The Fresh Loaf

News & Information for Amateur Bakers and Artisan Bread Enthusiasts

Extensibility & Gluten Structure

albacore's picture
albacore

Extensibility & Gluten Structure

I was making bread today and the particular recipe I was following called for a 1-2 hour autolyse. This is longer than I normally like to do. And as it happened, I had to go out and the autolyse became a 4 hour one!

Well I carried on with the breadmaking, but the dough had the consistency of toothpaste, but did have some strength after mixing. We'll see how it bakes tomorrow.

So I got to thinking, is it possible to have dough that has a well developed gluten network and has good extensibility, or are they mutually exclusive?

 

Lance

 

kqa100's picture
kqa100

From my admittedly limited experience, not only are they not mutually exclusive, they can be mutually reinforcing. I do a 4 hour autolyse on purpose, and I find that a few strong folds are just fine to get it reorganized. (I'm using a 20/80 WW/bread flour mix.) 

Sometimes I also use Trevor Wilson's overnight quasi-autolyse method which really develops all the gluten you need, though I find it's a bit too much if your kitchen is hot. Method here: http://www.breadwerx.com/champlain-sourdough-recipe-video/ 

Anyway all of this is to say that I'm a big fan of pushing the autolyse for both extensibility and gluten reasons!

mwilson's picture
mwilson


Lance, how did the toothpaste bread turn out?

albacore's picture
albacore

Well, it wasn't a great bake - poor loft, tight dry crumb, poor ears, thick crust. Can I blame all this on the long autolyse? - probably!

However, it was an unusual bake because it contained 50% semola rimacinata. Typical that external factors spoil your breadmaking when you are using expensive flour!

I really need to repeat the bake with a 1 hour autolyse to evaluate the difference.

I think I've got my head round extensibility vs gluten structure now: it seems to me that if extensibility is created by factors such as glutathione (eg nutritional yeast), or addition of spelt flour or L-cysteine (some dough improvers) then gluten won't be compromised.

But if extensibility is coming from a long autolyse or possibly even a poolish, then gluten structure may well be compromised.

Lance

mwilson's picture
mwilson

Semola rimacinata

I can confirm that semola rimacinata is not very suitable when applying an autolyse. This flour typically gives poor results when assessed rheologically. Testing with the Brabender farinograph will highlight inferior gluten properties, notably the property of Stability (measured in minutes) will be low, possibly around 4. This property describes the mixing tolerance of the gluten and from this you can also infer a tolerance to fermentation.

When stability is low the overall processing time should be equally limited to match the flours performance. Hence why pane di Altamura is mixed and baked within just a few hours. When selecting flour for a process that is long including any retardation e.g. overnight pizza, then a flour that has a higher stability will be required. Very strong flours will have a stability greater than 10 minutes.

Even without any fermentative activity an autolyse with semola rimacinata will clearly demonstrate its poor gluten properties and its rapid degradation.

 

Extensibility

When bakers describe extensibility they typically do so in a way that connotes a slack dough which gives little resistance and is perhaps less elastic. However, this is not quite how extensibility is defined with rheological testing, rather extensibility is defined as the length of stretch that can be obtained prior to breaking. Extensibility is an inherent property of gluten and without gluten there would be little to no extensibility available.

It should be noted that semola and particularly semola rimacinata have poor extensibility giving P/L (Chopin alveograph) values above 0.7, typically between 1-2. At an optimal hydration durum flour makes doughs that are more claylike or playdough-like. See a previous post of mine discussing this here.

Always a good read: dough strength: evaluation & techniques (SFBI)

 

Michael

albacore's picture
albacore

Thanks for that wealth of information, Michael; I was aware that semola rimacinata could be suspect in the gluten department and you have explained that more fully.

However I was simply following Dietmar Kappl's Homebaking.at Bocca Pratese recipe, which seems to have worked for him.

I think it was just my unavoidably long autolyse that gave the disappointing results. Having said that, the crumb wasn't as bad as I predicted:

 

Lance

mwilson's picture
mwilson

Looks soft and the durum carotenoid pigment is showing through. Good thing the durum was at only 50%, otherwise it might have been a different story...

 

albacore's picture
albacore

Thanks Michael - and good luck with your Pane di Altamura! Do you think Mockmilled UK semolina would make an acceptable substitute for semola rimacinata? Most seems to be milled from Italian durum wheat.

I've used it so far at up to 20%, but not 50 or 100%.It certainly seems to have the right fineness of grind.

 

Lance

mwilson's picture
mwilson

Lance, I don't do any home milling so I'm not sure I could give a qualified opinion on that one. However, my general view of home-milling is that it to be a novel endeavour.

For the same grain I would expect home-milled to have inferior performance.


Michael