symptoms are largely attributed to acrolein, a powerful irritant that attacks the respiratory tract lining.
Repeated exposure presents a chronic risk to respiratory health. Continuous inhalation of irritating aldehydes can lead to inflammation and damage to the epithelial cells lining the airways. Dry hit aerosols increase cytotoxicity compared to normal vaping conditions. Repeated exposure to formaldehyde and other irritants may contribute to lung inflammation and potentially worsen pre-existing conditions like asthma.
Practical Steps for Prevention
Preventing a burnt hit requires proper device maintenance and careful usage habits.
Key steps for prevention include:
- Priming the coil by applying several drops of e-liquid directly to the exposed cotton until the wick is visibly saturated before the first use.
- Monitoring the e-liquid level in the tank, as the coil must never be allowed to run dry.
- Referring to the recommended wattage range printed on the coil and avoiding setting the device power too high, which causes rapid dry burn.
- Avoiding “chain vaping,” or taking frequent, rapid puffs, to give the wick sufficient time to fully re-saturate between inhalations.