two-preferment sourdough
Well, I tried it: two different starters, each handled to emphasize yeast activity in one, flavor production (sourness) in the second. I have three starters, all from commercial sources. Two were purchased online, the third came from a well-known bakery, with even more well-known bakers. I chose one of the online-sourced starters; it's been consistently more active (measured by proofing times, and oven-spring) than the other two, and I chose the bakery-one for its good, but not overwhelming, sourness. I maintain the first starter at 100% hydration, I keep the second one at 67% hydration. I built both formula-ready starters (450 g each) over a period of twenty-four hours tripling the seed-sarter mass 3 times, the beginning, and the end of the next two 8 hour periods, finishing with a formula-ready starter with a mass 27 time the original seed starter. I also adjust the hydration by 1/3 the difference between the seed-starters' hydration, and the target fornula-ready starters' hydrations at each build: 125%, and 60% respectively.
Bread Formula scaled to make 3, 1.5 lb. loaves.
Total starter weight: 900 g (450 each)
Total dough weight: 2250 g
Hydration: 67%
Flour: Baker's percentage:
AP flour in starters: 481g 36%
Whole Rye Flour: 225g 17%
All-purpose Flour 312g 23.5%
Bread Flour 312g 23.5%
Salt: 27g 2%
Water in starters: 419g
Water added 475g
All three loaves were baked, one at a time, under an aluminum foil cover, on a baking stone at 480°F, 10 minutes with steam. 15 additional minutes uncovered, without steam at 450°F. Reading from the top of the pile counterclockwise #1, #2 and #3; #2 was retarded for approximately 3-1/2 hour, and # 3 5 hours. 
The bread has a taste more pronounced than previous sourdoughs I've made with one or the other starters, but that could be the extra rye flour. I made a mistake; I used 10% of the dough weight, rather than ten percent of the total flour weight to caculate the desired rye content. Despite the mistake, we love the flavor. I also experienced slightly less oven spring than usual, using only starter #1.
David G
Comments
David,
Thanks for this. I've been playing with a triple-levain formula for a few weeks. As I see it each starter has different cultures, yeasts and enzyme I wanted to capture the broad flavour influences. I'm using 2 wheat starters at different hydrations (100 and 60) and a rye starter (100). I'm not happy with the results so far but it is going in the right direction. I was certain I'd been using too high a ratio of starter to final dough but I don't think it's that far off you formula. I'll have to recalculate. Your final hydration is dramatically different than mine. I'll take that into consideration on my next try.
A couple of questions if I may? Do you build the starters separately then bulk mix all ingredients? Are you doing a straight mix or are you assembling and folding? You're starting with about 16 gm of each starter?
It's good to know that someone else is attempting the same madness. ;-)
Monzy,
I had the idea for quite some time, but never acted on it. Dan DiMuzio, in reply to another post I'd made, remarked I could consider the madness some international baking teams use employing two starters. He made the comment, I think, tongue-in-cheek, but I took it seriously. Furthermore, in Hamelman's Bread there is a two preferment formula. The relatively high percentage of of starters to dough was inspired, again by Hamelman, with his Pain Rustique formula (attributed to James McGuire); more than fifty percent of the final dough weight is contributed by the poolish.
The formula is entirely mine, but influenced heavily by my cyber-mentor, D. DiMuzio: he's saved me from a lot of potential mistakes, and is a very supportive professional baker/author that contributes frequently to TFL, and, of course, Hamelman's Bread.
To answer your question: Yes, I build all my formula-ready starters seperately. Here's a link to my blog entry devoted to my approach Building a Formula-ready levain (starter)
It should answer both of your questions about starters (or way too much ;-) ). I maintain my starters in the refrigerator, and refresh them at least every two weeks with KA AP flour. When I need a rye starter, I build one, ala the method linked above) except using rye flour. I've never done it with other flour types, but it would be no different.
I have settled on the following mixing approach for all my sourdoughs. I mix all ingredients together, excluding the salt, for about two minutes in my Kitchenaid stand mixer on 1st speed. I stop when it just begins to pull together (a shaggy mess), cover it and let it rest (autolyse) for thirty minutes. I then mix it for about 3 minutes, having added the salt, on 2nd speed. I stop when I see and feel the gluten has developed reasonably well. I usually judge by the long strings of dough that cling to the sides of the bowl. I suspect I could machine-knead it longer, developing a stronger dough. I turn it out, usually directly into my oiled proofing box. I bulk proof it for 2 to 3 hours. (usually only two, but that's a function of how active the levain is.) I do a Stretch and Fold when I first turn it out, mainly to get a rectangular shape that matches the box, and again at 45 minutes, and 90 minutes. Once, I did a third S&F at 135 minutes on a dough that didn't quite "feel" right, but it probably was unnecessary.
By-the-way, when I was a child two of my heros were the court jester, and the Mad Hatter ;-)
David G
P.S. The Excel Spreadsheet, SDStarterCalculator, I built is available at:
glitzandglitterboutique.com/DavidG618/spreadsheets.html
Some cells are protected, but there is no password, so you can customize them if you wish to. The instructions say "four hours"; that's a mistake, should read "eight hours".
The loaves look great!
Mini
I've been following your's and other's advice: pick a formula and practice, practice, practice.
David G
...that doesn't mean they are eternal, Nicole.
There are two things that are the cause of most starters' demise.
1. Starters ocassionally, but rarely, get infected by bacteria that take over, or multiply enough to give bad results, from what I've heard, smells and decrease in yeast activity. There is a process called "washing" that can usually correct it. I've never had to do it, so I refer you to the search engine to find out how to wash a starter.
2. Neglect is the biggest reason starters go belly-up. That doesn't mean they are fragile. Like every other evolved creature yeast and bacteria hang on tightly. The solution is simple: maintain a workable feeding schedule. I feed mine every week to ten days, but once, during a difficult illness, they didn't get fed for seven weeks. Three days of feeding every 12 hours at room temperature, and they were as good as ever.
About my earliest posts: I became passionate about sourdough overnight, with my first reasonable success. I went through a couple of months when I baked everyday, and wrote about my findings. My analysis, looking back, may have been incomplete. That's a polite way for me to avoid saying, "Idiot, you were down-right wrong." I hope you are reading widely. Even after two years of baking sourdough--my passion is as ever, my baking schedule is much more relaxed--there is a host of TFL'ers that know and understand sourdough better than I. I have however, learned a lot.
Happy Baking!
David G