It wouldn’t be complex at all. Have a scale under the dispenser. Place your container on it. Then it tares it (discounts the weight of the container), then you just pour and it sees show much it gave and that It matches what the weight increased by. Don’t even need a person.

All sorts which are a removed to make at home because of the time and usually large batches and limited room in the fridge. I’m thinking of buying an extra freezer.

I don’t think single use plastics were bad… IF the global infra for producing actually biodegradable plastics existed and was used. But it doesn’t… yet.