Making your own e-juice requires just four ingredients: a base of vegetable glycerin (VG) and propylene glycol (PG), food-grade flavoring concentrates designed for vaping, and optionally nicotine base. The process itself is straightforward, closer to following a cocktail recipe than doing chemistry. What separates a good mix from a bad one is understanding how each ingredient behaves, measuring accurately, and handling nicotine safely if you choose to use it.
The Four Core Ingredients
Every e-liquid is built from the same foundation. VG is a thick, slightly sweet liquid that produces denser vapor and a smoother inhale. PG is thinner, carries flavor more effectively, and delivers a stronger throat hit, the sensation at the back of your throat that mimics smoking. A study in Nicotine & Tobacco Research found that participants rated a 70/30 PG/VG ratio as having significantly stronger throat hit than both 50/50 and pure VG mixes.
Most DIY mixers start at a 50/50 or 70VG/30PG ratio. If you want bigger clouds and a smoother feel, lean toward more VG. If you want sharper flavor delivery and more throat sensation, increase the PG. Both are available in pharmaceutical or USP grade from DIY vaping suppliers, and that grade matters. Don’t substitute cooking-grade glycerin.
Flavoring concentrates are water-soluble, food-grade concentrates made specifically for vaping. Brands like The Flavor Apprentice, Capella, and FlavourArt are widely used in the DIY community. These are not the same as essential oils, baking extracts, or anything containing oil-based ingredients. Oil-based flavorings should never be inhaled.
Nicotine base is optional but requires careful handling. It typically comes in either a PG or VG carrier at concentrations of 48 mg/mL, 72 mg/mL, or 100 mg/mL. You dilute it down to your target strength (commonly 3, 6, or 12 mg/mL) by adding only the amount your recipe calls for. In the EU and UK, nicotine concentrations in retail e-liquid are capped at 20 mg/mL under the Tobacco Products Directive, though DIY base concentrates for mixing may be available at higher strengths depending on your jurisdiction.
Equipment You Need
The most accurate and cleanest method is mixing by weight. You’ll need a digital scale with 0.01-gram precision, which typically costs under $20. Each ingredient has a slightly different density (its specific gravity), so online calculators convert your recipe percentages into grams automatically. This eliminates the mess and imprecision of syringes.
Beyond the scale, gather:
- Empty bottles: LDPE (opaque, squeezable) works well for everyday use and is easy to dispense from. PET (clear, rigid) is better if you want to see the liquid inside. For long-term storage, glass amber bottles block light and don’t interact with flavorings.
- Nitrile gloves: Essential if you’re handling nicotine base. A study of vape shop employees found that 62% handled nicotine without gloves, which is a real risk at concentrate strengths. Nicotine absorbs through skin quickly.
- Paper towels and a clean workspace: Spills happen, especially with thin PG-based nicotine.
Mixing Step by Step
Start by entering your recipe into an e-liquid calculator. Free tools like the one at AllTheFlavors or ELR (E-Liquid Recipes) let you input your target bottle size, desired nicotine strength, PG/VG ratio, and flavor percentages. The calculator outputs exact gram weights for each ingredient.
Place your empty bottle on the scale and tare it to zero. Add your nicotine base first if you’re using it, since this is the ingredient you want to measure most carefully. Tare again. Add each flavoring concentrate one at a time, taring between each. Finally, add your PG, tare, then your VG last. VG goes last because it’s the thickest and hardest to adjust if you overshoot.
Cap the bottle and shake it vigorously for one to two minutes. That’s it. Your liquid is mixed.
How Much Flavoring to Use
Most single-flavor recipes call for concentrates at 5% to 15% of the total mix, depending on the brand and flavor. Starting at the lower end is smart because over-flavoring is one of the most common beginner mistakes. Too much concentrate can mute the flavor rather than intensify it, and some flavorings taste harsh or chemical at high percentages.
Complex recipes that blend multiple flavors typically keep the total flavoring percentage between 10% and 20%. Each individual flavor might sit at 1% to 5%. The DIY community has tested thousands of concentrates and published recommended percentages for most of them, so checking a flavor database before mixing saves a lot of wasted liquid.
