Sourdough starters are *really* easy to make. My apologies to all who
have actually paid for starters, but it's like paying for chopped
onions instead of chopping them yourself.
Here's one possible way to start a sourdough culture. (1) Mix 1 1/2
cups rye flour (dark rye, if possible) with 3/4 to 1 cup water. Cover
and forget about it for a day. (2) Combine half of the previous day's
rye batter (don't worry if it doesn't smell good) with 1/2 cup rye
flour, 1/4 cup unbleached white flour and 1/2 cup water. Repeat this
process after 12 hours. (3) Combine half of the previous day's batter
with 1/2 cup unbleached white flour and about 1/2 cup water. Repeat
after 12 hours, and twice a day from then on.
By the fifth or sixth day your newly cultivated starter should be
rising nicely and the strong, foul smell should be gone. When you see
it's really nice and active, it's ready for use.
As for what factors affect starters, the most important one is
without any doubt the local flora of fungi and bacteria (in the air,
in the rye flour etc). I moved to Canada from Brazil just over three
months ago, leaving behind the sourdough starter I had been
cultivating for four years or so. I've now had a locally cultivated
starter for about two months, and it makes great bread.
They behave *completely* differently, though. For one thing, I'd
always read that when you first start the culture with rye flour, the
smell is awful. In Brazil I never got the bad smell; here in Canada
the thing stank to high heavens.
In Brazil I used to keep my culture in a *very* cold fridge (3º C
max.), and only needed to feed it about once a week (taking it out of
the fridge before using, of course). If I didn't use the culture for
two months, it would look like a soup gone bad, but the smeel wasn't
bad, and I could revive the starter by feeding it a couple of times.
Here in Canada, my starter (also kept in a cold fridge) needs feeding
more often, or it will look horrible after just a few days.
In Brazil my culture was active even at fairly low temperatures:
bread would rise, albeit very slowly, in my cold fridge. Here the
bulk fermentation of a batch of Vermont Sourdough (I should call it
BC Sourdough) at room temperature (about 21º C) will take a whole
day, so I usually put it in a really warm place, like an oven that's
been turned on for a minute or so. But it will produce wonderful
bread regardless.
My Canadian sourdough bread is a lot more sour than the same bread
when I made it in Brazil. In fact, the whole flavour is different. (I
tend to prefer the Canadian sourdough, but that may have more to do
with the great bread flour that I can buy here which cannot be found
at all in Brazil.
To sum up, I suspect that New Zealand sourdough will be completely
different from either Brazilian or Canadian sourdough. That's the
beauty of it! Keep us posted on how your sourdough turns out, and
what it tastes like.
Erik