Vaping involves heating a liquid solution to create an aerosol, which is then inhaled. This process can be executed using distinct inhalation techniques that alter the user experience. For those transitioning from traditional smoking, understanding these styles is paramount. The two most common techniques are Mouth-to-Lung (MTL) and Restricted Direct-to-Lung (RDL). This article clarifies the physical process, resulting sensation, and hardware requirements for each method.
Understanding Mouth-to-Lung Vaping
Mouth-to-Lung (MTL) vaping closely mirrors the action of drawing on a traditional cigarette. The technique involves drawing the vapor first into the mouth cavity, holding it momentarily, and then pulling it into the lungs with a secondary, deeper breath. This two-step process allows flavor compounds to linger on the palate before final inhalation.
This style is favored by former smokers because it delivers a higher perceived “throat hit,” caused by nicotine and propylene glycol (PG) irritation. The tighter draw concentrates the vapor, intensifying this feeling. Since the vapor is concentrated and not diluted by excessive airflow, users can achieve satisfaction with a lower overall volume of inhaled aerosol.
MTL produces significantly smaller, more discreet clouds due to the lower volume of air and vapor inhaled per puff. This discretion makes the style popular in settings where large vapor clouds might be inappropriate. The low power requirements also mean that device batteries last considerably longer between charges compared to high-power styles.
Flavor clarity is exceptionally high because the vapor is dense and low airflow does not dilute the taste molecules. The mouth acts as a holding chamber, allowing the vapor to cool slightly before reaching the lungs. This results in a more comfortable and less intense inhalation experience.
Understanding Restricted Direct-to-Lung Vaping
Restricted Direct-to-Lung (RDL) vaping is a hybrid technique between the tight draw of MTL and the wide-open inhale of standard Direct-to-Lung (DTL) styles. The RDL method involves a single, continuous, and quick breath that draws the vapor straight into the lungs. Unlike DTL, the airflow is intentionally reduced, creating a noticeable resistance during the inhale that prevents an overly airy draw.
This restriction defines the RDL experience, offering a middle ground for users who find MTL too tight or DTL too airy. The reduced airflow concentrates the vapor more than DTL, resulting in better flavor fidelity. This style still allows for a much larger volume of vapor production than MTL, with an inhale that is faster and smoother.
RDL is popular for users seeking a balance between strong flavor and moderate vapor clouds. The throat hit is present but smoother and less concentrated than MTL, due to the increased volume of air mixing with the vapor. This style requires a slightly deeper lung capacity to handle the increased volume of aerosol.
The technique necessitates a medium level of power and coil performance to rapidly vaporize the larger quantity of e-liquid. The quick, direct path to the lungs means the vapor is often warmer than an MTL puff, which enhances flavor delivery. RDL serves as a transitional style for users looking to increase vapor output.
Essential Hardware Differences
Achieving the specific sensations of MTL and RDL depends entirely on selecting the appropriate hardware, particularly the coil resistance and airflow design. The MTL style requires coils with a high electrical resistance, typically 1.0 ohm (\(\Omega\)) and higher. These coils operate most efficiently at very low wattages, usually below 20 watts, resulting in the tight, cool, and discreet vapor characteristic of the style.
MTL atomizers feature tiny, narrow air intake holes that severely restrict airflow over the coil, forcing a slow, tight draw. E-liquids used in MTL devices generally contain a higher concentration of Propylene Glycol (PG) relative to Vegetable Glycerin (VG), often a 50/50 ratio. This ratio enhances the throat hit and flavor delivery. Nicotine strengths are usually higher, sometimes utilizing nicotine salts for smoother, faster absorption.
RDL setups utilize medium-resistance coils, generally between 0.5 ohm and 0.8 ohm, requiring a moderate power output typically between 20 and 50 watts. The coils are physically larger to handle the increased heat and e-liquid flow necessary for moderate vapor production. Airflow on RDL tanks is designed with wider intake slots than MTL, but they remain adjustable to allow the user to dial in the desired level of restriction. RDL e-liquids feature a more balanced VG/PG ratio, such as 60/40 or 70/30, to produce slightly larger clouds while maintaining good flavor.
How to Choose the Right Vaping Style
The decision between MTL and RDL comes down to the user’s preferences and primary motivation for vaping. If the goal is to replicate the physical sensation of smoking, including the strong throat hit and two-step inhalation, MTL is the most suitable choice. MTL is also preferred by those who require higher nicotine concentration and value discretion due to minimal vapor production.
Users looking for a more noticeable vapor cloud and a smoother inhale should consider the Restricted Direct-to-Lung style. RDL is an excellent option for intermediate users who desire more vapor volume without committing to the airy, high-power requirements of a full DTL setup. Choosing RDL provides a versatile balance between flavor intensity and vapor output.