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Apparent Hydration

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Frrogg1son's picture
Frrogg1son

Apparent Hydration

 

Can't tell you all how much I appreciate all the posts.  I've learned more in two years at the Fresh Loaf  than I learned in twenty years of buying and reading dozens of books on bread, not that I'm complaining about the books.  So many have been great.  I am quite indebted to Amy Glezer, Dan Leader, Joe Ortiz and, of course, the man they used to call Brother Juniper!  Also very grateful for the renegade Charles Van Over, wherever you are!

 

The following questions have been on my mind for some time.  Someone please help me to put this all to rest!  I have a three-part question regarding what I call "apparent hydration".

 

First part:

 

If I create a dough using 500g of AP flour, 300g water, 10g salt and a minimum of yeast, I produce a dough which I recognize as being 60% hydrated, both by look and feel.  I know how it should be kneaded, how it will shape and how it will develop in the oven.

 

What I don't know is this:  If I add 56g of butter to that same dough, whether at the beginning of mixing or even added to the dough after the gluten is well developed, how can/do I account for the changes the butter brings to the apparent hydration of the dough. If  I add 10% of the flour weight in butter to my 60% hydrated dough, the dough becomes much more sticky and appears significantly more slack.  I appreciate that average American butter has water content in it.  I don't know how much of the 56g is water.  But it seems to me that the "apparent hydrating effect" of the butter addition goes way beyond that little bit of water in the butter.  I am sure that I would find an even greater impact if I were to add 10% olive oil (by weight as a percentage of the flour weight) to a 60% hydrated dough, even though olive oil has, to my knowledge, no water in it at all.

 

So, does fat effectively contribute in some way to hydration, or at least to "apparent hydration"?  Or is the effect merely conditioning (for lack of a better word)?

 

Has anyone ever created a factor to account for the effect of fat on dough?  If I want a 60% hydrated dough, with a 10% butter content added or a 2% olive oil content added, to have more or less the same apparent hydration as the same dough without the fat, by how much do I adjust the water content down?  Is there a one to one ratio? Meaning that if I add 56g of butter to a dough but don't want it significantly more slack, should I reduce the water content by 56g?  I think I've tried that and the dough was too stiff.  Is it a 1.0g fat to 0.5g water ratio?  Or has this simply not been studied or quantified?

 

Have I made myself understandable?  Does Hamelman address this in "Bread"?

 

Second part:

 

If I take the same 500g AP flour, 300g water, 2% salt and minimal yeast dough and mix it as a straight dough, I get what I expect in terms of hydration, elasticity, extensibility, and so forth. However, if I mix half of the flour and half of the water as a pre-ferment along with a pinch of yeast, the final dough seems to me to be meaningfully more slack and extensible because of the addition of the biga or poolish..

 

Don't get me wrong. I don't at all dislike the effects of a pre-ferment on dough.  A poolish is one of the greatest inventions the Poles ever brought to Vienna!

 

But if I want to make a bagel dough at 60% hydration but decide to create a preferment with part of the ingredients, should I compensate for what seems to me to be the super-hydrative-effect from the preferment by reducing the final mix to something like 55% hydration?  Put another way, does the addition of a poolish allow me to reach an "apparent hydration" of 60% by using only 55% water?  Or is what I am experiencing merely another conditioning effect?

 

Third part:

 

Same lean dough but the addition is 10 to 15% white sugar?  I've always thought that adding 50g of white sugar to a formula for a sweet dough is the equivalent to adding 50g liquid to the final formula, even though sugar competes with flour for liquid.  But I've never actually seen this documented.  Again, is there a ratio of sorts to allow me to compensate for the effects that sugar bring to a dough?

 

So, in summary:

Should formulas adjust hydration to some extent for the addition of fat?

Should formulas do the same for pre-ferments?

Should formulas do the same for sugar?

 

Best, Bruce

jcking's picture
jcking

Heavy Cream, 57% water, 36%fat

Butter milk, 91% water, 2% fat

Milk, 87% water, 4% fat

Beer, 93% water

Sour Cream, 72% water, 19% fat

Jim

Chuck's picture
Chuck

Should formulas adjust hydration to some extent for the addition of fat?

