Here is an easy way to convert your sourdough starter to an einkorn sourdough starter. You might want to have two starters, one for einkorn and one for regular sourdough and you can always dehydrate
them so you'll always have more starter.
You can use Einkorn All-Purpose Flour
or Einkorn Whole Wheat Flour
to make an einkorn sourdough starter and for more information see the *note below.