Vape DIY

The electronic cigarette sector has adopted the term DIY to indicate the practice of “self-production” of vaping liquids which, if you like, is opposed to the use of so-called ready-to-use liquids.

What are the differences, advantages and disadvantages between the two methodologies in terms of e-liquid?

Ready-to-use liquids certainly enjoy the indisputable advantage of the immediacy of use and the vast choice available to the vaper; on the other hand they are (at least in theory) more expensive than the liquids obtained with DIY.

Do-it-yourself, on the other hand, enjoys an initial advantage in economic terms, but suffers a little in terms of choice and requires a lot of patience and passion.

The practice of DIY in vaping is characterized by four fundamental elements or phases:

The basis in the electronic cigarette is the fluid that is vaporized by the resistance present inside the atomizer and that generates the vapor thus simulating the effect of the smoke of the traditional cigarette, cigar or pipe.

A vape base is composed of three basic substances that are mixed together in different concentrations with the possible addition of minimum (and variable) percentages of nicotine.

The first bases for electronic cigarettes had a 50/40/10 composition, that is 50% glycol, 40% glycerol, 10% water; over time the compositions of the bases have diversified more and more, generating the most varied possible combinations.

In summary, the substances present inside a vape base are:

  • Propylene Glycol (PG);
  • Glycerol or vegetable glycerin (VG);
  • Double-distilled water (H2O);
  • Nicotine.

PROPYLENE GLYCOL (PG)

Propylene_glycol_chemical_structure 100px-PropyleneGlycol-stickAndBall

Propylene glycol or 1,2-propanediol is a chemical compound (a diol or double alcohol) having the formula C3H8O2 or HO-CH2-CHOH-CH3. It is an odorless and colorless liquid, clear and viscous with a sweetish taste, highly hygroscopic and miscible with water. (cit. Wikipedia)

PHYSICAL CHEMICAL PROPERTIES

Density: 1.036 g / cm³
Solubility in water: miscible
Boiling temperature: 188.2 ° C

The uses of propylene glycol are truly innumerable (food additive with the initials E1520, humectant in cosmetics and food, solvent for pharmaceutical preparations, etc.) but here I obviously want, inevitably, to focus on its use in the electronic cigarette sector.

In the context of use in a liquid, glycol is the best conductor of the aroma and is also the substance that, together with nicotine, returns the so-called “blow in the throat” (contraction of the larynx), a typical sensation for a smoker. Conversely, glycol can be irritating and not tolerated by some people, it is dehydrating and generates a low volume of vapor.

GLYCEROL OR VEGETABLE GLYCERIN (VG)

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Glycerol is an organic compound in whose structure there are three -OH groups (in other words it is a “triol”).
Glycerol is a component of lipids (oils and fats) and phospholipids or glycolipids, from which it is obtained by hydrolysis or transesterification. (cit. Wikipedia)

CHEMICAL PHYSICAL PROPERTIES

Density: 1.26 g / cm³
Solubility in water: complete at 19.85 ° C
Boiling temperature: 290 ° C with decomposition

It comes in the form of a transparent, viscous, colorless, odorless liquid with a slightly sweet taste. Even glycerol like glycol is used in various fields, above all the use in pharmaceuticals is the main one (as a laxative or in syrups, in toothpastes, etc.).

In e-liquids, vegetable glycerin is used which is a solution made of 95-98% from glycerol and the remaining part from water. The fundamental property of glycerin is to generate large quantities of dense vapor by simulating very well the smoke generated by analog systems. Unlike glycol, however, it tends to weaken the aromatic perception and considerably reduces the sensation of the blow in the throat.

Given its nature and its viscosity, glycerin drastically reduces the average duration of a resistance inside the atomizer (resistance fouling).

Before concluding the analysis on this liquid, one last important thing must be said about it: glycerol at high temperatures generates acrolein (an aldehyde) which is a toxic substance for the liver and irritant for the gastric mucosa. At present there is no certain information on the exact temperature that glycerin must reach to generate acroelin (the most pessimistic hypotheses speak of 150 ° C, the most optimistic of 290 ° C) and above all the temperatures that are reached are not known with certainty. in sprayers and if potentially dangerous temperatures are reached.

