Thawing hamburger in hot water causes the outside of the meat to quickly heat to a temperature sufficient for the growth of harmful bacteria, while the inside remains frozen. For the same reason, you should not leave meat on the countertop to thaw at room temperature. In addition, thawing in hot water may alter the texture of the hamburger, resulting in tough or chewy parts that have partially cooked in the hot water.

The fastest way to defrost hamburger is to use the microwave, although this method often results in a partially cooked, chewy exterior. Use the defrost mode if available, or set your microwave to 50 percent power to minimize this effect. If you are working with bulk ground beef rather than pre-formed hamburger patties, break up the meat as it defrosts to encourage more even thawing. You must cook your hamburger immediately after thawing in the microwave to prevent the multiplication of bacteria.

To safely defrost your hamburger and maintain an even texture throughout, submerge it in cold water, changing the water every 30 minutes to keep it cold. Place the meat in a leakproof package, or transfer it to an airtight freezer bag first. One pound of hamburger should take an hour or less to defrost using this method, while larger packages -- 3 or 4 pounds -- take several hours. Again, you must cook the meat immediately once it is thawed.

The safest way to defrost hamburger is by leaving it in the refrigerator. Not only does this limit the growth of bacteria, but it preserves the texture of the meat. Unfortunately, this method takes the longest -- at least 24 hours for even small packages of ground beef. Unlike microwave or cold-water thawing, you do not have to cook the meat immediately once it is defrosted; the hamburger can safely remain in the refrigerator for a day or two longer.