How much milk to use for each sachet of yoghurt culture, can I reculture/reuse it?

Please ensure you check your yoghurt culture sachet for dosage instructions. But each sachet generally cultures 1-2 L (1-2.1 US qt) of milk.

You can reculture a maximum of 2 further times if you'd like the culture to go further.

Note - when reculturing yoghurt batches, the purity of the strain degrades the more you reuse it.