The only certain thing is that acroelin is, among the various components of a vape base, a substance potentially at risk, and that it is advisable for this reason not to exceed the concentration of glycerin and not to miss a minimum percentage of water inside the base itself.

BI-DISTILLED WATER OR DEMINERALIZED WATER (H2O)

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Distilled water is water almost completely free of impurities (including microorganisms, mineral salts and dissolved gases) which is obtained by distillation. The bi-distilled water undergoes a double distillation process.

It is completely free of bacteria and limestone residues. It also has a lower electrical conductivity than the starting water due to the reduction in the number of ions inside it; compared to drinking water, it has less flavor and can be described as insipid, with an indefinite, metallic or bitter taste. (cit. Wikipedia)

Its presence in liquids for electronic cigarettes is important but not fundamental: it serves to better convey the liquid inside the atomizer, spraying the resistance better and more consistently; it also reduces the temperatures of the resistances, preventing the potential risk of formation of acroelin and aldehydes in general due to the high temperatures reached by glycerol.

NICOTINE

Nicotine is a toxic plant alkaloid present in the tobacco plant.

PHYSICAL CHEMICAL PROPERTIES

Density: 1.01 g / cm³
Boiling temperature: 247 ° C

The presence of nicotine in liquids for electronic cigarettes is exclusively linked to the smoker’s so-called “hit in the throat” or the contraction of the larynx that occurs when the smoke of the traditional cigarette or the vapor of the electronic cigarette is aspirated.

Currently, ready-to-vape liquids have a nicotine rate ranging from 0 to 18 mg / ml.

For what concerns the bases on the market, it must be said that it is possible to buy bases up to a concentration of 36 mg / ml (it is however strongly not recommended to buy bases with higher concentrations).

It is important to know that nicotine is a narcotic substance that generates a strong psychic dependence (the duration of the physical addiction is relatively shorter) in its user.

The lethal dose in humans is 0.5-1.0 mg / kg.

Handle nicotine with care (latex gloves and mask) when preparing the bases for electronic cigarettes, avoiding contact!

An aroma is defined as the sensation produced by a material placed in the mouth, perceived mainly by the chemical senses of TASTE and SMELL; therefore the aroma is the result of the effect of the combination of sensory impressions of taste, smell and somato-sensorial nature in the oral cavity (touch, heat, cold, etc).

In the world of vaping, an aroma is a concentrated substance (naturally extracted or artificially created in the laboratory) dissolved in its carrier (in most cases it is propylene glycol) which must then be diluted in the base to be vaporized.

The creation of an aroma always starts from the analysis of the substance / fruit / drink / food for which the aroma is to be created; this analysis leads to the identification of its components and then to a molecular formulation that will later lead, through various synthesis and test processes, to the actual aromatic creation.

Having said that it all seems very simple but it is not as simple as it may seem; there are many aspects that an aromatiere (flavourist) must take into consideration in creating a precise aromatic profile.

Molecular complexity of the aromatic profile, cost of raw materials, solubility, viscosity, color, heat stability, ratios between the various aromatic profiles are just some of these aspects.

For example, as simple as it may seem, creating the strawberry aroma, one of the most used aromas in vaping, is anything but easy; the strawberry is made up of over 300 known molecules and an unspecified number of indefinite components.

Here below I report one of the many possible formulations of the strawberry aroma as an example:

Componente g/Kg g/Kg %
Vanillina 0,4 0,6%
g-Decalactone 2,2 3,3%
Cinnamate Methyl 3,4 5,2%
Acetic Acid 3,6 5,5%
Cis-3-Hexenol 4,0 6,1%
Caproate Ethyl 4,4 6,7%
Butyric Acid 5,4 8,2%
2-methylbutyrate Ethyl 8,0 12,1%
Furaneol 8,8 13,3%
AcetateEthyl 12,6 19,1%
Ethyl butyrate 13,2 20%
Propylene glycol 934  
TOTAL 1000  

Another very important aspect to take into consideration when creating an aroma and consequently a liquid for electronic cigarettes, is the relationship between the aromatic profiles of the ingredients to be used.

