How to make Vegemite at home
No, you need industrial machinery.

Part of the manufacturing process of producing Vegemite involves using a centrifuge to separate out the yeast cell membranes from the rest of the product. As a result, without access to such a centrifuge, it is not possible to make Vegemite.

Here is a description of the process I found through a Google search:


  Spent brewer's yeast is sieved to get rid of hop resins, and washed to remove bitter tastes. Then it is suspended in water at a temperature greater than 37 C with no nutrients: the yeast cells die, and vitamins and minerals leach out. Then the proteolytic (protein-splitting) enzymes take over, breaking the yeast proteins down into smaller water-soluble fragments, which also leach out. The yeast cell membrane is unruptured during this time, and can be removed by centrifuging. The clear light brown liquid is then concentrated under a vacuum to a thick paste (the vacuum helps preserve flavours and vitamin B1, thiamine). It is seasoned with salt, and a small proportion of celery and onion extracts to increase the palatability.