Name: Pan de Cristal
Prep time: 30 min
Ingredients: 500 g strong bread flour; 525 g water; 100 g active starter; 10 g salt

About This Recipe

What is Pan de Cristal?

Pan de Cristal (also known as Spanish Glass Bread) gets its name from its beautiful open interior and crispy crust, which shatters like glass. This bread is similar to its Italian cousin, ciabatta, in many ways, but originated in a completely different location. Pan de Cristal is made from a very wet dough and baked at a high temperature to create its statement open crumb and crispy crust. The result is a chewy, crusty bread – excellent for soups, sandwiches, or just for topping with olive oil and tomatoes.

What I love about this recipe:

This recipe is simple yet advanced, all at the same time. Just four ingredients come together to create this crusty, chewy bread. Because of this dough’s incredibly high hydration (105%), it is essential to develop the gluten using coil folds, which makes the dough handling options limited, but also very hands-on and satisfying. The final crumb reveal is the most exciting part of making this recipe, as it just is not something that is seen with every bake.

All the "why's"

Strong Bread flour

Bread flour is an incredibly important element to achieving success in this recipe. Without a strong bread flour, the dough will not come together through the folding process. It will remain very wet, and will break and fall apart easily. For best results, it is important to use a bread flour with a high protein content, above 12%. I use King Arthur Bread Flour in any recipe that calls for bread flour, and especially when I make this recipe. Ultimately, you can use any strong, white bread flour available to you.

If you absolutely cannot access a good quality bread flour, it is possible to still make this recipe by reducing the amount of water to match what your flour can handle and adding a couple of tablespoons of vital wheat gluten to the dough. While these two things will make this recipe possible for you, they will not lend quite the same results.

High hydration

High hydration simply means (by my own definition) “very wet dough.” The hydration of this recipe is 105%, meaning it contains more water, by weight, than flour. Read more about dough hydration here. The hydration of this dough has everything to do with the final outcome and is one major party responsible for the open and chewy interior of this bread.

Gluten development

Gluten in this recipe is developed through a series of intervaled coil folds. Coil folds, which are most suitable for wet doughs, are the chosen method for this recipe due to its high hydration. Each fold develops and changes the dough even further, resulting in a strong dough that doesn’t fall apart and is able to puff up nicely in the oven. Read more about gluten here.

Bulk Fermentation

After the folding process is complete, this dough is left to double in size. In reality, bulk fermentation is flexible, meaning you could shape and bake this loaf after a 50% size increase. I prefer to push my dough as far as possible, as I think the final texture of the bread is much better – becoming lighter and airier with time. This means at least double in size, sometimes farther.

Cold Bulk fermentation

The refrigeration step of this recipe is optional, but it does several things to help the dough. First, as with refrigeration in any recipe, it sets the flavors, creating a deeper sourdough flavor. If you do not prefer any hint of sour in your bread, do not cold ferment your dough. A refrigeration step also makes the baking schedule more flexible, meaning there is no baking dough too late in the evening and waiting for it to cool before you can go to bed. But, for this dough specifically, it creates a more even crumb. A warm, room temperature dough popped into a hot oven will spring up like pita bread, and you may end up with a huge hole in the top of the bread. Chilling the dough can help prevent this from happening.

Baking Method: Steam

The steam is crucial to the first few minutes of baking these loaves. Steam delays the formation of crust, allowing the Pan de Cristal to expand to its full potential before the outside forms. In addition, the steam will help improve the color and texture of the crust, helping contribute to the golden-brown color and thin, crispy exterior.

I chose to use a pan of boiling water for simplicity, and because I do not own lava rocks. The high hydration of the dough works together with the steam to keep the crust thin and crispy, so the most perfect steaming method is not required. But, if you have lava rocks, pouring boiling water over them as your steam option is really the best choice.

Baking Method: temperature

I played around with a lot of temperatures when baking this bread, and finally settled on a combination of two. 475 F, combined with the addition of steam, helps promote the best oven spring. You can watch these loaves literally pop up in the oven in the first ten minutes of baking! After that, 400 F for the remainder of the time perfectly cooks the loaves through without over-browning.

Suggested Baking Timeline

8 AM (Day 1)

+Mix the dough

8:05 AM - 11 AM (Day 1)

+Strengthen the dough

11 AM (Day 1)

+Finish bulk fermenting the dough

5-9 PM (Day 1)

+Transfer to refrigerator

8 AM (Day 2)

+ Preheat oven to 475 F

+ Boil water

8:30 AM (Day 2)

+ Shape the dough

+ Bake and enjoy!

FAQs

Can I knead this dough in my stand mixer?

This is going to depend on your mixer. For a KitchenAid, I would recommend using the paddle attachment and only using the mixer to combine the ingredients and get a thorough mix on the dough up front. This will help kickstart gluten development. If you own a mixer like an Ankarsrum, you may be able to work the dough more efficiently, but I have not tested this.

