I have a quick and easy way to prepare and decarb cannabutter (or cannacoconut oil) which I consider foolproof. I just use fresh leaf/trim straight from the plant but it will work with dried as well.
1. Put your trim in a pot with a just enough water and sufficient butter for the amount of raw material. I you are using wet material you can pack it in because it will shrink considerably as it heats.
2. Bring it up to a good simmer just below the boil and hold this for about half an hour, regularly turning the material from the bottom up to the top. This exposes all the plant matter to the oil which will be predominantly at the top of the liquid.
3. Drain the contents through a fine metal strainer into another pot. boil the jug and pour this through the cooked material collected in the strainer while teasing it apart to remove any remaining oil. You can then wrap this material in a thin cloth and squeeze it out further.
4. Put the pot with the oil and water in the fridge until the butter is solid. Cut the butter off the surface, rinse the pieces in clean cold water to get the scum off the underside and then put them on paper towel and pat them dry.
5. Return the butter to a small pot or saucepan and heat gently until melted. Up the heat and monitor with a meat thermometer. keep stirring the oil because any remaining water will want to splatter, but it will dissipate quickly if you keep it moving.
6. Whilst constantly stirring, heat the oil to about 115-120 deg C (240-250 F) then let it cool to 105 C (220 F). What you will notice is that lots of fine CO2 bubbles will be released from the oil initially but these will slow down and stop within about 10 to 15 minutes. when the bubbles have stopped, take it off the heat and let it cool until you can return it to the fridge. When solid your butter is ready to use as you see fit. If storing, wrap it in plastic wrap to prevent oxidation.