Let’s start by saying that the only thing you can count on about calculating dosage is that you’ll get it wrong. This by no means is intended to doubt your math skills. It is just a fact we all must embrace. Unless you have a lab and are willing to spend some serious dollars (and even then…), the best you can do is make a good approximation of the level of THC in your edibles.
Why is that? Well, determining potency simply involves too many unknowns: factors like the quality, age, potency, and type of the strain, as well as the quality of the decarboxylation process, are all critical in determining the level of high to be expected. But that’s not all—the type and quality of the carrier are also factors. Coconut oil, butter, olive oil, and alcohol absorb THC with different levels of efficacy.
So now that we’ve established that a dosage “window” for your edible is what we’re aiming for, let’s find out how to make the best estimate.
Step 1: Check the Strain Label
The strain’s potency is typically marked on the bag it came in. Make sure you note the level of THC, rather than THCa. Some producers’ labels instead indicate the THCa level, which converts to THC at a ratio of 0.88 (i.e., 100mg THCa = 88mg THC).
Step 2: Figure Out Your Strain’s THC Content in mg
A milligram is a thousandth of a gram, so each gram contains 1,000mg. If your strain’s THC level is 15 percent, each gram of flower’s THC content can be calculated as follows: 1,000mg × 15% = 150mg THC.
Step 3: Figure Out Your Recipe’s THC Content in mg
Let’s say you are using 1 ounce of marijuana (28g) to make cannabutter. Multiply that number of grams by the level of THC per gram in your strain, as follows: 28 × 150mg = 4,200mg THC.
Step 4: Figure Out Your Recipe’s THC Content Per Serving in mg
The recipe you’re making, the one that contains 4,200mg THC, will yield 3 cups of cannabutter. All that’s left to do is divide the total dosage of THC by the total number of servings. To determine the amount of THC in 1 cup of cannabutter, divide the total dosage by three: 4,200mg ÷ 3 = 1,400mg THC. If you use the 1 cup of cannabutter to make 40 cookies, then each cookie contains 1,400mg ÷ 40 = 35mg THC.
Step 5: Apply a Discount
Now we step away from the science and move on to the art. It’s impossible to know how much potency is lost during the decarboxylation and cooking processes and as a result of its combination with the carrier. But you can be certain that not all of the THC is retained during the cooking process. The best choice: Figure things out through a lot of trial and error. Eventually, after many attempts, you’ll be able to get a sense of where you’re at. I apply a conservative 20 percent discount, but that may be lower or higher in your experience by a fair margin. After you apply a 20 percent discount, your 35mg of THC per cookie translates to 35mg × 0.8 = 28mg THC.
An Important Note Regarding Cannabutter
When you use cannabutter, always slice it vertically. Each cannabinoid has a different molecular weight, and gravity plays a role here. The butter that sinks to the bottom of the batch will have slightly different qualities than that at the top.
Next – learn what is the right dose for you
