[pete b]

I don’t bake much over the summer and let my starter expire. I usually get a new culture from a local artisan bakery but they are still closed due to covid so I want to start my own, something I haven’t done in years. I welcome any advice about this and using starters. I am a former professional chef and avid home cook and have baked literally thousands of loaves of bread but have never been completely satisfied with my sourdough game.
Mark has posted about sourdough starters in the context of insight it has given him about brewing yeast, such as retarded fermentation. I have been dying to pick his brain about sourdoughs but didn’t want to hijack the threads so I am posting here. While I welcome everyone with experience to post I am shamelessly fishing for Mark’s insights here.
I am considering using wild grapes which are ripe now as a yeast source.

[Bob357]

I use half whole wheat or rye flour and half unbleached AP and just over half the volume of filtered water as the flours combined.  Mix well and let it sit at room temperature loosely covered. Start out with 1 TBSP of each flour and 1+ TBSP water. You should have a very thick batter. After 12 hours, add the same amounts. Every 12 hours thereafter, dump half of the mix and add the same amount as what remains. You should get fermentation within a few days. At this time, I start weighing the ingredients and add equal weights of flour and water and continue dumping and feeding until the starter doubles in size between feedings. Once the starter is strong I just feed with AP flour.

[jeffy]

Here's a snippet from Saccaromyces from the yeast study on chico strains topic:

"I have learned a lot about cultures from making sourdough bread (if one has to attempted to make sourdough, it definitely appeals to the hardcore all-grain brewer).  I started my culture with 100ml of pineapple juice and 50g of organic whole wheat flour.  I stepped it up, but I was not getting the rise I wanted from the culture because it was mostly lactic and acetic bacteria. I decided to start taking two tablespoons of starter and using it to innoculate 100grams of organic whole wheat mixed into 100ml of filtered water every 12 hours.  By discarding all but two tablespoons of the culture every time I propagated it, I reduced the culture to the organisms that could reproduce significantly in 12 hours, which basically eliminated all of the weak wild yeast strains.  Now, my sourdough starter will at least double after feeding it after removing what I plan to use to make bread and placing it immediately back in the refrigerator.  It is the craziest thing to see a sourdough starter double in the refrigerator.  There are definitely cold tolerant wild strains of Saccharomyces as well as wild yeast strains from a different genus.  One of these days, I am going to plate my sourdough culture for singles."

[pete b]

I like the idea Mark presents here of selecting for fast reproduction. The problem I am having with my sourdough is that it doesn’t produce the airy crumb I am looking for, this may help.

[Saccharomyces]

After experimenting quite a bit, obtaining an airy crumb is a two-fold process.  I use a stand mixer to mix my ingredients.  I run it on low for one minute followed by running it on the next notch up for three minutes.  I then lest the dough rest for 30 minutes before doing a series of stretch and folds with a slightly wet hand to develop the gluten.  I do three sequential stretch and folds, thirty minutes apart.   I let the dough rest on the counter for another hour and half after my last stretch and fold before placing the dough in a bowl that has been lightly oiled with olive oil and then coated with rice flour, which prevents the dough from sticking when I flip it over onto parchment paper for baking in a dutch oven.  Retarding the fermentation in the one's refrigerator before placing the dough in heated dutch oven is paramount to getting good oven spring.  One's baking oven and the dutch oven has to be heated to at least 450F, 500F is better.  The dough goes into the dutch oven on parchment paper and then the lid is attached before placing it in the oven.  The beauty of using a dutch oven is that it traps steam.  The bread is baked with the lid on for 30 minutes and another 10 to 15 minutes with the lid off.

Now, seriously open crumb requires a high hydration rate.   We are talking about at least 70% hydration (i.e., 70 grams of water per 100 grams of flour). I do not like working with high hydration dough because it is very sticky, but high hydration combined with what I wrote above will result in a bread with very open crumb.  I find that a hydration rate in the 60 to 65% range to a good compromise between being able to handle the dough and get a nice crumb.

With that said, the starter I have been feeding for 9 months has now reached a point where the sourness is low, but the rise is amazing, which means that yeast are winning the battle.  I suspect that the dominant culture at this point is a strain of saccharomyces cerevisiae because the culture now smells like beer after being propagated.  There has also been a noticeable drop off in bacteria-related aromas.   In order to limit discard, I have only been keeping between 50 and 100 grams of starter.  I add new flour (70% unbleached bread flour/30% whole wheat) the day I am planning to make dough.  I only add enough to leave me with between 50 and 100 grams of starter after I harvest my crop for baking.  The starter goes immediately back in to the refrigerator until the next propagation.  I usually propagate starter at least once a week.  This culture is now so strong that adding 100 grams of mixed white/wheat flour and 100 grams of filtered water will double in two to three hours at 65F.  It behaves very much like dry activated yeast, but the flavor of the finished product is better.

By the way, I posted this image on another thread, but here is one of my early successes.  Getting an nice ear to form after scoring with a bread lame is part of getting good oven spring.

[pete b]

I use the stretch and fold method as well as the Dutch oven method when I am using my regular indoor oven. I often am using my outdoor clay oven and I believe that it is also a moist environment. It has a wooden door which I soak in water before using and I always am cooking pizzas and pita bread first and although I have to wait a couple hours for it to cool down to bread baking temperature there is really no place for moisture to go as it is completely enclosed with no flue.
I make a pretty hydrated dough too.
My sourdough comes out very good but I just don’t usually get the light crumb and big holes I like. I really  do think it’s that the starter is somehow selected for sourness rather than rising so I am going to start a new one and try to select for rise.