How potent are my homemade edibles?

Our advice columnist Dear Herb breaks out the pots and pans for a lesson in cooking with cannabis


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Dear Herb: I make 30 cookies out of 30 grams of bud. How do I know how potent these are without eating them? What is best method of storing the cookies? I have a licence. — Little Debbie

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Hey there, time traveller!
This article was published 07/02/2018 (1821 days ago), so information in it may no longer be current.

Dear Herb: I make 30 cookies out of 30 grams of bud. How do I know how potent these are without eating them? What is best method of storing the cookies? I have a licence. — Little Debbie

Dear Little Debbie: Lucky for you, I have a licence to do arithmetic and I’m ready to use it. (In all seriousness, though, I’d be happy to answer your question even if you weren’t a licensed user of cannabis for medical purposes.)

I’m going to answer this question in two parts: first, I’ll do a bit of back-of-the-napkin math to try and calculate the strength of your homemade cannabis cookies, then we’ll call on some experts to help check my work.

Herb answers your questions about legal consumption and growing, the law, etiquette — you name it, he'll look into it.

There’s one big variable here: how potent is the cannabis you’re using in these cookies? If you purchased the bud from a licensed producer, the packaging should list the percentage of THC by dry weight. 

For the purposes of this example, let’s assume you’re using cannabis with 20 per cent THC content. One gram of cannabis weighs 1,000 milligrams, and 20 per cent of that works out to 200 milligrams of THC by dry weight. Since you’ve proposed cooking 30 cookies with 30 grams of bud, I figure each cookie ought to contain 200 milligrams of THC.

But cooking is chemistry, and chemistry is complicated. After talking to a few knowledgeable cannabis cooks, I realized my calculation wasn’t quite accurate.

First I spoke to a woman who’s the co-director of edibles start-up Cannabiscotti, who prefers not to be named. She pointed out the conversion of THC in dried cannabis bud to THC in food isn’t as straightforward as I thought.

“If you’re not using a good process, if you’re not cleaning your bud properly — there’s a lot of things that go into getting continuous, consistent dosing,” she said.

She recommended a “fairly accurate” formula for calculating the potency of edibles that’s available on the cannabis website Leafly — but even that formula only provides an estimate of the final strength, she said.

I also spoke to Cody Lindsay, a.k.a. “The Wellness Soldier,” who explained how some of the THC contained in dried cannabis bud actually gets lost in the process of making the cannabis butter or oil that you’ll be using to bake your cookies. That process involves decarboxylating the dried cannabis bud — heating it up to turn the THCA (a chemical precursor of THC) into THC.

“When you do that, there’s a conversion process,” Lindsay said. One unit of THCA will become roughly 0.88 units of THC, he said.

On top of that, you’ll also lose some of that THC when you extract it out of your decarboxylated cannabis and into your cooking fat, said Lindsay.

“Whether it’s oil, butter, cream, honey, it’s up to you.” (Lindsay suggested you check out his cannabis cookbook for more details about creating cannabis butters and oils.)

“Under ideal conditions, you’re going to get about 60 to 70 per cent extraction into your dairy, butter, or oil,” he said.

After that process, your 30 cookies baked using 30 grams of cannabis containing 20 per cent THC would actually contain closer to 105 milligrams of THC, not the 200 milligrams I calculated, he said.

How potent is 105 milligrams of THC? It depends entirely on your individual metabolism and tolerance, but I think a cookie with 105 milligrams of THC could pack a punch.

For reference, the state of Colorado established a legal limit of 10 milligrams of THC per serving of cannabis edibles sold for recreational purposes. I’ve also heard five milligrams recommended as a starting dose for the uninitiated. If you’re not an experienced user of cannabis edibles, you might try making your cookies less potent by using less bud or simply making smaller cookies. (I offered some beginner advice on edibles dosing in a previous edition of Dear Herb.)

The upshot of all this is that calculating the THC content of your homemade edibles is an inexact science. But if you really, really want to know exactly how much THC is in the final product, my friend at Cannabiscotti had an idea.

“They do have an option, both at the bud stage, the oil stage, and the finished product stage, to send their product to a Health Canada-licensed laboratory and have it tested for THC and CBD content,” she said. “It costs approximately $250 to do that.”

As for storage tips, Lindsay said the oil in cookies like this should be good for up to six months, or up to a year frozen. Butter won’t last as long as oil, he said.

I’d add that your cannabis cookies should be clearly labelled to ensure no one mistakes them for normal cookies. If you have kids in your life, you’d be wise to keep your cookies under lock and key.

Please let me know how your cookies turn out, and happy baking.

Got a question about cannabis? Herb answers your questions about legal consumption and growing, the law, etiquette — you name it, he’ll look into it.  Email or to submit anonymously, fill out this form:    



Updated on Wednesday, February 7, 2018 4:18 PM CST: Font fixed.

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