Sensitivity to PG
Throat irritation in new e-cigarette users
Glycerine viscosity issues
Questions are sometimes raised about PG  sensitivity, leading to discussions about a change to VG – but this brings up its own issues, particularly regarding viscosity problems in carto tank systems. Some of these topics are examined below.
This article was written specifically for the benefit of e-cigarette store owners, one of whom brought up these issues; in general, shop owners/managers are keen vapers but not technical experts. There is no comparison between the relative size of the knowledge base for ecigarette vendors and tobacconists (vendors of cigarettes and tobacco): the amount of knowledge required by an ecigarette supplier is hundreds of times greater than that for a tobacconist. An ecig vendor needs at least two years of experience to reach a basic level of competency, since they are customer-facing staff who will have two major issues to contend with:
1. A continual volume of questions about the products, and about general vaping issues (two things that are interdependent: few vaping issues can be discussed without reference to the products).
2. A significant number of new users, who deserve the best advice.
In order to assist transition from smoking to vaping, a mentor requires knowledge of the many thousands of options in order to achieve the best success rate: zero-option vaping has a success rate of as low as 10%, whereas full-option vaping may succeed in 75% of cases under optimal circumstances . As an example, there are more than 7,000 refill variants offered by just one vendor; a few of these will work and most won’t, for any smoker attempting to switch – and the optimal choices will be different for each smoker.
Perhaps at a later date there will be large chains of ecigarette stores, who will be able to run staff training courses; until then we may find a knowledge shortfall at the shop counter.
New ecig users experiencing throat irritation
First, ensure that persons who are new to ecigs do not inhale direct to the lungs, as many smokers do. Draw the vapour into the mouth – hold – inhale (if required) . Tobacco smoke contains anaesthetics designed to reduce throat and lung irritation, ecig vapour does not. Despite the fact that vapour is simply a water-based fog, inhaling anything other than pure air causes a reaction, which can be mitigated by correct technique. All cases of ‘lung irritation’ are caused by incorrect technique, since an e-cigarette is not used like a cigarette (in multiple ways).
Inhaling directly to the lungs is incorrect technique with an e-cigarette and can lead to irritation or coughing. While any/all variations of every aspect of ecig use may work for experienced users, who will certainly be able to use a direct lung inhale if they wish, beginners need correct advice in order to transition successfully.
Beginners need correct advice, and not providing it helps no one. Indeed, it would be easy to achieve extremely poor results with an ecigarette by isolating the beginner from correct advice (or even deliberately withholding it). This is clear from studies where deliberate minimising of information and product variations was employed, which generally results in success rates as low as 10% or issues such as ‘lung irritation’, neither of which have any relevance to correct use.
Sensitivity to PG
About 1 in 10 people are sensitive to PG, meaning that they suffer from upper respiratory tract irritation and/or excessive drying-out . Most will experience reducing symptoms if they persist with vaping, as they become tolerant to it. For others, the symptoms may persist, and there could be a benefit in changing to VG  or PEG-based  refills.
Sensitivity to glycerine
About 1 in 1,000 are sensitive to VG and must avoid it. However at this point we don’t know if these people are sensitive to a particular type of VG, since there are at least 5 different ways of making it (animal source, single vegetable source, mixed vegetable source , synthetic source, biodiesel byproduct, and more). If it seems worth the effort, other types could be tried, although the main problem at this time is identifying the source type. In theory a synthetic glycerine should be problem-free and this is the basis for its use in many inhalable medicines.
Another base type: PEG
PEG is a viable alternative base especially as it presents flavours better than either PG or VG. It has been extensively used in prefilled cartos for this reason, especially when supplied from the Boge-Dekang factories. However it is the most usual base type to experience contamination issues with DEG, a toxic glycol made in the same feedstock manufacturing facilities and therefore liable to cross-contamination issues. If PEG can be located in a high-quality form and efficiently tested as absolutely free from DEG, it is a good alternative base material .
The concept of VG being ‘thick’, that is to say gloopy, or more correctly too viscous, is erroneous: it means that it has not been sufficiently diluted. Glycerine must be diluted by around 20% before it becomes usable for vaping. It can be diluted by 5% to 20% with distilled water before flavourings are added. The final viscosity of a correctly-made glycerine-based refill liquid (aka ‘e-liquid’) is similar to a PG-based one – if not, it has been mixed wrongly and needs correcting. If it is too viscous then it needs further dilution.
For example a correctly-made VG liquid can certainly be used in a carto tank system. The precise viscosity of the final mix determines the precise size of the feed hole into the carto, just as it does for a PG-only or PG/VG mix. Different ‘PG’ liquids (i.e. PG/VG mixes, commonly around 80/20) may need the hole smaller or larger to avoid flooding or dry hits; this is normal (it’s why no-button pulls are sometimes needed: sucking on the driptip without operating the on/off switch, in order to pull more liquid through a system with a feed hole too small for the refill viscosity). If no-button pulls are frequently needed, the liquid viscosity is too high and it needs diluting, or the feed hole needs to be enlarged.
A suitable diluent can be anything thinner than the VG element of the liquid, and could be alcohol, PG or distilled water. There is no downside from adding 10% water, or even more: it is still effectively nebulised