Chemicals to Avoid
Not all food-grade flavorings are safe to inhale. The CDC has noted that chemicals deemed “generally recognized as safe” for eating have not been evaluated the same way for inhalation. The most well-known concern is diacetyl, a buttery flavoring chemical linked to bronchiolitis obliterans, a serious and irreversible lung condition sometimes called “popcorn lung.” Research published in Environmental Health Perspectives found diacetyl across a wide range of flavor profiles, not just butter or custard but also caramel, butterscotch, piña colada, and strawberry.
Two related chemicals, 2,3-pentanedione (a diacetyl substitute) and acetoin, carry similar concerns. Reputable concentrate manufacturers now test for these compounds and label their products as diketone-free. Stick to brands that publish testing results, and avoid any flavoring not explicitly designed for inhalation.
Steeping: Why Fresh Juice Tastes Off
Steeping is the process of letting your mixed e-liquid sit so the flavors blend and mature, similar to aging a sauce or wine. Freshly mixed juice often tastes flat, sharp, or one-dimensional. Time and occasional shaking allow the flavor molecules to bond with the VG/PG base more completely.
How long you steep depends on the flavor profile. Fruit recipes are the fastest, typically tasting good after one to three days. Some single-fruit mixes taste fine right away. Cream and dessert flavors need more time, usually one to four weeks, for the richness to develop fully. Tobacco blends are the slowest, often requiring two to four weeks or longer before they hit their stride.
During steeping, store the bottle in a cool, dark place with the cap on. Some mixers uncap the bottle briefly every few days (“breathing”), but this is mostly useful in the first day or two to let volatile alcohol notes from certain concentrates escape. Extended breathing can degrade nicotine and mute flavors.
Storing Your E-Liquid
Heat, light, and air are the three things that break down e-juice over time. Nicotine oxidizes when exposed to these elements, turning the liquid darker and developing a peppery, harsh taste. Flavors also degrade, losing their sharpness and complexity.
Keep finished bottles in a cool, dark place. A drawer, cabinet, or closet at room temperature works fine. If you’re making large batches or stockpiling nicotine base, a refrigerator or freezer extends shelf life significantly. VG-based liquids won’t freeze solid at standard freezer temperatures, though they’ll get very thick. Let them warm to room temperature before using.
Properly stored e-liquid with nicotine stays usable for roughly one to two years. Nicotine-free mixes can last even longer since there’s no nicotine to oxidize. If your liquid has changed color dramatically, smells off, or tastes peppery and harsh, it’s past its prime.
Handling Nicotine Safely
Concentrated nicotine is genuinely dangerous. At 100 mg/mL, a small spill on bare skin can cause nausea, dizziness, and elevated heart rate within minutes. Always wear nitrile gloves when handling nicotine base. Latex gloves are not adequate because nicotine can permeate them.
If nicotine concentrate contacts your skin, wash the area immediately with soap and cool water for several minutes. Don’t use hot water, which opens pores and increases absorption. Keep nicotine base locked away from children and pets. Even the finished e-liquid at 3 or 6 mg/mL is toxic if ingested in quantity by a small child.
Work in a ventilated space when handling high-concentration nicotine. Avoid touching your face, and wash your hands thoroughly even after removing gloves. These precautions sound excessive until you experience your first accidental skin exposure, which most long-time DIY mixers will tell you happens eventually.
Your First Recipe
Rather than inventing a complex blend on day one, start with a well-reviewed single-flavor recipe. A standalone strawberry or vanilla custard at the manufacturer’s recommended percentage, mixed at 70VG/30PG with your preferred nicotine strength, teaches you the entire process without the variable of balancing multiple flavors. Mix a small batch of 30 mL, steep it appropriately, and evaluate. From there, you can start experimenting with two- and three-flavor combinations, adjusting percentages by small increments (0.5% to 1% at a time) based on what your palate tells you.
The DIY e-liquid community maintains enormous recipe databases with user ratings and flavor notes. Browsing top-rated recipes and reading the notes on individual concentrates will accelerate your learning faster than any amount of random experimentation.