You only need about 6 kernels. It's to enhance the natural flavour of it. I think she tips the jars upside down to help the hot jam create a seal in the jar lid. She doesn't sterilise them either, just makes sure that they are clean. I just work on the principle hot jam into hot jars. The parafin will stick and you don't melt it over direct heat - you need to use a double boiler. I have a small metal bowl that I use and you drain off the excess wax before washing the bowl out while it's still hot - otherwise its a huge PITA to clean.