How to Make Weed Brownies: Decarb, Cannabutter, and Real Dosing Math

Most weed brownie recipes online skip the one part that matters most: how strong the brownies end up. Cannabis brownies are one of the easiest homemade edibles to get right once you know the numbers behind them. You’ll find plenty of pages with a pan of brownies and a vague line about “starting slow.” Few of them show you the math.

This guide covers the whole process: decarbing your flower, making cannabutter, baking a real batch, and working out a milligram estimate per brownie with real numbers. We’ll also cover safe storage and Canada’s dosing guidance.

 

 

What You Need Before You Start

Weed brownies come together in four stages: decarb the flower, infuse it into butter, bake the brownies, and figure out the dose. Rushing any of these steps changes your result.

Before you start, gather:

• A rimmed baking sheet and parchment paper (for decarbing)
• A saucepan or slow cooker (for cannabutter)
• Cheesecloth or a fine mesh strainer
• A 9×13 inch baking pan
• Ground cannabis flower or shake, and unsalted butter

The strength of your flower changes everything downstream. A gram of 15% THC shake and a gram of 30% THC flower infuse very differently, so know roughly what you’re working with before doing the math later on.

 

How to Decarb Weed (and Why You Have To)

Raw cannabis doesn’t get you high on its own. The THC in a fresh bud is mostly in the form of THCA, an acidic compound that your body doesn’t process the same way. Heat converts THCA into THC by knocking off a carboxyl group from the molecule. That conversion step is called decarboxylation, or decarbing for short.

If you skip decarbing and just toss ground flower into melted butter, you’ll end up with brownies that are far weaker than expected, because most of the cannabinoid content is still locked up as THCA.

Temperature and time: the commonly used home oven setting is 240F (115C) for 30 to 40 minutes. A technical review of cannabinoid conversion kinetics found that decarboxylation happens fast enough to be practical once cannabis is heated past roughly 100C, but that THC itself starts breaking down and evaporating above about 157C. A 240F (115C) oven sits comfortably in that middle zone: hot enough to convert THCA at a reasonable pace, low enough to avoid cooking off the THC you just created.

 

Steps to decarb weed

1. Preheat your oven to 240F (115C).
2. Break up your flower or shake by hand into small, even pieces. Don’t grind it to a powder, since fine dust can scorch.
3. Spread it in a single layer on a parchment lined baking sheet.
4. Bake for 30 to 40 minutes, giving the pan a gentle shake around the halfway point.
5. Let it cool completely before using it. The flower should look light brown and feel dry and a little crumbly.

A common mistake is cranking the oven higher to save time. That pushes past the point where THC starts to degrade, and you’ll lose potency instead of gaining it. Once you know how to decarb weed, the rest is straightforward.

 

How to Make Cannabutter

Cannabutter is decarbed cannabis infused into butter over low, steady heat. The fat pulls the cannabinoids out of the plant material, and you strain the solids out at the end.

 

Cannabutter ingredients

• 1 cup (2 sticks) unsalted butter
• 1 cup water
• Your decarbed cannabis (amount depends on your target dose, covered below)

 

Cannabutter steps

1. Combine the butter and water in a saucepan over low heat until the butter melts.
2. Add the decarbed cannabis and stir gently to combine.
3. Keep the mixture at a low simmer for 2 to 3 hours, stirring occasionally. It should never boil hard. A slow cooker on low works well too.
4. Line a strainer with cheesecloth and pour the mixture through it into a heatproof container, squeezing gently to get the last of the liquid out.
5. Refrigerate until the butter solidifies on top of the water, then lift it off and pat it dry.

You don’t need top shelf bud for this. Once the plant material gets strained out, what matters is total THC content, not bag appeal. This is exactly why shake makes sense for cannabutter: it’s the same cannabinoid content at a lower price per gram, since you’re straining it out anyway.

 

How Much Weed for Brownies (the Dosing Math)

This is the part most recipes leave out, and it’s the reason edibles catch people off guard. Here’s how to work out a real milligram estimate.

