Wow, where did you get starter from several hundred years ago???
I once tasted some sake that was more than 100 years old... I must confess that it tasted terrible, but it was a unique experience. ;) That was long ago, and perhaps my palate is more refined now. :)
The rye bread sourdough starter was originally made at a farm in Jutland, Denmark. I got it from a relative and have kept it goring for over 30 years now.
Every time I make rye bread I dissolve about 1/4 cup of sourdough (taken aside from previous batch) in water. I then add whole grain rye flour. 12 hours later I take about 1/4 cup of the dough and put in a jar an place in fridge. That is my starter for next time I bake. You can see how it is kept fresh. I bake every 2-5 weeks.
That is so amazing to me! I wish I had learned some of these "old technologies." Thank you for writing about this, and for explaining a bit more for me how it works. ;) :)
You are welcome. Stay tuned for full story with images and recipe.