No! You can use a balloon whisk if you do not have an electric mixer. Before whisking, I recommend to use a metal bowl and to put the bowl and whisk in the freezer for 15 minutes before you begin to make the cream. A cold bowl and utensils will help keep the heavy cream cold and allow it to aerate and form soft peaks quicker than if you did not chill it. Whisking by hand should take about 4-5 minutes.