Dosing Homebrew With Marijuana Tinctures | Craft Beer & Brewing

Dosing Homebrew With Marijuana Tinctures

Read on about a collaboration that combines a cold-side addition of cannabis flower with a tincture addition that allows you to customize the concentration of THC in each bottle.

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The perfect THC-infused craft beer includes our favorite dank marijuana aromas, gets us moderately high after one or two beers, and doesn’t have that chlorophyll (plant-y) flavor that dominates and overpowers the taste of a good beer. We wanted to create a beer that would accept and complement the infused THC, with significant hops to complement and harmonize with the earthier taste of marijuana and chose to start with Neil Fisher’s recipe of Weld-Werk’s Brewing Juicy Bits New England IPA because of the bright citrus hops aromas.

Andrew took the lead in selecting marijuana strains, choosing Strawberry Diesel and Lemon Jeffrey. Both strains have pungent aromas: Strawberry Diesel provides a strawberry and berry aroma; Lemon Jeffrey provides lemon and subtle grassy aromas. For those unfamiliar, cannabis is sold in a multitude of forms, from flower to concentrates, edibles, chews, candies, sprays, topical creams, even odorless tasteless powders that nearly instantly dissolve in any liquid.

“Flower” is the dried and cured plant you’re familiar with from popular culture and will be our focus. Flower is full of compounds—cannabinoids as well as terpenoids and flavonoids that give cannabis its distinct odor and flavor. The primary compounds we’re concerned with here are THCA (tetrahydrocannabinolic acid) and CBDA (cannabidiolic acid). Both compounds are cannabinoids, are unable to pass through the blood-brain barrier, and are therefore unavailable to be taken up by the body’s own endocannabinoid system because of that pesky A at the end of THC and CBD. It is THC (Δ-9-tetrahydrocannabinol) that gets you high, and CBD (cannabidiol), which is non-psychoactive, but which has a myriad of potentially beneficial properties, such as reducing anxiety and inflammation.

We won’t dwell on that here, other than to say that efficiency in your decarboxylation process is not just a matter of it being more economical, but also means you can get a relatively solid estimate on the total amount of THC in your flower, which is important for accurate THC dosing. If you know the total potential percentage of THC in your flower (this is on the label of all legally sold cannabis in Colorado) and you know the weight of your cannabis flower, as well as the relative efficiency of your decarboxylation process, then you can get a fairly accurate estimate of the total amount of THC yielded from your decarb.

For example, if your flower has the potential for 25 percent THC, you have 10 grams of flower, and your decarb process is 100 percent efficient, then you can expect the 10 grams of flower to produce 2500mg of THC. The recommended single dose for the novice ingester is 10mg of THC, which means there are 250 10mg doses in that 10 grams of flower.

No decarboxylation process is perfectly efficient, but you can get pretty close. If the idea of calculating doses causes your math phobia to rear its ugly head, you can find dosage calculators online.


Once your flower is decarboxylated, you can draw the THC out of the flower and infuse it into a medium. THC is fat soluble, so fats such as butter or vegetable oil are often used (especially in baked edibles). Ethanol is also effective and can be used to make infused liquor. A 95 percent ABV grain alcohol will hold the most THC for its given volume, but 80 proof liquors such as vodka work as well. Food-grade vegetable glycerin is our preferred method for infusing THC into beer.

For this venture, we chose a vegetable-glycerin tincture because it is water soluble and has a mildly sweet taste that would not radically change the flavor of the beer. To make our vegetable-glycerin tincture, we used a double-boil method in an oil bath. Place your decarbed flower in a heat safe container, preferably one with a high thermal mass such as a thick glass, and add your vegetable glycerin. We went with 10ml of vegetable glycerin for every gram of flower, and used 14 grams of flower so 140ml in total. In a separate larger pan, pour in enough vegetable oil to overtop the flower inside the container, but not enough to make the container float.

Heat the oil to 220°F (104°C), place the container with the flower and glycerin into the oil bath, and wait for the temperature of the glycerin to reach 180°F (82°C)—this is hot enough to allow the THC crystals to become molten and infuse the glycerin, without having to worry too much about decarbing the cannabis further and degrading the THC to CBN. At this point start your timer set for 45 minutes. Try to keep the temperature as close to 180°F (82°C) as possible. We used two meat thermometers, one in the oil bath and one in the glycerin, to check and track the temperature.

Finally, strain the glycerin and flower through a fine-mesh strainer lined with several layers of cheesecloth. Don’t be afraid to wring out the flower in the cheesecloth to extract as much glycerin tincture as possible. You will have a highly concentrated, and aromatic, tincture that you can drop into any liquid and have it dissolve quickly. Because we knew the potential percentage of THC in our flower, the volume used in our tincture (140ml), and the total weight of the flower used (14 grams), we were able to estimate that there was approximately 20mg of THC per 1ml of glycerin.

Since our goal was to create a beer with a low dose of THC, dosed at 5mg per 12-ounce bottle, that turns out to be 0.25ml of glycerin per bottle, or about one fat drop out of a medicine dropper. That means 14 grams of flower ($50 to $150 at current prices) created enough tincture to fill about 500 bottles, making it an extremely economical option for the homebrewer.


Of course, since we added the tincture at bottling, it was more than simple to up the dose—bottles with 5mg, 10mg, 20mg, 50mg, and even 100mg were made simply by increasing the volume of tincture in each bottle. We determined that the THC dosage to be consumed in each bottled beer was comparable to the dosage advertised on a serving of an edible—for example, one 10mg THC-dosed beer would have a similar effect of a 10mg edible.

For our beer, we knew the tincture would be able to provide the desired psychoactive and “body high” effects, but preserving the terpenes for the marijuana strain–specific aroma was also important so dry-hopping with freshly decarbed marijuana was vital to impart those terpene aromas from our selected strains. We tested decarbing both strains at various temperatures below the efficient conversion temperature of 220°F (104°C) and making teas until we found a temperature that preserved the aromas while still ensuring that we were killing any microbes present in the flower. Putting the ground flower in the oven for 15 minutes at 160°F (71°C) saved a good portion of the aroma, presented none of the unwanted chlorophyll flavors, and likely had minimal THCA conversion. The Strawberry Diesel maintained its aromas better and more pungently than the Lemon Jeffrey, making it a better choice for the dry-hop addition.

A quarter ounce of the decarbed Strawberry Diesel conditioned on the beer for 7 days, then we kegged the beer, used the Blichmann Quick Carb to preserve hops freshness, and bottled using the Blichmann Beer Gun. Each bottle was dosed by adding the Lemon Jeffrey tincture drops before being capped and writing the dosage amount on each bottle. The New England IPA malt and hops aroma dominated the flavor profile, but the THC flavor and aroma were noticeable and pleasant.

The dry-hopped Strawberry Diesel darkened the beer color, and the aroma could be picked up on the top. To our ultimate satisfaction, there was minimal “plant-y” flavor aftertaste, thus encouraging us to go back for another taste. The subsequent high was much more of a body high with a pleasant head high allowing the user relatively high functionality. For future batches, we might consider a lower hopped beer to allow the dry-hopped flower to make a stronger presence.