The formula:

Grams of flower x 1000 x THC percentage x efficiency factor = total mg THC in your batch

Then divide that number by how many brownies you cut.

A few notes on each part:

• Grams x 1000 converts your flower weight into milligrams.
• THC percentage should come from the product’s listed range. When you’re using shake instead of the top bud from the same strain, it’s reasonable to assume a lower number than the flower’s listed range, since shake often includes more leaf and smaller trim pieces.
• The efficiency factor accounts for the THC you lose during decarbing and infusing. Home methods commonly land around 70 to 80 percent efficiency, meaning 20 to 30 percent of the available THC never makes it into your butter.

 

Worked example

Let’s use Master Kush Shake at $15 for a 28 gram bag. The strain’s flower is listed in the 23 to 31 percent THC range, but shake usually tests lower than the bud it comes from, so we’ll use a conservative estimate of 15% THC for this example rather than the flower’s listed range.

Say you use 3.5 grams (an eighth of the bag) and a 75 percent efficiency factor, right in the middle of the typical 70 to 80 percent range:

3.5g x 1000 = 3,500
3,500 x 0.15 (15% THC) = 525
525 x 0.75 (efficiency factor) = 393.75mg total THC in the batch

That’s roughly 394mg of THC spread across your whole batch of cannabutter. Divide that by the number of brownies you cut to get your per-brownie estimate.

 

Dosing table (394mg total THC, 3.5g Master Kush Shake at 15% THC)

Brownies cut	mg THC per brownie (approx.)
16 large squares	24.6mg
20 squares	19.7mg
24 squares	16.4mg
32 small squares	12.3mg

This is a home estimate, not a lab result. Potency varies within a strain, and your oven and stirring add more variation. Treat these numbers as a starting point, and cut smaller pieces the first time you try a new batch.

 

The Weed Brownie Recipe

Once your cannabutter is ready, the rest is a normal brownie recipe.

 

Ingredients

• 1 cup cannabutter, melted
• 1 cup granulated sugar
• 1/2 cup brown sugar
• 3 large eggs
• 1 teaspoon vanilla extract
• 3/4 cup cocoa powder
• 3/4 cup all purpose flour
• 1/2 teaspoon salt
• 1/2 teaspoon baking powder
• 1/2 cup chocolate chips (optional)

 

Instructions

1. Preheat your oven to 350F (175C). Grease a 9×13 inch pan or line it with parchment.
2. In a large bowl, whisk the melted cannabutter with both sugars until smooth.
3. Add the eggs one at a time, whisking after each, then stir in the vanilla.
4. In a separate bowl, whisk together the cocoa powder, flour, salt, and baking powder.
5. Fold the dry ingredients into the wet mixture until just combined. Don’t overmix.
6. Stir in the chocolate chips if you’re using them.
7. Spread the batter evenly in the pan.
8. Bake for 25 to 30 minutes, until a toothpick comes out with a few moist crumbs.
9. Let the brownies cool completely in the pan before cutting. This keeps the pieces even, which matters for consistent dosing.
10. Cut into your chosen number of pieces using the dosing table above as your guide.

A ruler helps here. Even cuts keep the dose consistent from piece to piece.

 

Edible Dosage: Start Low and Wait

When I made my first batch of brownies years ago, I cut it into eight pieces, the way my mom always cut a pan of brownies. I had no idea that turned each piece into a large dose. Getting edible dosage right matters more than anything else here, and I learned that the hard way, eating a whole one and spending the evening wishing I’d cut smaller and waited longer.

Health Canada’s guidance on edible cannabis is to start with 2.5mg of THC or less if you’re new to edibles or trying a new batch. The Government of BC’s edible cannabis safe use fact sheet backs this up: effects typically show up within 30 minutes to 2 hours, and can take up to 4 hours to fully peak. That gap is why people overdo it. They don’t feel much at 30 minutes, eat more, and get hit by both doses at once.

The practical takeaway: cut your first batch small (the 32 piece row in the table above), eat one piece, and wait a full two hours before deciding whether to have more. Write down what you cut and how strong you estimated it, so your next batch is easier to plan.

