Sour Dough Hydration Experiment

Over the weekend of October the 13th and 14th I made three sour dough loaves varying one or two parameters to see what I can do to make a good, consistent loaf (which is tough to do with sour dough.)  My main goal was to gain insight into a problem where the dough does not rise enough and results in a squat, dense loaf (a “discus”).

The theory that I have for this is that it is a gluten development problem and not a yeast problem.  I am not sure if I have fully solved the problem that I was (am) looking into, but I think the results of my experiments are interesting for what they do show.

Here are the symptoms:  Sometimes my dough goes through a sudden change during kneading.  It starts normally (just as a mass of flour and water) and through resting and kneading it is supposed to become a smooth, stretchy, silky dough that one can shape and bake and … voila! – delicious bread.  But occasionally, during kneading, when I expect the dough to start to feel smooth and springy it quickly begins to loose all structure and becomes grainy!  It can not hold its shape, is gooey, not stretchy, and tears easily.

I have tried kneading past this phase change, but the dough never becomes a smooth, stretchy mass again.  I have never seen a mention of this phenomenon anywhere and I can not workout what I am doing wrong.  I have called this “over kneading” but when over kneading is mentioned on the internet, it’s in reference to developing too much gluten and making dough that is too tight to stretch and rise.  Moreover, I really don’t ever knead all that much.  2 minutes for me is a lot (some doughs I knead often, but never more than two minutes at a time, and rarely more than 4 times in all.)

This grainy gooey dough produces a discus loaf that tastes OK, but does not have the right texture, or crust.

So what could be going wrong? Clearly it is a gluten development problem that more kneading is not going to fix.  So my thought was that it must be the amount of water I am using.  Dough with a high ratio of water to flour (say around 0.75 or 0.76) is very hard to handle, so my though was that I was skimping on the water, to make baking easier, but then the gluten, that needs water to form, was not getting enough, and thus never forming.

I tried baking three loaves with three different hydration ratios (0.75, 0.70 and 0.65) but (almost) exactly the same otherwise.  Each dough was quite sticky and hard to handle and I did not knead much.  I never got to the grainy, gooey stage, and each loaf was fine.  I think perhaps I will have to settle on on of these ratios and perhaps try really kneading for a long time, or with different methods to eliminate kneading as the culprit.  I also might try even lower hydration (0.60, 0.55 and even 0.50) to see if it might be the lack of water after all.  If it is not kneading (time or technique) nor hydration, then perhaps I will have to be more scientific (water hardness, pH …?).

So, I did not answer the question I wanted to, but I did learn something, so here are the three loaves and some conclusions.

Small Sour Dough Boule

Ingredients:

  • 300g bread flour
  • 1 tsp salt
  • 100g sour dough starter
  • 195 g water

Special tools:

  • brotform
  • dutch oven

Method:

In a medium sized bowl, add the water and starter to the flour and salt and mix to combine, scraping the flour away from the sides, bringing the dough together.

195 g of water for 0.70 hydration.

Cover and let sit for about 30 minutes.

Turn out the dough onto an unfloured surface and knead for a few minutes.

Sticky dough.

The dough will be very sticky, so use a scraper and wet your hands if it sticks too much.

Let the dough rise again for a long time.  I let it rise for 12 hours.  Then knead it a little again (really just a punch down) and shape it into a boule, firming it up by tucking the edges under with your hands (palm up).  Flip it over and place it in a brotform for final proofing while your oven heats.  You can now use some flour as it will not get mixed in, and will help you handle the dough.  In fact you will need the boule well floured (I use flour and wheat bran) so that it will easily release from the brotform.

Sorry, a terrible photo, but the dough is looking much better now!

Put a dutch oven in your oven and heat to 250oC.  After about 30 minutes, turn the boule out and score it with a sharp knife or razor, to allow it to rise evenly.

I scored an “X” in the top.

I like to turn the boule out onto a silicone mat that fits in the dutch oven.  It is easier to transfer into the oven like this and the silicone offers some insulation and keeps the bottom crust from burning.  (I prop the mat up on a crumpled aluminium pie tin for more insulation as well.)

Bake the bread in the oven for 30 minutes with the lid on, then another 5 to 7 with the lid off.  This will give the crust some colour, so you can judge when to take it out, when it looks good to you.  The internal temperature should reach at least 90oC.

Take it out of the oven and let it cool on a rack.

I like to put my ear close to it and listen to the crust crackle as it cools.

Done!

Notes:

My starter just sits in a jar on the kitchen window sill and I add some flour and water to it about every day.  Sometimes I will skip a day or two, and put the lid on the jar to stop it drying out too much, or even put it in the fridge if I am not going to make bread for a while.  (When it comes out of the fridge I discard the top layer and feed it for a few days before using it, to get it cookin’ again.)  I don’t measure the amount of flour and water I add, nor the gas that escapes (water and CO2) but I guess that the whole mixture is at 1.0 hydration (i.e. 50/50 flour/water).  With this assumption, you can use this formula to adjust the overall hydration for this (300g flour) recipe:

(Mass of water in grams) = 350h – 50

where h is the desired hydration ratio.

I made three loaves, one at h = 0.7 (above), one at 0.75 and one at 0.65.

h = 0.70 (left) and h = 0.75 (right)
h = 0.65

Each of these loaves were perfectly fine.  The dough never went grainy/gooey and indeed, was quite elastic.  Each loaf rose well and looked good, with a good crust.  (I did not taste the 0.70 and 0.75 loaves, but the 0.65 loaf tasted good.)  I did not really learn anything about the question I wanted to answer (why some dough goes grainy and gooey and looses all elasticity) but I did learn a few of things:

  • Full disclosure:  I did not really do a great experiment, as I changed another variable for the h = 0.7 loaf.  I used plain flour (11% protein) as opposed to bread flour (13% protein).  This should result in less gluten, and indeed, this loaf did not rise as well as the other two (you can’t see it, but it was a little concave on one side), and its crumb was a little too random for my liking (I like large holes, but these are too far from spherical for me.)My conclusion here is that one can use plain flour, but if you have access to bread (high protein) flour you should use it instead.
  • The 0.75 and the 0.65 loaves were otherwise identical, so can be compared:
    h = 0.75. Nice open crumb.
    h = 0.65. quite even, but very closed crumb.

    The dryer loaf (0.65) was a good loaf, but the closed, dryer crumb was not the rustic type of loaf I was looking for.  It is a good option if you are looking for something more like sandwich bread.  The 0.75 loaf was the way to go, but this one was just a little under cooked.  I will have to adjust the time and temperature.¹

  • This is a small loaf (about half a kg) which is on the low end for my brotform.  Any smaller and I will have to proof in a small bowl using a well floured tea-towel.  Most recipes will make a loaf upto twice this size.  You will get more bread (and a higher crumb to crust ratio) but you will probably have to bake this for 10 to 15 minutes longer.
  • This sour dough did not require (or need) much kneading, as it needed to rise for a long time (12 hours) due to the yeast in the starter not being quite as active as store bought yeast.  This long rise time was enough to develop all the gluten it needed.  This is good, as the 0.75 dough was really hard to handle.  As this recipe is almost finalized, next I will look at perfecting French bread, where I might even go higher with the hydration!  This will not rise for an extended period so I will have to really knead it to get the gluten development.

When I have tested the right temperature and time for the 0.75 loaf I will post that recipe, but for now I will finish here and post the “sandwich loaf” version next.

¹ Edit (20181022): I have tried cooking the 0.75 loaf @ 230oC for 45 minutes and the loaf was good.   I will post this recipe as “Rustic Sour Dough Loaf.”  The inner temperature got to 97oC.