Its based on preference.
The options are canning the butter in a pressure canner or not.
Also, this can be beneficial and safe if you follow along with the instructions.
Image by Homestead Heart via YouTube
Start the pot on a low temperature so it doesnt burn the butter.
Take a ladle and constantly stir the butter until its melted to add more butter to the pot.
Use a funnel over the mason jars when you pour the butter.
Once finished, take your vinegar and paper towel, and clean the rims of the jar.
Then, use the jar lifter and place them in the pressure canner for 70 minutes.
Overall, Ive learned a lot about how to can butter.
