The Fresh Loaf

News & Information for Amateur Bakers and Artisan Bread Enthusiasts

Measuring hydration

  • Pin It
lew_c's picture
lew_c

Measuring hydration

I mixed up my first batch of carefully weighed and measured dough with a target hydration of 65%. It came out a little more wet than I was expecting, though as a complete novice I don't really know what to expect. So I tried to measure it: Took a 27.4 gram sample, pre dried it in the microwave and then put it in a 400 degree convection oven for 40 minutes till it seemed dry and the dough was very dark brown and got a 14.4 gram reading which is ~48% . I've put it back in the oven at 250 and will leave it for 4 hours and re measure. But I was wondering if there is a protocol for this procedure with dough.

Edit:      Perhaps true hydrates are formed?

Edit:      Well, obviously, so I guess the question is how strong are the bonds?

Thanks

 

lew

dabrownman's picture
dabrownman

bread does not take into account the water that is in the the grain itself.  100 g of flour may have 7-12 g of water in it.  Since there is no way to know how much water is in the flour, we just ignore it because it doesn't make much difference in the scheme of things  If a total weight for flour and water is 888 g for a loaf of bread that is designed to be 71% hydration - it has (888/1.71) = 519 g of flour and (888-519) = 369 g of water.  369/519 =71%

Love your experiment Lew.  When you get done, it would be a miracle if it come out to 65%.  I don't know of any protocol for doing what you are doing so maybe you are inventing it as you go? 

happy baking

Les Nightingill's picture
Les Nightingill

Actually I believe 7% - 12% range of water content in flour does make a difference. I can feel the difference in dough handling when I'm baking at the coast vs. inland at 4000 ft elevation. I'd be curious too if those in the US midwest experience similar differences between their dry winters and hot/moist summers.

Hamelman mentions in "Bread" that, having mixed the weighed ingredients, you should then "correct the hydration", which I take to mean "correct for any difference in the flour's water content". Of course, that becomes a subjective factor, and difficult to describe in writing.

I think we mostly ignore it b/c it's a bit too hard to think about!

lew_c's picture
lew_c

Thank you.  Some years ago my wife made bread almost daily in a bread machine and she reports that she would sometimes have to adjust the water when she got new flour. But she did not measure dry ingredients by weight so its unclear if that means anything at all. 

lew_c's picture
lew_c

Thanks for the input. I repeated the experiment from the same batch of dough and got approximately the same result so I assume I made a mistake in my original formulation of the dough. As spare time allows I will run experiments to see if I can figure out what's going on. If I come up with anything meaningful I'll report back. BTW this same method should work for determining the moisture content of raw flour.

 lew

lew_c's picture
lew_c

And yes, definitely getting senile - sigh, anyway this will set things straight - hopefully.

"From the Annual Book of ASTM (American Society for Testing and Materials) Standards, the total evaporable moisture content in Aggregate (C 566) can be calculated with the formula:

p = (w – d) / d

where p is the fraction of total evaporable moisture content of sample, w is the mass of the original sample, and d is mass of dried sample."

gorbo's picture
gorbo

Maybe, if there are a food laboratory near you - they can burn your sample and measure the real quantity of water,

They can do the same just with flour e identify que contents of water, probably they will find a variety of results. There are many variables envolved in hidration.

best wishes

lew_c's picture
lew_c

Thank you gorbo, but it turns out I was disoriented by the multiple meanings of hydration and only evaporable water content is relevant to baking – doh!

I weighed, dried at 250 for 8 hours, and weighed again 206.3 gm of white flour and got a result of 12.9 percent. That seems a tad high for this time of year, and I only did it once, but I was careful about my technique and I'm using a calibrated Ohaus scale accurate to 0.1 grams so I'll accept that for the time being. I'll run it again with white and whole wheat in the next day or two. I understand that batch to batch variation would be irrelevant and in practice will use only average values and not test each batch. My objective is to be able to test dough that doesn't seem right so I can better understand my errors. At this point I'm running the tests on raw flour for their pedagogic value, it's been generations since I was last in a lab.

lew  (BTW very sorry they dropped your show, gorbo)



Mini Oven's picture
Mini Oven

That could be a fun topic. Because with my rye breads, I like to use ingredients that hold hydration, more so than just the flour and hope to get the steaming effects to add more open crumb while the loaf bakes free of forms.  Chia for example holds a lot of water.  And it gives it up too!  Flax is another one.  Steamed rolled grains hold water.   So do fibrous ingredients.  How much water should they give up to keep us munching on them?  When is moisture content too dry?