For calculating "hydration", there are tables of exactly how much of various fats are actually water (some for butter and for eggs, none for oil). There's such a table here on TFL  ...somewhere. When I knew where it was, I printed it out so I'd always have the hardcopy for reference.

I've had the same question about "apparent hydration", but have never found an answer that fully satisfied me. So far as I know, there's no formula nor rule of thumb nor coverage in any book of the topic. Most often the amount of fat is small enough that not knowing the exact "apparent hydration" is not a big deal anyway.

When it does matter, it's already included in a recipe. When you're making up your own recipe, you may not get it quite right the first time and need to "adjust" it by feel. I've come up with my very rough own rules of thumb for "apparent hydration" in a few cases, but they're nothing I'm confident of  ...and with more experience I'm no longer too sure they're even useful.

 

Should formulas do the same for pre-ferments?

The "hydration" of a recipe doesn't change when pre-ferments are used. It's still the total amount of water as a percentage of the total amount of flour.

While the "apparent hydration" may change a little as you note, I don't know of any way to calculate the extent of the effect. Again based on the experience of having tried it and "adjusted" as necessary, the effect is already included in recipes. And again if you make up your own recipe, it may not be quite right the first time because of this effect.

 

Should formulas do the same for sugar?

Unless you're making a very sweet loaf, the amount of sugar is small enough to not make much difference. Again published recipes have already been "adjusted" based on experience and so already include this effect.

If you use honey instead of sugar, the honey will contribute some water and hence will change the "hydration". The same tables that give water content of a lot of fats also give water content of a lot of sweeteners.

proth5's picture
proth5

Unfortunately for you, I have recently been drilled on your second and third part questions.

Second part

Because protease will break down some of the gluten bonds and because protease acts more quickly in a wet environment, a dough made with a liquid pre ferment will feel "wetter" than a straight dough or one made with a firm pre ferment.  Generally a formula is written to a certain hydration percentage and water held back (or water added if you are mixing in a very dry environment) so that the actual water used produces a dough with the right consistency.  The formula isn't changed, it is the execution that is changed as there will be many other variables that go into the proper consistency of the dough.

However if you find that you consistently hold back the same amount of water, you may wish to re write your formula to the correct amount of water.

But how the dough feels is your most important objective.  I have seen world class bakers just add water until the dough was the right consistency.  The important thing is to learn to evaluate the dough before the mixing process is complete so that you can make the adjustment soon enough.  But it is good to be aware that doughs with liquid pre ferments may need less added water.

Third part

Sugar, although hygroscopic, acts as a liquid in doughs.  So, if you add sugar, it is the equivalent of adding a liquid.  Just how much liquid is not something I have seen documented, but the fact that is does act as a liquid - well - for me I can actually hear the voice of "my teacher" as this was drilled into my brain.

But again, we don't add sugar to hydrate a dough - we add sugar to impact the taste.  So the percentage of sugar is determined by taste.  Once again, you may start with adjusting the hydration in your formula, but it is the dough that will tell you the impact of the sugar.  Hold back a portion of the liquid when you first start the mix.  If you consistently hold back the same amount, you know how to adjust your formula.  Again, you need to learn to tell if the right dough is developing early in the mix and adjust hydration accordingly.  There will be so many other factors that will go into the actual amount of water in the dough that it is impossible to be so exact.  (I've heard "my teacher" tell me one day that it is the dew point that determines the need to add extra water - not the moisture in the flour and then very shortly after tell me that it isn't the dew point, it's the "thirst" of the flour.  This used to make me nuts.  Not anymore.  What is important is that "my teacher" told me "You must feel it on the fingers." with that, you will never go wrong.)

I'm a big proponent of accurate formulas and I love me my baker's math.  But just as logic is the beginning of wisdom, the written formula is only the beginning of good bread - you must learn to evaluate and adjust as the dough is being mixed.  The big dogs do it  I've seen it over and over.

Hope this helps.

Happy Baking!

Frrogg1son's picture
Frrogg1son

Thanks Jim and Chuck for your kind and thoughtful replies.  Both are helpful.

