Jar Tek (How to Decarb Rosin)

Hash rosin can be used for a wide variety of products. If you are making edibles, vape carts or topicals you will need to decarboxylate the rosin. For edibles you will want to fully decarboxylate the rosin, while for vape carts and topicals a partial rosin decarb that preserves terpene is preferred.

This is the chemical reaction that is occurring when you decarboxylate your rosin:

Items Needed:

Start by filling your jar with hash rosin. I typically use 4oz mason jars and never decarboxylate less than 28 grams at a time. Container loss is minimized by working with larger amounts. I prefer single sourced material but you can blend different hash rosins together as well.

Remember not to overfill the jar either. During decarb rosin will raise up and foam/bubble during early phase changes. Never fill the jar past 75% capacity or you will have a sticky lid to deal with and could risk the jar exploding.

Hash rosin in mason jar
Rosin Decarb (pre oven)

Fully cured hash rosin ready to be decarbed. You can also decarb fresh press hash rosin.

Rosin Decarb (pre oven)

Set your over to the lowest setting possible. I set mine to 170F but the temperatures fluctuates in the low 200’s. Home ovens are often pretty inaccurate at low temperatures. It is not a bad idea to have a temperature probe in there so that you can track what is going on in the oven.

My target temperature for rosin decarboxylation is 220F.

Warming up oven for rosin decarb

The hash rosin will start to melt during the first phase.

Rosin Decarb in the oven

Small CO2 bubbles will begin to form and the hash rosin may foam up during this stage.

Rosin Decarb phase change
Rosin Decarb phase change

As you can see above the rosin volume has increased substantially during his phase change. This is why you don’t want to overfill the jars with hash rosin.

Rosin Decarb phase change

In the next stage the rosin will begin to darken and turn into a thick liquid with heavy bubbling. The bubbles are CO2 and are released as a byproduct of the decarboxylation process.

Rosin Decarb co2 bubbles
Rosin Decarb phase change

In the final stage the oil will being to clear up.

Rosin Decarb clear oil
Rosin Decarb final product

At this stage partial decarboxylation has been achieved. As soon as the oil looks clear like this it can be used to fill vape carts.


If you are trying to go for a full decarboxylation then keep heating until no bubbles are produced.

Do not open the jar until it has had some time to cool down and come to room temperature. Decarbed rosin should be stored in the fridge or freezer and brought back up to temperature gently before it is used in formulation.

Rosin Decarb final product

The visual change in rosin appearance after decarboxylation never ceases to amaze me, especially for such a simple process.

Happy rosin decarbing!

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