Naturally heavy fibre doughs tend to get dry when baked.  They would be much more satisfying when the hydration is also raised.  Who wants a mouth of dry, grab the glass, bread?  (someone who sells drinks)  Or should it a dunking bread?  One for soup, one to float in soup...  onion soup with floating bread and melting cheese under the broiler.  Oops, sorry for the distraction.  Moist bread for dry meat.  Dry bread for moist fillings and toasting. 

I don't think there is one hydration that fits all breads. That would kill the variety and certainly the fun.  I remember that before I got to exploring bread, I stuck to one or two basic recipes.  Baking Freestyle, I started out based on the liquids.  Once I learned to measure using the flour as a guide, based on flour weight, I could add ingredients with more reliable outcomes.  That was the info I needed. I broke away from a fixed notion of starting with hydration. 

Study the different flours, find out what makes them unique, combine them for your own pleasure and add water to get the dough to behave the way you want it to.   That's the start.  

lew_c's picture
lew_c

"Naturally heavy fibre doughs tend to get dry when baked.  They would be much more satisfying when the hydration is also raised."

Thank you for that tip, could you recommend a hydration I might try for my very high fiber bread?

Mini Oven's picture
Mini Oven

:)

lew_c's picture
lew_c

This is my basic brick bread. It provides a “hearty” substitute for meat in most of my vegetarian meals. I spritz the dough when I turn the oven on, again when the oven gets up to temp and again when I lower the oven temp. If you have dentures the crust will take 'em out. My apologies to those whose refined sensibilities are violated, also for mixing weight and volume measures–that I'll have to fix.  BTW I use a 40 minute period for the bread to autolyse and about that much time after to incorporate the salt ;) 

800gm bread flour

150gm barley

150gm spelt

100gm whole wheat

100gm rye

65gm buckwheat

65gm milk protein

40gm Himaize

40gm amaranth

20gm oat fiber

25gm gluten

2Tbs. flax seed meal

2tsp. salt

2tsp. psylium seed

1Cup 50/50 preferment

And thank you, the help is appreciated.

Mini Oven's picture
Mini Oven

What happens when you drop the 25g gluten and the 40g Hi-maize from the recipe?  

I believe these two ingredients are making for a heavy loaf.  Resistant starch can be eaten raw, mixed into water or yogurt easily without the thickening effect of heat (baking.)  I like potato starch myself.  

The non-gluten flours and ingredients add up to just 395g under one third of the flour, so I don't see any big problems making a decent loaf. 

How much water are you adding and are you soaking any of the whole grains and seeds before combining with bread flour?  I would try to put as much hydration as possible into the loaf.  Much higher than 65% 

Two teaspoons (under 1%) of salt seems incredibly low adding to the density.  What do you think of one Tbs? (1.5% or 18g)

lew_c's picture
lew_c

Thank you, I will try 85% and 18g salt and no Himaize. It's just the two of us so I don't bake that much bread and progress is slow. But once I've settled those issues I will try lowering the gluten. As my loaf has a formidable crust which seems to satisfy the same needs as those met by meats and crispy fried foods, I don't want to loose that even for a lighter loaf. And from previous loaves with less gluten I think gluten may be an important contributor to the crust. Once I think I've got this bread as good as it will get I'll pursue other lighter loaves.

Again thank you for the assistance.

lew

The Yakima Kid's picture
The Yakima Kid

Yes, the amount of water in the flour can and will make a difference. Higher altitudes and cloudy days have lower barometric pressure, so those days tend to require a little extra water due to more rapid evaporation. Higher altitudes also tend to need a higher oven temperature to set the structure more rapidly before the product dries out or suffers from excessive oven spring. Some recipes benefit from a slight increase in flour as well as in water because of the ratios to other ingredients - fats, sugars, etc. I find reducing sugar slightly at higher altitudes reduces excessive browning.

