Usually, you can also buy the raw materials (seeds and seeds) from oil mills.
It is therefore best to enquire at oil mill shops that press grape seeds. There are also oil mills with online shops; we know the names of Brian Ölmühle Heilbronn and Ölmühle Garting, for example.
Furthermore, grape seeds contain little oil, so a relatively large quantity is required for oil extraction. The specialised staff at an oil mill can probably provide the best information on this.