Yes, pesto is safe to freeze. Frozen pesto should be used within 3 - 4 months. Some people will argue whether to freeze pesto with or without cheese. Apparently, the quality and taste of frozen pesto with cheese will suffer and the texture might become more grainy. As my recipe doesn't have any cheese in it, I am covered here. The most popular method for freezing pesto is using a mould for making ice cubes. You fill the mould, let it freeze for a few hours. Once frozen tip all cubes into a resealable freezer bag and put back to the freezer. The other clever method of how to freeze pesto is from thekitchen.com. They spread the pesto evenly on a shallow tray lined with baking paper and let it freeze. Once frozen they cut the frozen sheet of pesto with a knife to random pieces and store in resealable plastic bag or airtight container.