Freeze-dried roses can be used in home decoration or simply as a means of preserving roses that hold a special memory. The process for freeze-drying roses isn't difficult, but it is a time-consuming process. For your freeze-dried roses to last, it's important to follow the proper freeze-drying process using equipment that will freeze-dry roses efficiently, giving you roses that will last long after the process is complete.
Remove the petals from the rose you want to freeze dry. You can attempt to freeze the stem of the rose as well, but the process will take longer and may produce uneven results. Working with the rose petals alone is the best method.
Place the rose or rose petals in your freeze-drying unit and set it to a temperature of -20 degrees Fahrenheit to begin the process. The freeze-drying unit vacuums the oxygen from the freeze-drying chamber and causes the rose to freeze quickly.
Return the rose petals to room temperature once the freeze-drying process has been completed. Set the freeze-dry machine to the appropriate temperature and the machine will slowly bring the rose petals to that temperature. This process takes about two weeks, and is called "sublimation." It turns the liquid in the rose petals to gaseous water vapour, allowing the finished petals to maintain their shape without wilting or discolouring.
Place the freeze-dried rose petals in a freezer bag or box and keep them in a cool, dry place for best results. The freeze-dried roses will last for several months.