Today I experimented a bit with the hydration levels of two different flour types: Classical wheat flour (Tarwebloem) and spelt flour. I did a measurement series with 65%, 70%, 75%, 80% and 85% for wheat and 65%, 75% and 85% for spelt flour to determine the properties of the dough after autolysis. I figured that for the breads that I usually bake, a hydration level between 65% and 75% is optimal for wheat flour. For spelt I am still a bit uncertain, but I get the feeling that 75% might be already too high for a good gluten structure to form.

# TL;DR

Good gluten window

Wheat flour:         65%-80%
Spelt flour:         65%-75%

Easy zone (not too much sticky)

Wheat flour:         65%-70%
Spelt flour:         65%-80%

I have the feeling spelt dough behaves 5% nicer than wheat flour when making the dough
At 75% and higher hydration, the dough viscosity becomes very liquid
This does not say anything about taste, this is about dough behaviour only

# Hydration levels / Baker’s Percentages

Baker’s percentages (or baker’s math) is in a nutshell the percentage of a single igrediant per flour weight:

               m(ingredient)
percentage = ----------------- x 100
              m(flour_total)

For instance, a bread with 75% hydration has 75 parts water per 100 parts flour. In number, for 1 kg flour you would need 750g of water.

This formula is often used to quickly scale recipe ingredients. If you have a recipe, you can easily scale the ingreadients up or down, or modify the hydration level.

If you have multiple flour types, m(flour_total) is the sum of all different flour types.

Find out more about the baker’s percentage on theperfectloaf.com.

# Measuring the hydration levels

Because every flour behaves a little bit differently, I like to try out a series of hydration levels before making bread. After some time one gets a feeling how the dough for a recipe should look like and behave. To achieve this goal, one might need to adjust the water content a little bit, as the same flour type sometimes gives a bit siffer or softer result with the same amount of water.

To learn how my flour behaves, I did a measurement series with wheat and spelt flour.

For wheat, I did 65%, 70%, 75%, 80% and 85% hydration levels. For each of those levels, I put 40g of flour in a small bowl, together with the corresponding amount of water, mix it throughly and let it stand for at least half an hour to let it soak (autolysis). After that, I did the gluten window test and made a picture for future reference. The gluten window tells us, how good the protein network if and this determines, how good the bread will behave. A good gluten network is essential for a soft and fluffy interior to form and to hold.

For spelt I did the same, but just with 65%, 75% and 85% hydration. Here I am still basically experimenting on a coarse level, as I have not mastered this flour type to the point, where I believe that a finer level gives me any advantage.

# Wheat flour

So let’s start with the gluten window pictures of the different hydration levels

65% hydration 70% hydration 75% hydration 75% hydration (another time) 80% hydration 85% hydration

First: Every hydration level here should in principle work. The only problematic one could be 85%, where the dough slowly starts to tear apart. So, for my wheat flour I believe anything between 65% and 75% is fine from the perspective of the gluten network.

From the perspective of the dough viscosity, I tend to go to lower hydration amounts. 65% is already a bit gooy, and it only becomes messier towards higher hydration levels. Perhaps I need to read up about different folding techniques, but right now I’m very afraid that any shape would just liquidify and ultimately turn into a pancake, rather than a bread.

Viscosity of the wheat dough at 85% hydration

# Spelt flour

Spelt flour behaves slightly different than wheat flour. I find it interesting, because I feel that the taste is a bit more hearty and I believe it is easier on your gut, but both can be just a subjective feeling caused by brainwashing of enough people around me by a generation of health food shop owners so that I started to believe it at some point as well. Anyways … :-)

For spelt flour I was less thoroughly in the number of measurements. Here I only wanted get a rough first impression, but also look a bit more into the consistency/viscosity properties of the dough. If possible also find a relation between wheat hydration and spelt hydration levels that allow me to understand the behaviour of spelt dough a bit better.

# Dough Viscosity/Consistency

Let’s start with a visual comparison of the viscosity of the dough (see also the header picture of this post for a similar series for wheat flour)

Visual viscosity comparison of spelt at the different hydration levels

Now let’s compare this series with the wheat flour

Viscosity of 65% wheat flour Viscosity of 75% wheat flour Viscosity of 85% wheat flour

Note: The pictures are misleading, as I spread out the spelt flour dough more than the wheat flour dough. What I write is based on how the dough feels, as opposed to how the pictures look. Don’t get confused/mislead by the pictures!

In general I’d say, that the spelt flour is like 5% dryer than the equivalent wheat flour. The 75% spelt flour looks more similar to something between the 75% and 85% wheat flour. The 65% hydration levels of wheat and spelt look the same, but when dealing with the dough, I had the feeling that the spelt one feels less moist and less sticky. At 85% I believe that the wheat dough was very sticky, where the spelt flour was more comparable to the 75% wheat flour.

At high hydration levels it becomes difficult to deal with the wheat dough, but the spelt dough was still ok. Here I believe that the spelt dough was less liquid and more comparable to a 75% wheat flour level.

As a rule of thumb, I’d say, that for the spelt and wheat flour that I had used in this experiment, spelt behaves like a wheat flour dough with 5% less hydration than the spelt one. For instance, a 75% spelt flour behaves like a 70% wheat flour dough.

Let’s have a look also at how the consistency of the spelt dough looks at different hydration levels:

Consistency at 65% hydration level Consistency at 75% hydration level Consistency at 85% hydration level

All of them are very sticky, and one needs to water the hands properly to avoid the dough stick to your fingers constantly.

# Gluten Window for the spelt flour

Similar to the wheat flour, I did a measurement series with 65%, 75% and 85% hydration levels also for spelt flour.

65% hydration 65% hydration (another one) 75% hydration 75% hydration (another one) 85% hydration

Here I am in dubio. I believe that 65% and 75% are ok, although at 75% the gluten window already starts to somehow tear apart. At least more than compared to the wheat counterpart. 85% for this alone might be already too much, although I could form the gluten window and it was only tearing apart in the last bit. I might still work, but I can clearly see that the gluten window of wheat flour at 85% hydration levels is stronger than with spelt flour. This is a bit sad, because I have the feeling that spelt is easier to deal with at such high hydration levels :-)