How Strong Is My Cannabutter? Estimating Potency at Home

How Strong Is My Cannabutter? Estimating Potency at Home

You made a batch of cannabutter, it smells right, it looks right — and now comes the question every home edible maker asks: how strong is this stuff, actually? Eating a mystery-potency brownie is how good evenings go sideways, so before you bake anything, let's put a number on your butter.

The honest answer up front: without lab equipment you can't measure cannabutter potency exactly. But you can estimate it within a useful range using math, and then verify it with a structured taste test. Between those two, you'll know your butter well enough to dose confidently. Here's how the Fellowship does it.

Why You Can't Just Taste-Test a Spoonful

THC has no flavor signature that tracks with strength, and edibles take 45 minutes to 2 hours to kick in. By the time an unmeasured taste test reports back, you've learned that some unknown amount of butter produced some effect — which tells you almost nothing you can scale. Worse, a strong batch punishes the experiment.

Estimation first, structured testing second. In that order.

The Cannabutter Potency Formula

Your butter's strength is set by four numbers you already know:

(grams of cannabis × THC% ÷ 100 × 1000 × decarb efficiency) ÷ teaspoons of butter = mg THC per teaspoon

Worked example — the most common home batch:

• 7 grams of flower at 20% THC, decarbed in the oven (~90% efficiency), infused into 1 cup of butter (48 teaspoons)
• Total THC: 7 × 0.20 × 1000 = 1,400mg
• After decarb losses: 1,400 × 0.90 = 1,260mg
• Per teaspoon: 1,260 ÷ 48 = ~26mg THC per teaspoon

Rather than run those numbers by hand every batch, use our free cannabutter calculator — it handles any ratio, any decarb method, and converts between cups, tablespoons, and teaspoons for you.

The Four Things That Change Your Real-World Potency

The formula gives you a ceiling. Real batches come in somewhat under it, and these are the reasons:

1. Your decarb quality

Decarboxylation — activating THC with heat before infusing — is where most potency is won or lost. Under-decarbed flower leaves THCA unconverted; overheated flower degrades THC into sleepy CBN. Oven at 240°F for 40 minutes is the standard; see our decarboxylation guide for times and temps by method. If you skipped decarb entirely, your butter is running at a small fraction of its potential — that's the single most common reason a batch feels weak.

2. The THC% you plugged in

Dispensary labels are reasonably reliable; estimates for homegrown or unlabeled flower are guesses. If you don't know the percentage, assume 15–20% for modern flower and treat your first servings cautiously.

3. Infusion and straining losses

Some THC stays behind in the plant material when you strain, especially if you let gravity do the work (which you should — squeezing the cheesecloth pushes bitter plant matter into your butter). Budget for roughly 10–25% loss here on top of decarb efficiency.

4. Water separation

If you water-cured your butter (simmering with water, then chilling to separate), a little infused butter is lost with the discarded water. Minor, but it adds up with the other losses.

Practical rule: treat your calculated number as the maximum, and assume your real potency is 75–90% of it. If the math says 26mg per teaspoon, dose as if a teaspoon might carry about 20–26mg.

The Structured Taste Test: Calibrating Your Batch

Once you have the estimate, verify it with a single standardized dose:

1. Pick a small test dose. Measure out butter containing an estimated 5mg THC — with 26mg/tsp butter, that's about 1/5 teaspoon. Spread it on a cracker or toast.
2. Eat it on a normal stomach (not empty, not stuffed) and note the time.
3. Wait a full 2 hours. No topping up. Onset commonly runs 45–120 minutes.
4. Rate the effect. Nothing? Your butter is likely weaker than calculated — adjust your working number down and repeat tomorrow with a slightly larger dose. Comfortable and noticeable? Your estimate is close. Stronger than expected from 5mg? Your working number is low — scale it up and re-dose future servings accordingly.

One calibrated data point turns your estimate into a working potency number you can bake with. Log it — future-you will thank present-you.

When You Want a Real Measurement

If you make edibles regularly or share them, a home potency tester like the tCheck measures infused butter and oil directly for a few hundred dollars, and some testing labs accept homemade infusion samples. For most home cooks, though, formula + calibration test is accurate enough to dose safely and repeatably.

Label It While You Know It

Whatever number you land on, write it on the container: date, strain, and mg per teaspoon. Cannabutter keeps 2 weeks refrigerated and 6 months frozen, and no one remembers March's batch details in June. Our edibles storage guide covers keeping potency stable over time.

From Butter Potency to Recipe Dosing

Knowing mg-per-teaspoon is step one; step two is portioning it across a recipe. If your butter is 26mg/tsp and a cookie recipe uses 8 tablespoons (24 teaspoons) of it across 24 cookies, each cookie lands at ~26mg — a heavy dose. Cut the infused butter with regular butter to hit your target. Our cannabis dosage calculator does this two-step math for any recipe, and if you're starting from scratch, the complete cannabutter guide walks the whole process from decarb to finished butter.

FAQ

How do I know if my cannabutter is strong enough?

Estimate potency with the formula (grams × THC% × 1000 × decarb efficiency ÷ teaspoons), then verify with a single measured ~5mg test dose and a 2-hour wait. If the test dose does nothing, revise your estimate downward and retest with a modestly larger dose the next day.

How strong is cannabutter made with 7 grams?

Seven grams of 20% THC flower oven-decarbed into one cup of butter yields roughly 26mg THC per teaspoon before infusion losses — realistically 20–26mg. Stronger flower, tighter straining, or less butter raises that; skipped decarb craters it.

Why is my cannabutter weak?

The usual suspects, in order: no decarb or under-decarb, overestimated THC%, too much butter for the flower used, or heavy straining losses. Decarb issues dominate — fix that first before blaming the flower.

Can you measure THC in cannabutter at home?

Not exactly without a device, but you can bracket it: calculate the theoretical maximum, assume 75–90% of it, then calibrate with a measured test dose. Home potency testers like the tCheck give a real measurement if you want one.

How much cannabutter equals one dose?

It depends entirely on your batch. At ~25mg/tsp, a beginner 5mg dose is about 1/5 teaspoon; a standard 10mg dose is a bit under half a teaspoon. This is why potency-per-teaspoon is the number worth knowing — and writing on the jar.