For this reason, I decided to focus this “aromas” section on aromatic combinations between the different types of aromas. The section will be updated periodically with the inclusion of new aromatic combinations.

AROMATIC COMBINATIONS

Apricot: orange, caramel, almond, honey, hazelnut, black pepper, peach, plum, vanilla, ginger.

Pineapple: caramel, coriander, tropical fruit, coconut.

Anise: citrus, cinnamon, caramel, chocolate, fig, apple, pomegranate, blueberry, coconut, peach.

Blood orange: citrus, cinnamon, chocolate, cloves, figs, almonds, honey, ginger.

Banana: coffee, cinnamon, caramel, cherry, chocolate, lemon, mango, molasses, honey, hazelnut, papaya, ginger.

Persimmon: citrus, cinnamon, apple, black pepper, pear.

Cinnamon: anise, orange, banana, cocoa, coffee, caramel, chocolate, figs, apple, melon, mint, blueberry, chilli, pear, peach, grape, vanilla.

Chestnut: coffee, caramel, chocolate, apple, pear, vanilla.

Cherry: citrus, apricot, chocolate, nectarine, black pepper, peach, plum, vanilla.

Chocolate: anise, orange, cinnamon, cloves, almond, mint, walnut, chilli, vanilla.

Coconut: citrus, pineapple, banana, caramel, chocolate, passion fruit, Brazilian nut, chilli, black pepper, vanilla.

Fig: citrus, cinnamon, almond, hazelnut, pepper, pear,

Prickly pear: citrus, tropical fruit.

Strawberry: citrus, chocolate, coriander, lime, lemon, apple, mint, black pepper, vanilla.

Kiwi: citrus, banana, cherry, berry, tropical fruit, mango, apple, coconut.

Raspberry: citrus, apricot, other berries, cinnamon, lemon, nectarine, peach, plum, vanilla, ginger.

Lime: cherry, strawberry, tropical fruit, berry, apple, papaya, plum.

Lemon: citrus fruit, apricot, cherry, prickly pear, strawberry, tropical fruit, berries, nectarine, black pepper, peach, plum.

Lychee: citrus, tropical fruit, grapes, vanilla.

Mandarin: anise, coffee, cinnamon, cherry, chocolate, figs, tropical fruit, vanilla.

Almond: apricot, orange, banana, coffee, caramel, cherry, fig, apple, honey, pear, peach, plum.

Mango: citrus, banana, cinnamon, caramel, coconut, tropical fruit, berries, apple, melon, vanilla.

Apple: maple (juice), cinnamon, caramel, chestnut, mango, pomegranate, blueberry, walnut, hazelnut, currant.

Pomegranate: citrus, tropical fruit, apple, mint.

Melon: citrus, red fruit, tropical fruit, lemon.

Peppermint: cinnamon, chocolate, tropical fruit, lemon, grapefruit.

Blueberry: citrus fruit, other berries, figs, lemon, mango, hazelnut.

Cranberry: citrus, cinnamon, chocolate, mango, apple, mint, pear.

Blackberry: citrus, apricot, other berries, cinnamon, lemon, hazelnut, black pepper, peaches, plums.

Hazelnut: citrus, apricot, banana, caramel, cherry, chocolate, fig, berries, mandarin, apple, pear, peach, plum.

Walnut: apricot, banana, cinnamon, caramel, chocolate, apple, nectarine, pear, peach, plum, rum.

Papaya: citrus, tropical fruit, lime, mango, black pepper.

Pear: citrus, cinnamon, caramel, chestnut, chocolate, almond, apple, walnut, hazelnut, vanilla, ginger.

Peach: apricot, star anise, orange, cinnamon, cherry, lime, lemon, almond, hazelnut, walnut, pistachio, maple syrup, vanilla.

Grapefruit: citrus, caramel, tropical fruit, mint, black pepper, vanilla.

Plum: citrus, cinnamon, chestnut, almonds, honey, hazelnut, black pepper, vanilla.

