Subohming is a little different to the vaping people generally do when they first take it up. Most people start off with a small tank and a fixed power device and use liquids that are normally sold in 10ml bottles containing varying levels of nicotine. These devices are used in the same way as a cigarette where the vapour is drawn into the mouth and then inhaled. Sub-ohm vaping requires a larger tank and therefore more power. The coils in a subohm tank are larger and produce more vapour than their smaller counterparts and the vapour is inhaled directly into the lungs.
So why do people move onto a subohm device? Well more vapour means more flavour. Some people are quite happy to continue with the device (or one like it) that they bought and used originally but some want to experience the vastly improved flavour that subohming provides. Another advantage is that with a variable power device you can fine tune it to your own preferences. You can turn it up to provide a warmer vape that produces more vapour or turn it down so that it produces less vapour. Subohm liquids are sold in quantities of more than 10ml and have no nicotine in them. This is because article 20 of the Tobacco Products Directive states that nicotine e-liquids must be no larger than 10ml, so eliquid that comes in larger quantities than this must not contain nicotine. However, it can be added after purchase by the user. Most subohmers use liquids to which they then add 3mg of nicotine. It doesn't sound like much but, because they are inhaling more vapour each time, it is usually sufficient.
Subohm liquids are usually thicker than the liquids used in non subohm tanks. This is due to the bigger coils and extra power which is capable of vapourising it much more easily. Liquids for vaping are made up of two main ingredients; Propylene Glycol (PG), and Vegetable Glycerin (VG). It's the PG that holds the flavour and the VG that produces the vapour. Most subohm liquids are 70% VG and 30% PG although other ratios are used and non subohm liquids are 50/50 which is easier to vapourise with the smaller coils.
I have been told by some people that they have been put off from subohming because they don't want to be producing huge clouds of vapour but it is possible to subohm without producing a massive amount of vapour. Obviously some vapour is required but as I said previously you can minimise vapour production by using less power, less airflow and coils with a higher resistance.
If you wanted to try subohming for yourself most vape shops are set up so you can give it a go without committing to buying anything. I bet anyone who has never tried it before will be amazed at the amount of flavour that it gives you compared to the non subohm kits. Go along and try it. You have nothing to lose and it may just change the way you vape forever!