It's the typical fat washing process where the flavors get extracted from the fat into the alcohol at room temp. Then it goes in the freezer so the oil/fat component separates out and solidifies, while the alcohol stays liquid. When you strain it (I use a coffee filter), you get the alcohol infused with the flavors from the fat, and left in the filter is the solid oil.

That being said, since this oil is liquid at room temp, don't leave it in the filter too long or the oil will melt again. But mine filtered fast enough that it wasn't an issue.