And special thanks to Proth5.  

My two dear sons are grown now (both bake bread!) and I've begun to downsize my own formulas for just the two of us and for giving away.  So it was a good time for me to get these questions out of my head.

 "I have seen world class bakers just add water until the dough was the right consistency.  The important thing is to learn to evaluate the dough before the mixing process is complete so that you can make the adjustment soon enough."  I have heard and read similar advice many times before and I have begun to really experience my own sense of KNOWING when a dough is 'just right' for me.   But somehow we often don't give ourselves the permission to live at that level.  I started baking years ago, Joy of Cooking, Better Homes and Gardens Homemade Bread Book, all straight doughs,all volume measurements, lots of yeast.  Do exactly what the books says.  Good for the 1970s.  It was a long time before I stumbled across Laurel's Kitchen Bread Book, then Peter Reinhart's first book (Brother Juniper).  All of a sudden I was reading and meeting Daniel Leader, discovering Amy Glezer's great book, meeting bakers in France, getting to know the great coal fired bakers in South Philadelphia, enjoying contacts with Peter Reinhart.    

And yet, despite my level of learning and experience, I was and am still being a slave to the book, the formula, the recipe, rather than listening to the dough.  I do know that it's communicating to me.  

Yeah, I've read about the bakers who "feel the air, feel the flour, feel the water".   The big dogs do it.  It's true.  

Thanks for telling me that the door is open and I can walk (run?) to the next level.  I've read enough of your posts to know that you know whereof you speak.

Thanks for the encouragement.

Best, Bruce

ehanner's picture
ehanner

Bruce,

Having read this thread, you have gotten some great replies. It seems to me that while there may in fact be a formula somewhere, that would solve your question, the fact that you knew enough to ask it says you already know the answer. You are a talented baker. I look forward to seeing some of your creations.

Eric

plevee's picture
plevee

US butter conains 14-16% of water but most of this is held in emulsion with the fat. One of the brilliant chemists on the site might be able to tell you how much of this is is available for release into the dough.

With doughs rich in fat there is also a greasing effect on the gluten which makes the dough seem looser or more hydrated.

Thank you for the very interesting questions and answers

nicodvb's picture
nicodvb

To what the other users replied I can only add a couple of advices: always use the same flour and always keep note of the effects obtained changing ingredients. Fats have a slackening effect of their own, even when they are water-free. In particular liquid fats like oils have a more pronounced slackening effect than solid (saturated) fats and even among oils there are some better than others: IIRC in Emily Buehler's book there's an explanation of the effects of various kind of fats on the gluten (better are saturated fats and worse are polyunsaturated fats; mono- (like olive oil) is in between. Search in this forum).

To compensate for the lack of consistence there are two possible ingredients: lecithin and egg yolks (still for the lecithins, but it has cholesterol). How much... dunno, lately I'm using around 5% respect to the flour weight but I'm still in a testing phase.  For sure I need to add way more lecithin that is generally adviced and it requires a lot of kneading in the machine to amalgamate perfectly in the dough. Better adding it in advance, possibly soaking it in the water several hours in advance.

 

jcking's picture
jcking

In reference to the fat conundrum, lipids end up replacing the protein film that surrounds the CO2 bubble. Polar lipid molecules stabilize the gas bubbles to a greater degree than the proteins. From 0% to about 2% by weight, all fats reduces loaf volume. The hypothesis is that at these low levels, the film is mixed protein/lipid and is less stable than either alone. From 2% to about 10%, loaf volume increases with increased polar lipids. Non-polar lipids have a more deleterious effect on loaf volume as the amount of non-polar lipids is increased.

Generally polar lipids include saturated and monounsaturated fatty acids. Non-polar lipids include polyunsaturated fatty acids. Lard, butter, egg yolks, olive oil and coconut oil are high in polar lipids, as are all dairy; thus improve loaf volume. Canola (who can stand the taste anyway?), corn, sunflower and soybean oils, margarine, and vegetable shortening all have high levels of non-polar lipids, which reduce loaf volume.

This info gleaned from Bread Science, by Emily Buehler, and from private correspondence with Dr Buehler.

Jim