Rhubarb: citrus, apricot, strawberry, berries, apple, nectarine, black pepper, peach, plum, ginger.

Currants, black and red: citrus, chocolate, red fruits, lemon, vanilla.

Elderberry: apricot, fig, berries, lemon, mandarin, honey, peach, plum.

Grapes: citrus, chocolate, fig, honey, ginger.

Gooseberries: citrus fruits, white chocolate, berries, honey, hazelnut.

Food additives are defined by law at European level as “any substance not normally consumed as a food as such and not used as a typical ingredient of food, regardless of whether it has a nutritional value, which is intentionally added to food products for a technological purpose in the stages of production, transformation, preparation, treatment, packaging, transport or storage of food, it can reasonably be assumed that it becomes, itself or its derivatives, a component of such foods, directly or indirectly “(cit. Wikipedia).

Additives are classified according to their function. Three major groups of additives can be identified:

  • Additives that help preserve the freshness of food;
  • Additives that improve the sensory characteristics of food;
  • Technological additives, used to facilitate food processing but which do not have a specific function in the final product.

In the vaping sector, additives (both of natural and synthetic origin) are identified as consistency and vapor agents and have the function of giving the liquid being prepared a greater roundness of taste and a better flavor.

It is good to remember that an additive must always be used with caution and that its effectiveness is not guaranteed but that it depends on the composition of the liquid in which it will be added and the doses of use.

The additive does not make the recipe but adds something to the recipe

The following are the characteristics of the main additives used in DIY for electronic cigarettes:

ISOAMYL ACETATE

Isoamyl acetate is an organic compound of acetic acid and 3-methyl-1-butanol. It is a colorless liquid, slightly soluble in water, very soluble in most organic solvents.

Isoamyl acetate has a strong banana smell and is used to flavor foods. It is produced synthetically or naturally from the banana plant. In e-liquids it has the function of accentuating the banana flavor.

ACETHYL PIRAZINE

Acetyl pyrazine is one of the most used additives in the creation of e-liquids.

It is able to significantly change the flavor of a recipe by adding a roasted, roasted, nutty, creamy, yeasty flavor with nuances of popcorn or corn chips.

ACETHYL PYRIDINE

Acetyl Pyridine is a molecule widely used in the food industry as a flavoring substance. It tastes like popcorn and malt. It is often used in beer. Aromatically it is very similar to Trimethyl Pyrazine.

MALIC ACID

Malic acid is an additive extracted from some types of fruit such as apples, grapes and pears. In the preparation of an e-liquid it serves to increase the acidity of the preparation. Malic acid should be used in very low dosages to avoid making the e-liquid highly acidic.

BETA-DAMASCENONE

It is the molecule that is almost alone responsible for the typical rose scent and is therefore used to reproduce its typical scent. In truth, it is a little used additive in the electronic cigarette industry.

CAPSAICIN

Capsaicin is a chemical compound found in plants of the Capsicum genus (for example in hot peppers). It is one of the alkaloids responsible for the “spiciness” of chillies. Adds “hits” to e-liquids.

CIS-3-HEXENOL

Molecule present in nature in apple, potato, lemon and other fruits; it has a fresh, green, grassy and also pungent fruity flavor.

DIACETYL

Diacetyl is a natural by-product of fermentation, especially of beer. It is present in alcoholic beverages and is added to some foods to give it a buttery taste. In fact, diacetyl is a compound that gives butter its characteristic taste.

Unfortunately, diacetyl is toxic by inhalation. Prolonged exposure to diacetyl vapors causes obliterating bronchiolitis.

ETHYL BUTIRRATO

It is a molecule present in numerous fruits such as apple, banana, orange, strawberry and mango.

It has a fruity and slightly buttery flavor with notes of pineapple; it is used in fruity e-liquids to strengthen the fruity base making it softer.

ETHYL MALTOLO

It is a synthetic molecule with a sweet taste and typically of “cotton candy”. In the preparation of e-liquids it is also used as a sweetener.

