Cannabis Seltzer Buying Guide
Discover the best cannabis seltzers from top brands and what to look for before making your purchase.
Making Cannabis Seltzer at Home
The short answer: you cannot carbonate ground flower. THC is oil soluble, so it floats on water instead of dissolving in it. A cannabis seltzer starts with a water-compatible THC base, such as a nano-emulsion, a water-soluble powder, or a small amount of high-proof tincture. That base goes into a chilled simple syrup and water blend, and the chilled liquid gets carbonated under pressure. The full process takes about two hours of active work plus chill time.
What You Need
- Decarboxylated cannabis flower or a water-soluble THC concentrate
- High-proof neutral spirit (151 proof or higher) if you make your own tincture
- Granulated sugar and water for simple syrup
- Sunflower lecithin, optional, to hold the emulsion together
- A carbonation setup: a keg with CO2, a countertop carbonator, or a carbonation cap with CO2 cartridges
- Pressure-rated glass bottles with crown caps or swing tops
- Citrus juice, fruit puree, or flavor extracts
- A syringe or milligram scale for dosing
Step-by-Step
- Spread the flower on a baking sheet and bake at 240°F (115°C) for 40 minutes to decarboxylate it.
- Cover the cooled flower with high-proof spirit in a sealed jar and let it sit for 24 to 48 hours.
- Strain the jar through a coffee filter and evaporate the alcohol down to a concentrated tincture.
- Heat 1 cup water with 1 cup sugar until the sugar dissolves, then cool the syrup completely.
- Whisk the THC base and the lecithin into the cooled syrup until the mixture looks uniform.
- Stir in your flavoring, such as 2 tbsp fresh lime juice or 3 tbsp fruit puree.
- Dilute the syrup with cold water at 1 part syrup to 5 parts water.
- Chill the mixture to 34 to 38°F, because cold liquid holds more dissolved CO2.
- Transfer the liquid to a keg or carbonation bottle and charge it with CO2 at 30 to 40 PSI.
- Shake the vessel for 30 to 45 seconds, then let it rest for 10 minutes.
- Cap the bottles immediately and return them to the refrigerator.
Dosing
Aim for 2.5 to 5 mg THC per 12 oz bottle and measure each batch with a syringe rather than a spoon. Homemade infusions vary from batch to batch, so test a small sample and label every bottle with the dose and the date. Drink effects can take 30 minutes to 2 hours to appear, so wait at least two hours before opening a second bottle.
Troubleshooting
- Flat drink: the liquid was too warm, or the cap leaked pressure.
- Oily film on the surface: the emulsion broke, so add lecithin and blend again.
- Foam overflow: too much alcohol in the mix, so keep the tincture under 1 tsp per liter.
Storage
Keep the bottles cold and drink them within 5 to 7 days. Carbonation fades over time and the emulsion can separate, so shake gently before opening. Discard any bottle that smells sour or shows mold. Never carbonate in a sealed glass bottle that is not rated for pressure.