How to Make Cannabutter: Step-by-Step With Dose Maths

Cannabutter is the base of most homemade edibles. Make it once and you can bake, cook or spread it on toast. Make it carelessly and you'll have no idea whether a single cookie holds 5 mg or 50.

That second problem is the one most recipes skip. This guide covers both: how to make cannabutter from flower, and how to work out what's actually in each serving before anyone eats it.

The short answer: Decarb your flower first, then simmer it gently in butter and water at 70–90°C (160–200°F) for 2 to 3 hours. Strain, chill and discard the water. To estimate strength, multiply grams of flower by its THC percentage and by 1,000 to get the maximum total milligrams, then divide by the number of servings. Assume the full number when dosing, start with a small portion, and wait at least 2 hours before having more.

What You'll Need

This batch makes about one cup of cannabutter.

Ingredients

• 3.5 g of decarbed cannabis flower (one eighth). That's deliberately modest; the dose maths below shows why.

• 1 cup (227 g) unsalted butter

• 1 cup (250 ml) water

Equipment

• A small saucepan, slow cooker or double boiler

• A kitchen thermometer

• Cheesecloth or a fine mesh strainer

• A heatproof bowl or container with a lid

• A kitchen scale

Unsalted butter gives you more control when you bake with it later. The water isn't an ingredient you keep. It stops the butter from scorching and carries away some of the grassy-tasting plant compounds, then gets thrown out.

This guide starts from flower. If you're working with distillate instead, the process is different and doesn't need decarbing or straining.

How to Make Cannabutter, Step by Step

1. Decarb the Flower

Bake coarsely broken-up flower, covered, at about 115°C (240°F) for 35 to 40 minutes until it's light golden-brown. Skipping this leaves most of the THC in its inactive form.

See our guide on how to decarb weed for times, temperatures and how to cut the smell.

2. Melt the Butter With the Water

Add the butter and water to a saucepan over low heat until the butter melts completely.

3. Add the Decarbed Flower

Stir it in so it's fully submerged.

4. Simmer Low and Slow

Keep the mixture between 70 and 90°C (160 and 200°F) for 2 to 3 hours, stirring every 20 to 30 minutes.

It should barely bubble. Never let it boil. Use a thermometer, and add a splash of water if the level drops a lot.

A slow cooker on low or a double boiler makes it easier to hold the temperature steady.

5. Strain

Set cheesecloth or a fine strainer over a heatproof bowl and pour the mixture through.

Let it drain on its own. Press gently if you like, but don't wring it hard; squeezing pushes more plant matter and bitter chlorophyll into the butter.

6. Chill

Cover the bowl and refrigerate for a few hours or overnight. The butter rises and sets in a solid layer on top of the water.

7. Separate

Lift or cut out the solid butter, pat the underside dry, and discard the water underneath.

8. Label It

Write the date and the estimated milligrams per teaspoon on the container. You'll work that number out next.

Cannabutter Dose Maths

This is the part that keeps homemade edibles from going wrong. You need three numbers: how much flower you used, its THC percentage, and how many servings you'll split the butter into.

The Formula

Grams of flower × THC% × 1,000 = maximum total mg of THC

Maximum total mg ÷ number of servings = mg per serving

Use the total THC figure from the label or lab report. It already accounts for THCA converting to THC.

Worked Example

• Flower: 3.5 g at 20% THC

• Total: 3.5 × 0.20 × 1,000 = 700 mg of THC, at most, in the whole batch

• Per teaspoon: One cup of butter is about 48 teaspoons, so 700 ÷ 48 ≈ 14.6 mg per teaspoon

Now put it in a recipe.

Say a cookie recipe uses ½ cup of butter (24 teaspoons) and makes 24 cookies. With all cannabutter, that's 24 × 14.6 ≈ 350 mg, or about 14.6 mg per cookie.

That's strong for most people, and many times the 2.5 mg Health Canada suggests as a starting dose for new users.

The easy fix is to dilute. Use ¼ cup of cannabutter and ¼ cup of regular butter, and each cookie drops to about 7.3 mg. For a 2.5 mg start, that's roughly a third of a cookie.

Quick Reference Table

Estimated maximum strength for one cup (about 48 teaspoons) of butter:

Flower used	THC %	Max total THC	Max per teaspoon
1 g	20%	200 mg	~4 mg
3.5 g	15%	525 mg	~11 mg
3.5 g	20%	700 mg	~15 mg
3.5 g	25%	875 mg	~18 mg
7 g	20%	1,400 mg	~29 mg
14 g	20%	2,800 mg	~58 mg

Why You Should Assume the Maximum

In practice, some THC is lost during decarbing and some stays in the strained plant material, so your butter will usually be weaker than the maximum.