My baking is by weight, and I have found differences between both batches of the same brand of flour, and between different brands of flour. I find that Stone-Buhr is the most consistent high end brand - possibly because it is shipped through the fewest humidity and altitude changes before it reaches me.

The Yakima Kid's picture
The Yakima Kid

Flour will absorb water in humid conditions.

For bread baking, I'm afraid I wind up going by the "hand" of the dough even after weighing all of my ingredients.

lew_c's picture
lew_c

I have made only 5 batches of dough since my last post here. But I also got a mill and berries so I have not been making the bread described above but wheat, spelt and barley breads. The last batch is in the fridge till 7:00 AM tomorrow and it is the most like the one described but I don't have the numbers on it yet.

 

Following Mini Ovens advice, for the first three I aimed for 80% hydration and got measurements of 89.5%, 93.7%, and 93.5%. For the fourth I aimed for 85% and it measured 96.6%

 

These breads were noticeably better in terms of moisture than my previous breads and the first two were very tasty. Unfortunately I had been trying the “reserve some dough” method of starter maintenance and forgot to reserve some for the next loaf. That loaf was kinda bland but my new starter is beginning to come together and I am really looking forward to this next one.

 

I have tested one flour at 12% moisture content which is consistent with the equilibrium content of wood for our climate. I will test more eventually but for now I'm defaulting to 12%.

 

The latest bread had a target of 80% hydration and contained 1630g of hydratables, flours + dry fortifiers. Not counting the moisture content of the ingredients, this would require 1304 grams of water, which is what I used. At 12% moisture content there are 195g of water in the dry ingredients so the dry weight is 1435g. Incorporating those figures I expect to get a measured Hydration of

 

wet weight = 1630g + 1304g = 2934

dry weight = 1630g – 195g = 1435

 

((2934g – 1435g) / 1435g) * 100 = 104.5%

 

I have a sample drying now. Tomorrow I'll post the results. From the previous runs this seems too high.

Nothing here is guaranteed correct—too many senior moments to be certain of anything anymore.

 

Thanks for all the help ... its' helping :)

largeneal's picture
largeneal

...apparently has unintended benefits (heating essentially makes proteins more accessible for binding & yeast action).  

So, if you're really bored and want to add an experiment, prepare two loaves - first one will use NON-heated flour, second will involved heated flour (but you'll have to add the water lost during heating back to the flour to ensure both loaves are hydrated equally).  Would be great to have a side by side/see if there's any enhancement by going about it this way.  Great work!

http://www.sciencedirect.com/science/article/pii/S0023643803001178

http://server.fst.uga.edu/kerr/FDST%208080/Articles/Creep-Stress/Rheo%20Bread%20JCS%2003.pdf

lew_c's picture
lew_c

Thank you for the suggestion but for now I'm more concerned with achieving accurate hydrations.

lew_c's picture
lew_c

I quick report that by measurement the hydration was 93.9% not even within 10% of calculated value. So more practice, checking of algorithms and care.  More disappointing was that unavoidable outside (the kitchen) events led to excessive first rise time and a too tart bread.  Would have given it to the pig but no time to make another so I'm eating it myself.  My wife said she would help eat it but had to run off to a quilt show in Paduka to for a week.

Mini Oven's picture
Mini Oven

Warning: Exactness of hydration might give you May madness.  :)

Most flours are sold with 15% hydration but this isn't calculated when trying to hydrate the flour with water for bread.  This also changes slightly with storage conditions.  Count your flours, any ground up nuts or GF flours as the total flour weight.  Count your dried milk as a GF flour.  I would go so far as to separate the gluten flour from the gluten free flours.  If your GF list adds up to less than 1/3 of the total flour, vital gluten many not be needed.  You want to be in the ball park and be able to describe the dough so others know which way to tweak the recipe incase 2% more water is needed.

Seeds and fibre that soak up a lot of water (oat fibre, psylium, flax, vital gluten) should be soaked first or at least tested so you know how much added water is needed into your recipe above the bread flour "norm" of 65% - 70%.  Added gluten should be sifted into the flours to prevent clumping.