Hi,

I have been trying to get as 'rustic' as possible crumb structure in
white sourdough bread for a number of years i.e. characteristic large
bubbles mixed with much smaller - without really reaching what I was
looking for. I have tried everything from strongest possible flour to
plain flour and many in between, maximised hydration, tried minimal
knead, no knead, no knock down/make up and a few others things either
by design or mistake without really getting there. So finally the only
thing left to change was my culture.

I have been using for several years a culture captured on a rural
property in Catalonia (near a village called Tivissa) next to an
outdoor oven site probably last used in the 1930s (viz. third gallery
http://www.myplot.org/oven/). For experiment of a culture change I
have brought Sourdough International's San Francisco and Italian
cultures (from island of Ischia off Naples and another) http://www.sourdo.com/.

the results of my first Ischia culture bake are certainly the most
'rustic' I have ever had (including other Sourdough International
cultures I used to have)

last three pics here
http://www.myplot.org/oven/gallery.p...neous%20baking

and this was with a dough that I had slightly let over rise on main
proof with result that final proof did not rise as much as I am used
to. The Ischia loaf was 74% hydration, a mix of an organic strong
flour 60% and 40% plain organic flour (a formula I have used also with
my other cultures - without the same results)

That different cultures might substantially contribute to different
crumb structure is not something I have heard of before. What the
mechanism might be I could speculate but won't bother just now.

here are some observations on differences between my 3 cultures that I
would be interested if others recognise

San Franisco
This was quite difficult to get going in my relatively cold house.
Initial aroma in poolish mix (110% hydration) was quite sweet, almost
sickly, reminiscent of human milk. When poolish stored in fridge a
layer of froth forms on top above poolish (not sure if this still
happening). Appears very sensitive to temperature only really being
active in a narrow band from about 25C to 30C, more or less stops dead
in terms of rising when put in fridge. At right temperature bread
rises well, better than my Tivissa culture and with a slightly greater
bubble size variation than Tivissa. However not a great amount of
'sourdough' flavour compared to Tivissa and a certain gumminess of
flavour that I don't like at all. This bread tested on a friend who is
allergic to commercial baker's yeast so certainly no contamination of
that.

Ischia
easier to get going than SF culture (though weather has got slightly
warmer) - when properly going rise very dramatic both as poolish and
as 75% hydration starter, positively explosive when peaking. Less
sensitive to heat, starter placed in fridge shortly after mixing
tripled in size over night - I am used to doubling with Tivissa
starter. Initial aromas considerably more earthy than SF or Tivissa.
No indication of hooch in stored poolish yet. Bread I have only had
for 5 hours so hard to tell final taste but distinctly 'sourdough' ish
and 'umami' ish so far. For spreading butter, or worse still honey,
have to say it has too many too big holes.

Tivissa
Generally good even taste with distinct sourdough characteristics.
Much less perceptible peak of rising than the Ischia, just plods so to
speak, but under almost any temperature, which is very useful if you
don't have central heating in winter and are happy to have long
risings. Crumb structure perfectly acceptable for most purposes.

what I am now wondering is whether it might be possible to attempt to
mix/blend, for instance Tivissa and Ischia cultures.

yours
Andy Forbes