But you can't know by how much without a lab test, and batches vary.

That's why the safe approach is to dose as if the butter is at full strength. If it turns out weaker, you can have a little more next time. If you assume it's weak and it isn't, you can't take it back.

Two more things change the maths. If you end up with less than a full cup of butter after straining, each teaspoon is stronger, so measure what you actually have.

And mix the butter thoroughly into any batter; uneven mixing is how one cookie ends up much stronger than the next.

Test One Portion and Wait Two Hours

Even with careful maths, every batch is a little different. Before you serve anything you've made, test it yourself:

1. Eat one small portion, ideally a fraction of a serving, on a day with nothing planned.

2. Wait at least 2 hours. Edibles can take 30 minutes to 2 hours to start working and around 4 hours to peak, according to Canadian public-health guidance.

3. Note how it felt and adjust the serving size for next time.

4. Don't take more because you feel nothing at the one-hour mark. That's how most bad edible experiences happen.

If you're new to edibles, start at 2.5 mg of THC or less. Don't drive, and don't mix edibles with alcohol.

Common Cannabutter Mistakes

• Skipping the decarb: Simmering butter rarely gets hot enough for long enough to fully activate THC. Decarb first.

• Letting it boil: High heat degrades THC and makes the butter taste burnt. Keep it under about 90°C.

• Grinding the flower to powder: It slips through the strainer and makes the butter gritty and green-tasting.

• Wringing out the cheesecloth: A hard squeeze adds bitterness for very little extra potency.

• Using too much flower: More flower means stronger butter, not better butter. It's much easier to dose from a mild batch.

• Not labelling it: Unlabelled cannabutter in a shared fridge is a real risk. Mark it clearly and store it out of reach of children and pets.

How to Store Cannabutter

• Fridge: In a sealed, labelled container for up to about two weeks.

• Freezer: Wrapped tightly for several months. Freezing it in measured portions, like an ice cube tray, makes dosing easier later.

• Away from light and heat: These can slowly degrade THC.

Start With Good Flower

Cannabutter is only as good as the flower that goes into it. Fresh, well-cured flower gives better flavour and a more predictable strength, and knowing the THC percentage is what makes the dose maths possible.

Every product in our flower menu lists grade and THC.

Uper Weed is an online weed dispensary Canada adults can order from in every province and territory, with discreet shipping.

Rather skip the kitchen? Our ready-made edibles list THC per piece, so there's no maths required.

Frequently Asked Questions

How much weed do I need for a cup of cannabutter?

For a manageable, beginner-friendly batch, 3.5 g of flower per cup of butter is plenty. At 20% THC, that's up to about 700 mg in the batch, or roughly 15 mg per teaspoon. Many recipes call for 7 to 14 g, which makes butter two to four times stronger.

How do I calculate the THC in my cannabutter?

Multiply grams of flower by the THC percentage and by 1,000 to get the maximum total milligrams. Divide by the number of servings.

For example, 3.5 g × 0.20 × 1,000 = 700 mg, and 700 ÷ 48 teaspoons ≈ 15 mg per teaspoon.

Do I need to decarb weed before making cannabutter?

Yes. Raw flower contains mostly THCA, which isn't intoxicating. Decarbing at about 115°C for 35 to 40 minutes converts it to THC before it goes into the butter.

What temperature should cannabutter simmer at?

Between 70 and 90°C (160 and 200°F), for 2 to 3 hours. It should barely bubble. Boiling can degrade THC and scorch the butter.

Why add water when making cannabutter?

Water keeps the butter from burning and helps carry away some of the bitter plant compounds. It separates out when the butter chills and gets thrown away.

How much cannabutter should I eat?

Start with a portion containing 2.5 mg of THC or less if you're new to edibles, then wait at least 2 hours before having more. Effects can take up to 2 hours to begin and can last for many hours.

How long does cannabutter last?

About two weeks in a sealed container in the fridge, or several months in the freezer.

Why is my cannabutter green and bitter?

Usually because the flower was ground too fine, the heat was too high, or the cheesecloth was squeezed hard. A coarser grind, lower heat and gentle straining can give a cleaner taste.

The Short Version

To make cannabutter, decarb your flower, simmer it in butter and water at 70–90°C for 2 to 3 hours, strain gently, chill and discard the water.

Then do the maths: grams × THC% × 1,000 gives the maximum milligrams in the batch, and dividing by servings gives the estimated dose.

Assume it's at full strength, dilute with regular butter if it's too strong, test one small portion, and wait at least 2 hours before having more.

Sources

• CCSA: 7 Things You Need to Know About Edible Cannabis

• CFMWS: Cannabis edibles best practice (Health Canada 2.5 mg starting dose)