Experiment Three: More Hydration

A pizza with 60% hydration

In our last episode, we explored the effects of varying the amount of water in the dough. We ate a lot of pizza. We learned that a dough with 60% hydration gives a dough that, whilst being perfectly edible, is, dull, unresponsive and inert – not a million miles away from Plasticine. In contrast, a dough with 70% hydration – that is, where the amount of water weighs 70% of the total amount of flour in the recipe – is much more responsive and fun to shape, but is sticky as hell and can’t easily be shaped without adhering to your entire kitchen, in an almost needy sort of a way. You could make it more manageable by dusting everything it touches with flour, but then it would absorb the flour and wouldn’t be a 70%-hydrated dough anymore, which would rather defeat the purpose of the exercise. 

A pizza with 70% hydration. Note the slight difficulties with handling and adhesion.

It was an informative experiment, sure enough, but in terms of making our pizzas taste better, the practical implications of it were not immediately obvious. It’s nice to know that both 60% hydration and 70% hydration doughs weren’t ideal for making pizza, but that knowledge only helps us to avoid making bad pizza, rather than helping us make good pizza. In an attempt to find out something that might be more directly useful, we’re going to try a second, follow-up, experiment, in which we vary the amount of water in the dough in a more nuanced way. This time, we’re comparing 63% hydration and 67% hydration. Ah, the joy of obsessively tweaking tiny percentages – you cannot get more rock and roll than this.*

Wetter dough:                                                              Drier dough:
500g strong white flour                                                500g strong white flour
335g water                                                                   315g water
7g instant yeast                                                            7g instant yeast
10g salt                                                                        10g salt

The doughs were made up by hand, kneaded for five minutes, covered with oil and left to prove for two hours. They were then made into pizzas and dough balls.

Results:

Eyeball test: Visually, there was very little to choose between the doughs. Both rose well. The wetter dough felt perhaps a fraction more aerated than the drier dough, and was a little more tacky to the touch, but overall, any differences were slight. When shaping the pizzas, it was easy to tell which was which; the wetter dough felt slightly sticky, but was still quite readily rolled out with a rolling pin. The drier dough was also easy to shape, but wasn’t at all sticky. It had a decent amount of give to it, and was more responsive than the 60% dough from Experiment Two.

Visual differences between the two pizzas were minimal. To symbolise this, here is a picture of two other things that are visually quite similar. Note, however, that I did not want to punch the pizzas in their stupid, gormless faces.

Pizza test: Again, differences were not particularly pronounced. If anything, the drier dough had a slightly crisper crust, with a little more colour to it. That said, the wetter dough still made a perfectly good pizza. In an improvement from Experiment Two, I managed to roll out both pizzas to equal thicknesses. There were no discernable differences in flavour, and very little noticeable difference in texture or mouthfeel. As with Experiment Two, the drier pizza caramelised slightly more. I had thought this was due to the drier pizza last time also being thinner, but it may in fact be that wetter doughs need to be baked longer or hotter to get the same degree of colouring in the crust.

Flatbread test: Having done quite a few flatbread tests recently, I couldn’t face another one, so I didn’t do one. It’s a real burden having to eat two whole pizzas myself for these experiments, and the idea of stuffing two lots of plain dry dough into my face on top of that in the name of science really did not appeal. I have let down science and I feel bad. Please don’t tell Richard Dawkins.

Dough ball test: Each dough was shaped into a dough ball weighing 50 grams, and baked until lightly golden brown. Unsurprisingly, the wetter dough was a little easier to form into a ball, as it stuck to itself quite readily (this quality can be a pain in the neck when you’re trying to roll out a pizza without using flour, but it’s great when you’re trying to shape dough balls). Both tasted very nice. There was no differences that I could notice in terms of rise, colouration, or crust. However, there was a real difference in the crumb quality. The drier dough tasted – and you won’t believe this – drier. As a result, it was fractionally less enjoyable, and tasted a little more cardboardy. The wetter dough ball had a softer mouthfeel, presumably due to the additional water which hadn’t been baked out, but which was still present in the crumb. It also seemed more tasty and more pleasant to eat.

The Verdict

"You have been found guilty of not eating two identical pieces of dry pizza dough. The penalty for this is having to eat two identical pieces of dry pizza dough."

