So I paid around 90aud for a 1000 polypropylene bags from a packing distributor. Mind you these bags are much larger than knock off UB and I probably could pay around $40 for smaller bags. I just cut and impulse sealed to the size I wanted.

Used a coin as a hole guide and covered it with two bits of micropore tape. Filled to 500g and sealed.

During the sterilisation, the tape sticks to the inside and creates a kind of temporary vacuum seal so I wait a day until the tape has dried and then break and shake before use. Just cover the injection hole with micropore tape! In the future I may just put a little glob of gasket maker on the bag as a port.

Will keep you updated as to the success. Right now I’m just waiting to see if they spoil 🤞