How to "Temper" Block Ice
For block shaved ice shavers, the temperature of your block ice can make or break your shaved ice business. Block ice that is too cold when shaved will not stick together. Ice that is too warm will create a clumpy mess. Either way, you will not get ideal results if your ice is not at the proper temperature.
To solve this problem you can "temper" or "warm up" your ice blocks in order to get the correct ice consistency. Tempering allows the ice to reach the ideal shaving temperature of 18 to 20 degrees Fahrenheit. To temper your ice, simply remove an ice block from the freezer about 10 to 15 minutes before you need it for shaving. You can place your block ice in 5-gallon buckets or restaurant trays during the tempering process. Once the ice block begins to melt on the outside surfaces, simply place the block into chest type ice coolers (48 or 60-quart coolers works best) in order to maintain the temperature. This sweating or melting of the ice blocks will be your signal that that ice has reached the tempered stage. If for some reason your block ice gets too warm, either during the tempering process or while in the coolers, the ice will become clumpy and will not hold flavor well. If this were to happen simply place the ice back into the freezer to refreeze.
One tip that will help with tempering is to adjust the temperature of your block ice storage freezer as close to 18 to 20 degrees as you can. Simply place a freezer thermometer inside your freezer to determine the temperature setting. Allow 24 hours to pass for each temperature adjustment before taking your readings.
Tempering ice will take some practice to get used to. Depending on how busy your business is, you will need to adjust how many ice blocks are tempered at one time. You will also need to get a feel for how often you need to replenish your tempered blocks. Remember, if you temper too many blocks at one time, you can always refreeze them.
For shaved ice and snow cone machines that use cube ice, tempering is not necessary.