This experiment looks at quite a small difference to the recipe – the only thing that’s different between the two recipes is about 20 grams of water, which is barely more than a tablespoon. With that in mind, perhaps it shouldn’t be all that surprising that there wasn’t any noticeable difference in taste. The pizzas were also quite similar to each other – unlike Experiment Two, both sets of dough could be rolled out quite easily, though for a complete novice, the 67% hydration dough might have been a little sticky. If you wanted to shape your pizzas by hand, which is much more fun and skillful than using a rolling pin, I’d recommend the 67% dough. It was easier to manipulate than the 70% dough from last month, but more pliable than the 63% dough. For pizzas with a raised crust, I also expect there would be benefits to the crumb, with the additional water providing improved flavour and mouthfeel (I think it’s unlikely you’d notice much crumb difference on pizzas that are rolled out thinly). The 63% pizza was perfectly good, very easy to shape, and would make decent pizza anytime. But if it were up to me, I’d opt for the slightly wetter dough. 70% water was rather unmanageable, but 67% water strikes a nice balance between pliability and manageability.

*Oh. Apparently you can get a lot more rock and roll than this. Apologies for misleading you before.

Experiment Two: Hydration

Like bad 1980s football, baking is a game of percentages. When listing bread recipes, it’s common to see them expressed not in absolute quantities, but written in baker’s percentages – with each ingredient expressed as a percentage of the total weight of flour. As an example, my standard pizza dough would be written as follows:

  • 100% strong white flour
  • 65% water
  • 2% salt
  • 1.5% yeast
You’ll notice that the total adds up to much more than 100%. This is always the case with baker’s percentages, and it’s just one of many things that people can find offputting about writing recipes like this. When I first saw a recipe set out in this way, I thought it was needlessly obscure – if you need 10g of salt to make a loaf, surely the simplest way of
Chris Waddle's pet mullet

1980s football was a game of percentages. And also mullets. Percentages and mullets.

writing that is to say “you need 10g of salt to make a loaf”? Stating that you need 2% of your total weight of flour in salt seemed deliberately obtuse. However, there are two big advantages with this notation. First, and of most use to bakers, is that it means you can easily make any amount of a particular bread: whether you want to make one loaf or a thousand loaves, the formula will let you figure out precise amounts for each ingredient easily. The second advantage is that it makes it very easy to compare different bread recipes at a glance. Once you’ve learned to interpret BP, you can quickly work out what sort of loaf a recipe will produce. (For more on baker’s percentages, see the excellent Wild Yeast blog.)

Arguably the most informative line of a recipe is the percentage of water a loaf contains. Changing the hydration of a dough – that is, how much water it contains – can have major effects on the crust and the crumb; wetter doughs tend to give a more open texture with bigger holes, whereas drier doughs tend to have a tighter crumb structure. Drier doughs are generally easy to work with, whereas very wet doughs can tend to spread, slowly and menacingly, like a horrifying yet delicious B-movie monster. What all this means for the pizza maker isn’t immediately obvious. Pizzas, being flat, aren’t really noted for their crumb, so aiming for a ciabatta-like dough would seem to be a bit of a waste – if your pizza rises sufficiently high to show off your wonderful lattice of large air-holes, it’ll be much too bready to be a decent pizza. Nevertheless, changing the hydration of the dough will change the final product, somehow. Precisely how it changes it will be what we set out to discover in Experiment Two.

Hydration

It's important to get the amount of water exactly right

Given the rather arbitrary amount of water in the baseline pizza recipe, a useful first question to explore the effect of changing the amount of water would be to compare two doughs with different hydration. One dough, which I am going to call the “Wetter Dough” includes 70% water. The other dough, which I am going to call “Dame Margaret Harrington”, includes 60% water*. Both amounts feature in plenty of bread recipes, so both should give perfectly edible pizzas. The aim of this experiment is to put down a marker to show how different hydration affects the final products: our experimental question is “Which is preferable for pizza – a wetter dough or a drier dough?”.

[*On second thoughts, I’m not going to call this dough “Dame Margaret Harrington”. I’m going to call it the “Drier Dough”, as this may be slightly clearer for some readers. You may, if you wish, continue to call it Dame Margaret Harrington.]

Wetter dough:                                                              Dame Margaret Harrington:

500g strong white flour                                                500g strong white flour
350g water                                                                   300g water
7g instant yeast                                                            7g instant yeast
10g salt                                                                        10g salt

The doughs were made up by hand, kneaded for five minutes, covered with oil and left to prove for two hours. They were then made into pizzas, flatbreads, and dough balls.

