DTL vaping and MTL vaping: What are they and what do they mean?

DTL and MTL are two of the most commonly used acronyms when talking about vaping. They refer to 'Direct to Lung' and 'Mouth to Lung'.

These terms can be very confusing for new vapers (and sometimes even experienced ones too!). They can be used to refer to e-cigarette tanks, coils, airflow and e-liquids and are often combined with other descriptive words to create phrases such as “Restricted DTL” and “Tight MTL”. Sometimes even I have trouble understanding exactly what people are talking about, so I think a closer look and some explanation is needed. 

What is Mouth to Lung vaping?
'Mouth to Lung' refers to the way I inhale when vaping and it's how most of us inhaled when we smoked cigarettes. I draw the vapour into my mouth and then inhale the vapour from my mouth into my lungs. Before I took up vaping it wasn't something I'd even thought about or considered. Thinking about how you actually inhale when you've done it that way for years or often decades, can often be a bit strange. Put simply, MTL is like 'puffing' on a cigarette.

What is Direct to Lung vaping?
'Direct to Lung' is a different way of inhaling the vapour, rather than drawing the vapour into your mouth you simply inhale it directly into your lungs. As someone who's never really enjoyed this style of vaping it's not that easy to explain but it isn’t puffing on a cigarette. It's more akin to just taking a deep breath while allowing the vapour to enter your lungs directly along with the air, then breathing out as you normally would.

Why this matters!
It matters because today almost all aspects of vaping are 'designed' around one style or the other. A MTL tank will have been designed to work for people who inhale in a MTL style. A DTL tank has been designed to work for people who use a DTL style. Sticking with a vape tank as an example, there will be differences in them that make them quite different to use. A DTL tank will have very open airflow and breathing through the tank will offer almost no resistance. A MTL tank will have a much narrower air flow all the way from where the air enters the tank, to where it passes through or over the coil, right up to the mouth piece that will have a narrower bore.

If you don't have the right tank for your style of vaping then it can be like trying to knock a nail in with a sledge-hammer or trying to knock a post into the ground with a rubber mallet. You need the right tools for the job! It's almost physically impossible to DTL vape using a MTL tank and the same can be said in reverse. Most tanks will offer some adjustment on the airflow, a MTL tank may go from a 'Loose MTL' to a 'Tight MTL' and a DTL tank may go from wide open airflow to a slightly 'Restricted DTL'. But they will almost always be best for one style or the other. Tanks that attempt to do both will often end up being very limiting to both camps and will result it cries of “It just doesn't go tight enough.” Or “Even wide open it's still too restrictive.”

Which e-liquid should I used for Mouth to Lung or Direct to Lung vaping?
It's very rare that e-liquids are labelled as either MTL or DTL, but the reality, as was covered in the recent blog “What is the difference between VG and PG and which mix is right for me?”, is that most are far better for one or the other. Many DTL tanks will flood using a thinner e-liquid and many MTL coils will burn out with liquid that is too thick because it just can't wick the coil fast enough. As with many aspects of vaping these aren't hard and fast rules but considerations that will help you make the right choices. Nicotine strength should also be a taken into account, most MTL vapers use a higher level of nicotine, especially when they first switch to vaping.

Vape Coils and Power
The general consensus used to be that coils with a resistance under 1 ohm (sub-ohm) were for DTL vaping and any coil over 1 ohm was for MTL vaping. But today with many different coil designs and coil materials, along with modern adjustable power devices, this isn't anywhere as clear or simple. There are several tanks on the market that use low resistance coils at low power for MTL vaping. Thankfully many are clearly marketed as MTL or DTL, as the resistance of the coil just isn't a good indicator anymore.

Power, however, is still a good guide. Almost all MTL vape coils will be designed to work between 8-18w. There aren't many MTL vapers around who would enjoy a vape over 20w on any coil, it just doesn't work with the airflow and style of inhale. Anything over that is almost always a coil designed for DTL vaping. DTL coils typically are used around 60-80w which sounds a lot compared to MTL coils but you can't really make a direct comparison in that way. DTL coils have a lot more metal to heat up and have a lot more air passing over the coil to keep it cool. There's also more e-liquid around the coil to turn to vapour, so much more power is needed. It's nothing like running a coil designed for MTL with that amount of wattage.

It doesn't matter if you vape Mouth to Lung or Direct to Lung, neither is 'better' than the other. There is a suggestion from some, that people should start with a MTL vape and then move on to, or 'upgrade', to a DTL vape. While I would always suggest starting with a MTL e-cigarette device (for no other reason than it's closer to how most people smoke) there is no good reason to switch to DTL later unless you really want to.

There will always be people who start with a DTL vape, some people don't want the experience to be so close to smoking and so immediately feel happier with a DTL device. Whatever feels best to you, whatever keeps you from that packet of cigarettes is all that matters. However, it's really useful to know what style you vape, especially when buying new products. If it's not clear always ask “Is this product for mouth to lung?” or “Is this a direct to lung tank?” because buying something that's unsuitable for you, could set you back in your goal to be smoke-free.