ETHYL VANILLIN and / or VANILLIN

Vanillin is the molecule that gives vanilla its typical scent. It is obtained from the vanilla bean (very expensive natural vanillin) or synthetically in the laboratory (inexpensive ethyl vanillin). The desired effect of vanillin in the preparation of an e-liquid is that of binder of the various aromas present in the recipe. If the dosage is exceeded, the vanilla flavor becomes more and more present and invasive until it is strongly bitter.

EUGENOL

Eugenol is a hydroxylated aromatic compound, a guaiacol with a modified chain. This is an oily liquid, almost colorless or light yellow, which is extracted from some essential oils, especially from clove oil and cinnamon. It is slightly soluble in water and soluble in organic solvents. It has a pleasant, spicy, clove-like smell and is mainly used in tobacco e-liquids.

FURANEOL

In nature it is found in cane sugar, pineapple and other tropical fruits. It has a slightly caramelized, sweet and fruity flavor. It is used to give fruity and sweet notes to e-liquids.

GUAIACOLO

It is an organic compound of phenolic nature (pyrocatechin methyl ether), isolated from the distillation products of guaiac resin and present in high concentration in beech creosote.

It is used in an e-liquid to give a slight smoky aftertaste by increasing the density and the “tobacco” sensation in tobacco-based recipes.

LINALOL

Linanol is a monoterpene abundantly present in the essence of rosewood. It is also found free or combined in the natural essential oils of coriander, basil, lavender or bergamot. It adds a floral connotation to e-liquids.

MASSOIA LACTONE

Extracted from the bark of the Massoia tree in Indonesia, Massoia is an additive that is also widely used in the food industry to add “creaminess”. In the same way, also in e-liquids it returns a greater consistency and a creamy sensation to the recipe.

MENTHYL LACTATE (KOOLADA)

Menthyl Lactate or “Koolada” is produced from two natural ingredients, menthol and lactic acid.

It is an additive that essentially replaces menthol in the preparation of e-liquids to give freshness to the mix. It is less invasive than menthol and tends to fade over time.

METHYL CYCLOPENTENOLONE

This compound is obtained from the distillation of dry wood.

It is used in tobacco e-liquids to improve the taste, making it softer but at the same time more woody. It vaguely recalls the flavor of maple syrup.

SUCRALOSE (SWEETNER)

Sucralose or “Sweetener” is an artificial sweetener made from sucrose. It has a strong sweetening power and unlike aspartame it does not alter with heat.

TRIMETHYL PIRAZINE

Trimethyl pyrazine is a compound similar to Acetyl pyrazine but with fewer shades. It gives a typical note of dried fruit and in particular of hazelnut.

The maturation or steeping to use a term dear to the Anglo-Saxons, is the last phase of DIY, the phase of patience or rather impatience for the vaper who obviously can’t wait to be able to savor the fruit of his “work” of mixing and dosing.

But what is the maturation of an e-liquid and what is it for? To mature a preparation made of propylene glycol, vegetable glycerin, flavorings, additives and possibly nicotine serves to ensure that all the molecules of the various components combine together, creating bonds that will restore the right flavor to the eliquid. In practice, a synthesis process is carried out the faster the simpler and similar the molecular structures of the components will be (for example, vegetable glycerin has a molecular structure that slows down the maturation process of e-liquids).

So how to proceed and for how long?

Personally, I always recommend that the prepared e-liquids mature in the dark, with the bottle closed, and vigorously shaking especially in the first days of steeping.

The steeping time changes according to the percentage of glycerin used and the type of flavorings used, even if it must be said that by now most of the producers declare that their products do not need maturation or in any case minimum maturation (max 1-2 days). Development of production techniques or simply a strategic choice?

Below is a table with general guidelines on maturation times expressed in days (minimum and maximum) in the presence of a PG / VG 50/50 base:

TIPO DI AROMA TEMPO DI MATURAZIONE
Simple fruity aroma (single or double flavor) 0 – 1 days
Complex fruity aroma (more flavors, spices, etc.) 0 – 5 days
Creamy aromas 0 – 7 days
Tobacco aromas 0 -10 days
“Organic” fruity / creamy aromas 0 -10 days
“Organic” tobacco aromas 0 – 90 days