Ideal, safe methods for thawing pork involve defrosting it in the fridge or with the aid of cold water. All meats, including pork butt, require a minimum of 24 hours of thawing per five pounds of weight in the refrigerator or 30 minutes per pound in cool water. Although the U.S. Department of Agriculture concedes that defrosting meat in the microwave is acceptable, large items such as pork butt will thaw unevenly.
Refrigerator
Place the pork butt in a baking dish lined with paper towels or on a wire rack placed on a sheet pan. Elevating the cut of meat allows air to circulate underneath and keeps it out of the liquid released while defrosting.
Place the pork on the bottom shelf of the fridge to prevent cross-contamination with other foods.
Defrost the pork 24 hours for every five pounds. Use the meat within three to five days of defrosting.
Water
Submerge the pork butt in a large plastic container, and fill the container with cold water.
Replace the water every 30 minutes.
Thaw the pork 30 minutes for every pound, and cook immediately upon thawing. Don't refreeze pork butt thawed with the cold-water method.