The purification of tallow is an optional additional step after rendering your fat into tallow. It takes additional impurities out of the tallow making it look whiter and have less of an odor. I like to purify tallow with each of my tallow rendering batches. If you overcook a tallow batch it becomes particularly important as the smell and color will be off. I burned a batch of tallow one time and was able to get it so it was almost undetectable after I purified it 4 times. With your standard batch of tallow, it should only need one round of purification.
You can see how dark the impurities were in the burned batch even after 3 rounds of purification.
For the purification, you need to cut up the tallow into large chunks and place it back in a pan over medium to high heat. Add 5 cups of water and 1/4 cup of salt. The salt will pull out any additional impurities.
Bring it to a boil and then reduce to a simmer for 10 minutes.
Allow to cool for about 5 minutes and then strain it through a cheesecloth into a metal bowl and wait for it to solidify. (I place the cheesecloth over to the strainer to give it rigidity.)
I like using the metal bowl for 3 reasons. One, I don’t have to worry about it melting, two, I know it was purified as opposed to the rendered batches which I have in the plastic molds, and three it really centers those impurities in a circle on the bottom. Place in a cool place to solidify. I like to use the refrigerator, but since I have glass shelves I wait until it has cooled a bit before I place it on the racks.
Now that it is solid you are ready for your next step. In your sink or a large basin, dump the bowl upside down quickly. The water will be trapped under the tallow and surge out all of the sudden. If it sticks in the bowl, run a little hot water over the bottom of it. Drain all the water from around it and scrape off any impurities with a metal spoon.
If you are going to use it soon, allow it to dry, cut it to the size you want, and store it in a cool dry place like a pantry or place it in the refrigerator or the freezer.
I plan on canning mine. If you want to see how I do that, check out our post.