If you’d rather skip the math altogether, a labelled, lab tested product takes the estimating out of the equation. Ready made edibles list exact milligrams per piece, and our gummy edibles roundup is a good place to compare options. If you’re newer to edibles generally, our guide on what to know before you eat an edible covers more ground, and our post on microdosing cannabis is worth a read if small, controlled doses are what you’re after.

 

 

Storing Weed Brownies Safely

Cannabis edibles look and smell like regular baked goods, which is exactly the problem. A few things to look out for:

• Store brownies in an airtight, clearly labelled container. Write the estimated mg per piece right on the lid.
• Keep them well out of reach of kids and pets, ideally in a cabinet they can’t get into, not just a high shelf.
• Refrigerate for up to a week, or freeze individually wrapped pieces for longer storage.
• Never leave cut brownies out on a counter or in a shared kitchen where someone could mistake them for a regular treat.

This is basic kitchen housekeeping. A labelled container and a closed cabinet solve most of the risk here.

 

Sourcing Flower for Edibles in BC

Decarbing and straining flatten out any difference in bag appeal, so cooking is one of the few times cheaper flower makes sense. Two categories worth a look:

• Shake, which is the small, loose material left after bud is trimmed and packaged. It still carries real THC content at a lower price per gram.
• Cheap ounces of flower, which run from about $40 to $80 for 28 grams with listed THC ranges, so you can still choose your potency without paying for premium bud appearance.

You need to be 19 or older to purchase or possess cannabis in BC, and federal possession limit rules set the public possession cap across Canada. If you’re mailing product in from outside the Lower Mainland, mail order shipping across Canada is available for anyone stocking up before a baking session.

 

Frequently Asked Questions

 

How long do weed brownies take to kick in?

Effects usually show up within 30 minutes to 2 hours, and it can take up to 4 hours to feel the full effect. Wait the full two hours before eating more, even if you don’t feel anything yet.

 

How much weed do you need for a batch of brownies?

It depends on the THC percentage of your flower and how many brownies you’re cutting. Use the formula grams x 1000 x THC percentage x efficiency factor, divided by servings, to get a real estimate rather than guessing.

 

What temperature do you decarb weed at?

240F (115C) for 30 to 40 minutes is the standard home oven setting. It converts THCA into THC without pushing past the temperature where THC starts to break down.

 

Can you make weed brownies without cannabutter?

Yes. Cannabis coconut oil works with the same decarb and infusion process, swapping oil for butter in equal amounts. Cannabutter is more common because of the flavour.

 

How strong are homemade weed brownies compared to store bought edibles?

Homemade brownies are much less consistent. A store bought edible lists an exact mg amount per piece because it’s lab tested. Homemade brownies only give you an estimate, even with careful math.

 

Can you use shake or trim instead of bud for cannabutter?

Yes, and it’s a practical choice. Once the plant material is strained out, what matters is total THC content, not how the bud looks. Shake is usually a lower price per gram for the same purpose.

 

How do you know if you decarbed your weed correctly?

Properly decarbed flower turns a light brown color and feels dry and slightly crumbly, not green and springy. It should also smell noticeably toasted rather than fresh.

 

How long do weed brownies last and how should you store them?

In an airtight, labelled container in the fridge, they’re good for about a week. Individually wrapped and frozen, they’ll keep for a few months.

 

What happens if you eat too much of a weed brownie?

You may feel more intense effects than expected, including anxiety, nausea, or a racing heart, and it can last several hours before passing. This is why starting small and waiting matters more with edibles than with smoking.

 

Can you use weed brownies to microdose?

Yes, if you cut them small and calculate your mg per piece carefully. Cutting a batch into 32 small squares, as shown in the dosing table above, is a reasonable way to land in a lower, more controlled range.

 

Ready to Bake?

Good weed brownies start with good flower and real math, not a guess about how strong they’ll turn out. Pick up Master Kush shake or another shake option for your next batch, or browse the full shop if you’d rather compare flower, edibles, and everything in between before you start cooking.