Switching from a pre-filled vaping device to a refillable device is one of the most exciting things that you can do in your evolution as a vaper. All at once, you’ll go from a selection of just a handful of different e-liquid flavors to a selection of thousands – and that’s not all. With a refillable device, you’ll pay less to vape, and you’ll enjoy vastly superior vapor production and battery life. In order to have the best possible experience with a refillable vape pen or mod, though, you need to choose the right e-liquid – and we aren’t just talking about flavor.

E-liquid mostly contains two ingredients: vegetable glycerin (VG) and propylene glycol (PG). Adjusting the ratio of those ingredients changes the characteristics of the e-liquid and affects the type of vaping hardware that’ll give you the best experience with that e-liquid – and that’s what you’re going to learn about today.

Is a high-VG e-liquid right for you, or would you be better off with a 50/50 VG/PG ratio? Let’s learn more about how VG and PG affect vape juice.

What Is Vegetable Glycerin (VG)?

Glycerin is an ingredient that’s cheap and readily available because it’s a byproduct of the soapmaking industry. Adding lye to fat produces two products: soap and glycerin. The term “vegetable glycerin” simply means that the glycerin comes from a plant source; animal tallow is also a common ingredient in soap. Glycerin from animal sources isn’t used in e-liquid.

Vegetable glycerin most commonly comes from palm or soybean oil. Along with soapmaking, glycerin is also created during biodiesel production.

These are some of glycerin’s properties.

  • It has a sweet flavor and can be used to sweeten low-sugar or sugar-free foods.
  • It attracts moisture and can help to keep foods and other products from drying out. It also adds moisturizing properties to topical products such as soaps and lotions.
  • It thickens and enhances the mouth feel of certain beverages such as liqueurs.
  • It inhibits microbial growth and helps to keep foods, cosmetics and other products from spoiling due to fungi or bacteria. It’s also used in wound dressings and other first aid products.

Glycerin is non-toxic and is considered safe as a food ingredient.

How Does VG Affect Vape Juice?

These are the properties that VG demonstrates in an e-liquid. An e-liquid containing more VG than PG will exhibit these properties more prominently.

  • VG is thick and creates very large vapor clouds with a full and creamy mouth feel. However, the thickness of high-VG e-liquid can cause it to flow inefficiently through the tanks of small vaping devices.
  • VG has a sweet taste and can give an e-liquid a sweet flavor without the need for additional sweeteners. However, the sweetness of VG means that it may not be ideal for some flavors – such as tobacco – that aren’t supposed to be sweet.
  • VG is smooth when it’s inhaled. A high-VG e-liquid generally doesn’t produce much of a throat hit.

What Is Propylene Glycol (PG)?

Propylene glycol is a slightly viscous liquid that can be synthesized from petroleum or converted naturally from glycerin. It has many industrial applications – spraying an airplane with PG removes ice, for example – but e-liquid makers only use PG that’s rated safe for use in food.

These are some of propylene glycol’s properties.

  • It is an effective solvent and can be used in place of alcohol in products such as herbal tinctures.
  • It is a good flavor carrier and is commonly used as a base ingredient in flavor concentrates for the food – and e-liquid – industries.
  • It attracts and traps moisture and is used to help prevent products from drying out. It’s also added to hand sanitizer and eyedrops as a moisturizing agent.
  • It is an effective emulsifier and stabilizer, so it’s often used in food products such as whipped cream and ice cream, topical and cosmetic products such as deodorant, toothpaste and lotion and prescription and over-the-counter medications.
  • It vaporizes at a low temperature and is used in medical vaporizers and in smoke/fog machines.

Like VG, PG is considered safe for use as a food ingredient.

PG is a source of sensitivities and allergic reactions among a small percentage of people, with those people displaying symptoms such as contact dermatitis. If you vape and experience issues such as coughing, throat irritation, itching or rashes, you should try a 100-percent VG e-liquid and see if the symptoms subside. Because PG is so common in foods and topical products, though, it’s likely that you would already know if you were sensitive or allergic to it.

How Does PG Affect Vape Juice?

These are the properties that PG demonstrates in an e-liquid. An e-liquid containing more PG than VG will exhibit these properties more prominently.

  • PG is thin enough to flow efficiently through the wicks of small vaping devices. However, the low viscosity of PG means that a high-PG e-liquid will generate small, wispy clouds and will not have much of a mouth feel.
  • PG has almost no flavor of its own and does not enhance the sweetness of an e-liquid. However, the other flavors in a high-PG e-liquid will come through more clearly.
  • PG contributes to a more assertive – some might say “scratchy” – throat hit.

What Is the Right VG/PG Ratio for My Vaping Device?

To choose the right VG/PG ratio for your vaping hardware, simply start with this general rule: The bigger your vaping device is, the more VG your e-liquid should contain. High-VG e-liquids work best with devices that have large tanks and operate at high wattages. High-PG e-liquids work best with devices that have small tanks and operate at low wattages. Use this list of guidelines as a starting point.

  • If you have a large vape pen or box mod – and your device has a glass tank with a wide mouthpiece – you should use a high-VG e-liquid.
  • If you have a medium-sized vaping device such as a refillable pod system, try an e-liquid with a 50/50 VG/PG ratio.
  • If you have a small vaping device that’s around the same size as a cigarette or small cigar, you should use a high-PG e-liquid.