I was at my moms house making my son a sandwich and she admonished me for using a knife in the jam. At first I thought she was worried about peanut allergies (non of our family have a that allergy), but then she claims that knives break up the pectin in jam and only spoons can scoop it without ruining it.

I use a knife in ours almost every day and have never had (good) jam go soupy.

I assume it’s just another bullish “tip” from social media.