Can I speed up fermentation using a proofer or warm oven?

You can absolutely use a proofer or warm oven to speed up fermentation, though you will need to keep a couple things in mind. First, you may want to reduce time in between folds or perform your folds at room temperature before placing the dough in your warm area. This is because fermentation occurs faster in a warm area, and it is important to get the gluten developed as much as possible earlier in the fermentation process so that the dough can ferment (hold in air) more efficiently. In you choose to reduce time between folds, fold every 20-30 minutes, instead of every 45. Also, I do recommend placing your dough in the fridge before baking, even if just for 30-60 minutes. Why? Room temperature dough will have a more substantial oven spring for this recipe. In some cases, such as when making baguettes, this is desired. But, in a recipe like this one, the effects can be negative. Especially if your Pan de Cristal dough is warm from the proofer upon entering the oven, it will spring up quickly and beautifully on the outside, but it may leave you with one large gaping hole on the inside. Cooling the dough in the refrigerator first will eliminate this potential problem.

Can you convert this recipe to volume measurements?

For this recipe, I have decided not to convert my ingredients to volume. The exact weights of each of the four ingredients in this recipe are very specific and intentional, and volume simply cannot be as accurate, leading to inconsistent results.

Pan de Cristal

Recipe by Caitlin VincentCourse: Lunch, Dinner, Snack, SideCuisine: SpanishDifficulty: Advanced

Prep time

minutes

Resting Time

hours

Baking Time

minutes

Yield

loaves

Pan de Cristal (also known as Spanish Glass Bread) gets its name from its open crumb/interior. This bread is similar to its Italian cousin, ciabatta, in many ways. Featuring a high hydration (very wet) dough, chewy interior, and crusty outside, this loaf is absolutely an advanced working loaf that will yield incredible results.

Ingredients

500 g strong bread flour
525 g water
100 g active starter
10 g salt

Directions

Mix together all ingredients (any order you choose).
Let the dough rest for 45 minutes, then begin the strengthening process.
Strengthen the dough: Perform four sets of coil folds, 45 minutes apart. Lift the dough up from the middle, and allow it to fall over itself. Repeat 1-2 times in each cardinal direction. (To hear my commentary on this, see 1:05 in the video.)
Bulk ferment: Let the dough rise until it has doubled in size * (see note).
Shape and bake the dough right away, or refrigerate 8-16 hours.
Preheat your oven to 475 F (Optionally, preheat a baking stone. I do not use one in this recipe.) Set your oven racks so that one is on top and another is on the bottom.
Shape the dough: dump the dough out onto a floured counter and divide into four equal sections. Transfer the dough to parchment paper * (see note).
Boil some water in a tea kettle or on the stovetop.
Transfer the boiling water to a water-safe loaf pan, and place on the top rack of your preheated oven.
Transfer your loaves to the back side of a 9X13 baking sheet and place on the bottom oven rack. Or, transfer the loaves onto your preheated baking stone.
I can fit two at a time in my oven * (see note). Keep the other two loaves in the refrigerator until ready to bake.
Bake at 475 for 10 minutes.
After 10 minutes, remove the steam and baking sheet * (see note). Transfer the loaves to the top oven rack.
Reduce the oven temperature to 400 F and bake 20 more minutes, until golden and the internal temperature registers at least 190 F. Add 5-10 more minutes if you want a darker crust.
Cool on a cooling rack 20-30 minutes before slicing.
Enjoy!
How to store: Store in a sealed bag on the counter up to seven days.
To reheat: Toast in a toaster oven or air fryer until warmed through and crispy. DO NOT microwave.

Watch the Video

Notes

Bulk ferment: It takes my dough about 6 hours to double on the counter at room temperature (about 70 F). You can also use a heating aid here (ex - proofer or dough mat).
Shaping: This dough is typically heavily floured, due to its high hydration. I do not find this necessary. I simply wet my hands and bench scraper. You can do as you like for this step.
Baking: You can bake all four loaves at once, if your oven will allow it. I was able to fit two 9X13 baking sheets in the oven, one on the bottom rack and the other on the top rack beside my loaf pan of boiling water. You will need to add at least 5 minutes to the initial baking time (at 475 F, until the loaves are fully puffed up and the outside is partially cooked), then remove the steam (and both baking sheets) and transfer all the loaves to the top rack. Reduce the oven temperature to 400 F and bake the remaining 20 minutes, or until the internal temperature is 190 F and the loaves are browned to your liking.
Baking: Removing the stone or baking sheet is absolutely necessary, as I have found the bottom of the loaves will not brown properly if it is not removed. This is because the baking stone or sheet redistributes the heat (similar to what would happen if you placed one under a Dutch oven while making a country loaf of sourdough, which I do to prevent burning) and actually prevents the bottom from browning. I even struggled with even browning when using a preheated baking stone or sheet in the middle of my oven the entire time. I truly prefer this baking method best for this bread.