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Sourdough Rye Question

silverthyme's picture
silverthyme

Sourdough Rye Question

I have been making a "sourdough" rye for over 30 years - although I suppose technically it isn't sourdough as I add yeast... I love the recipe - it gives me a tangy sour chewy loaf like a NY rye, but I would like to make a similar loaf using no added yeast ...

This is the recipe I've been using : http://silverthyme.blogspot.com/search?q=sourdough. I let the starter sit in the fridge until it reaches the state when most bakers would  pour off half and feed the starter, But instead I use about a cup and a half of this unfed starter (which has a tangy sour smell) and then feed whatever remains.

When I try to make bread without adding yeast and use a starter made by equal weight rather than volume as I have been doing - and using a newly fed starter - it's not as "tangy" or sour and the starter smells like yeast rather than the sharp smell my old starter has  ...

I guess what I am asking is - how can I get the same level of sour/tangy without using added yeast?

 

 

richkaimd's picture
richkaimd

The sour taste in a sourdough starter is not what makes a dough sour.  You simply don't impart enough of your starter's sour chemicals into your dough to do that.  The function of your starter is to act as a carrier of the leavening microbes into your dough.  Your starter, in that sense, is your yeast.  You don't need to add dry yeast at all if your starter is alive.

So, that said, where does the sour flavor come from in a sourdough bread?  It comes from the same place that your starter gets it.  It comes from allowing your dough to rest long enough for the fermentation product that is sour to develop.  I do this by slowing down the yeast action with refrigeration.  For example, I allow my bagels to sour by leaving them in the fridge for at least 18 hours before I boil then bake them.  At the other end of the spectrum, when you don't want any sour flavor, yet want to use your sour dough starter as your leavening agent, simply speed up your first rise by placing your dough in a warm environment.  

With these facts known, you can understand why a dough with any yeast for leavening, be it a sourdough starter or dry active yeast, can either be sour or not, depending on temperature (and therefore duration) of its bulk rise.

 

 

 

silverthyme's picture
silverthyme

So if I understand it - what I've been doing is slowing down my starter with refrigeration long enough to get it really sour and then using  about 1.5- 2 cups to make my dough more as flavoring than leavening and using the dry active yeast leaven it.

dabrownman's picture
dabrownman

one is that it carries the yeast which produce CO2 and ethanol as they reproduce which leavens the bread.  The other function is that LAB live in symbiosis with the yeast in the SD culture and they produce acids as they reproduce creating the sour taste.  A normal SD culture will have around 100 LAB to each yeast in the culture and at all temperatures, LAB will outproduce yeast- by a little at room temperatures 64-78 F and by a lot at 36-39 F and by a lot at 90-93 F.  Whole flours tend to produce more sour starters and  bread too.

So if you want more sour, you need to promote the conditions that lead to more LAB and less yeast in the SD starter and the best way to do this is to use a whole rye starter and retard it at 36 F for a very long time, 8-10 weeks works best for me.  At low temperatures, both yeast and LAB reproduce at very slow rates compared to room temperature but LAB will outproduce yeast by a factor of 3 to one at 36 F.  So the longer you keep the starter at 36 F the more LAB to yeast your starter will have and when you inoculate your dough with it your bread will be more sour as a result.

At high temperatures 93F LAB out produce yeast by a factor of 13. which really puts the sour on overdrive.  So if you build your rye starter for long term storage at 92 F over 12 hours, this will limit the reproductive rate of yeast at puts LAB reproduction rates on steroids.  This turns out to be the most important thing for making sour bread.  The cold retard helps but the reproductive rate is so low it takes forever (weeks) to really make a noticeable difference.  But building the starter at 92 F makes is very sour very quickly.

Then if I wanted a really sour bread, I could build the levain from this starter by taking a bit of of starter that is loaded with LAB vs yeast and build the levain over 12 hours at 92 F too.  Now when this levain hits the dough it is packed with many more LAB than yeast in the normal SD starter or levain so there is much more acid being produced than CO2 gas in the dough no mater what temperature it is fermented at - and more sour bread results within limits..

If you develop the gluten and ferment the dough at 90-93 F and then retard it at 36 F for the proof - even more sour shoud result.  But there are limits to all of this.  To much acid breaks down the gluten and the bread won't rise.  So a balance is required to get more sour yet not so much that the proof fails. 

Too get this balance, my own experience is that if I build a whole rye starter over 12 hours at 82-84 F and retard it for weeks along with building the levain at around 82 -84F, doing the dough development and ferment at room temperature and then retarding the dough for proofing in the fridge I get a sour bread that rises well.    If I try to push the starter, levain builds, dough manipulations, ferments and proofs to 92 F the dough breaks down or it is way too sour.  But other combinations work just as well and finding hat works best for you and your schedule is the fun part - and everyone's starter is different as well.

Temperature is your friend.  The general rule still applies, by limiting the yeast reproduction rates while promoting the LAB reproduction rates by using temperature,  should result in a more sour bread - within limits.  It's all biology and science if you ask me.

Here is a temperature chart that shows Ganzel's data on LAB to yeast reproduction in one SD culture

 

Reproduction Rates of LAB and YeastL/Y 
T(°F)T (°C)L. SF IL. SF IIYeastRatio
     36         2 0.0190.0160.0053.787
     39         4 0.0260.0220.0083.147
     43         6 0.0350.0310.0132.634
     46         8 0.0470.0430.0212.222
     61       16 0.1440.1500.1141.265
     64       18 0.1870.1980.1631.145
     68       20 0.2390.2590.2251.064
     72       22 0.3010.3320.2951.021
     75       24 0.3740.4160.3651.024
     79       26 0.4530.5080.4141.094
     82       28 0.5350.5980.4171.284
     86       30 0.6090.6720.3461.760
     90       32 0.6580.7060.2023.255
     93       34 0.6570.6710.05013.127