Results:

Eyeball test: There was a striking visible difference between the doughs. The wetter dough had risen more, felt a little cooler, and looked more glossy. Although the surface of both doughs was relatively dry after proving for two hours, the wetter dough was noticeably stickier under the surface than the drier dough. It had also risen more, and had more obvious air pockets inside. The drier dough felt more putty-like, and tighter – when it was pushed, it had much less give. With the wet dough, in contrast, when it was pushed, the whole top of the dough moved, not just the part of the dough immediately local to the prodding. In other respects, the doughs look identical. This difference was so obvious that even when I accidentally mixed up two dough balls I made from these doughs, it was easy to work out which was which.

70% vs 60%

From the air, the two pizzas looked almost alike. (70% water on left, 60% water on right.)

Pizza Test: When making the pizzas, the wetter dough was noticeably more stretchy. The drier dough did stretch a little bit, but tightened up after it had been rolled. But the difference between them was most noticeable when I tried to roll out the pizzas: the drier dough was easy enough to form into a flat disc, whereas the wetter dough was too sticky to roll properly. However, the wetter dough was supple enough to be pulled out into a pizza shape without using a rolling pin. My skills as a pizzaiola are non-existent, but I still managed to form a decent-looking pizza – it had a raised outer crust (what Peter Reinhart assures me is called a cornicione), and generally looked cool. My impression from forming the pizzas is that the wetter dough was much more alive. It’s much more responsive and fun to work with. The dry dough is like Ed Miliband. It’s prim, and dull, and you want to try to like it, but it’s a struggle.

Whatchoo talking about, Willis?

My pizza-shaping skills are so refined that the differences between the two pizzas are barely perceptible to the naked eye. Ahem.

After baking, the pizzas were visibly different. The wetter dough pizza had risen more (partly because my shabby efforts in shaping it by hand meant that it was much thicker than the drier dough pizza, but partly too because it showed more oven-spring). It tasted a little bready, chewy, almost naan-like, because of its thickness. It had risen nicely, and I liked the shape of the pronounced cornicione, though I think it would have been better if I’d managed to make it thinner. The drier pizza was flatter, and because the edges were thinner, they had browned more. It had a crunchier texture, and I liked the flavour added by the slight caramelisation of the crust. This aside, the pizzas tested very similar. The major differences were in the texture and thickness.

Ed Miliband is 60% water

A picture is worth a thousand words. In this case, seven hundred of them are "Noooooo!".

Flatbread Test: As with the pizzas, the drier dough was much easier to work with. It behaved itself, held its shape, and didn’t stick. The wetter dough was much more delicate – it took a good spray of olive oil on the work surface and rolling pin before I was able to roll it into a disc. During baking, the drier dough puffed up and was more pitta-like, whereas the wetter dough was a little tighter and less puffy. As a result, the drier dough was a little more crunchy. The wet dough had a softer texture, a little like untoasted pitta. That aside, there was no great difference in taste, and only a slight difference in texture.

Dough Ball Test: The wetter dough was easier to shape into a boule than the drier dough; the extra stickiness helped when trying to seal the base of the dough balls. After proving, the wetter dough seemed to have risen a little more. It was more airy, with a little more give when you squeeze it. Both looked and tasted fine after baking, though the wetter dough had risen a little more, and had a little more airiness to it. The dry dough was a little tighter, and more claggy due to the tighter crumb. Both tasted good though, and any differences between the two doughs were pretty minor.

The Verdict

The Verdict

"Mr Waddle, you have been found guilty of crimes against hair. Also, 'Diamond Lights' was shite."

Changing the amount of water in the dough doesn’t seem to make much difference to the taste. It does, however, change the physical qualities of the dough a lot. The wetter dough, with 70% water, rose more during proving, and was stickier and more elastic during shaping. The drier dough, with 60% water, was stiffer, less adhesive, and could be rolled out more easily. Because of this, there were some interesting incidental differences in flavour between the two pizzas: the drier-dough pizza had a thinner crust, and so it caramelised more, was more crunchy, and had a more varied mouthfeel. The wetter-dough pizza had a thicker, raised crust. This tasted quite bready, which wasn’t unpleasant but didn’t seem so appropriate for a pizza. For the purposes of these side-by-side experiments, a drier dough actually has the advantage that it’s easier to make into two identical pizzas, using a rolling pin – the wetter dough is harder to shape consistently (at least with my shaping skills), as it needs to be formed by hand. But I think that if you were able to shape the wetter dough into a thinner pizza, that’d be the best of both worlds – it’d give you a crunchier raised crust, and would be easier to shape into the classic raised-crust pizza shape than the drier dough.