In Crust We Trust
Every time I look at social media, I am bombarded with pictures of pizza crust close-ups. People displaying the huge air pockets in a cross section of crust, also known as a cornicione. Don’t get me wrong, I like a good crust shot as much as anyone, but what is it that they are really showing off? Proper fermentation. For me, this is what creating the perfect dough boils down to. You can use all of the right ingredients but if your dough is not properly fermented then you’re not going to have the light and chewy crust that is so desirable. To understand just how to achieve your perfect cornicione, it is important to understand the fundamentals of dough production and a few crucial steps that should not be left out in order to create the perfect dough. They all center around fermentation: the initial bulk rise, doing an autolyse and the final rise.
What exactly is fermentation? It all starts with yeast. Whether you are using instant, fresh, active dry or a sourdough starter, the fermentation process you choose will have a huge impact on your final dough product and thus your beautiful crust. While there are over a thousand different species of yeast, commercial yeast is almost always Saccharomyces cerevisiae. Once you have added yeast to your dough the fermentation process begins. Fermentation is an anaerobic reaction where the yeast feeds on simple sugar in the absence of oxygen. It produces ethanol and other derivative chemicals. Basically, the yeast is eating the simple sugars released by the flour’s starch that has been broken down and in turn releases carbon dioxide. The carbon dioxide is what forms the tiny air bubbles in the dough. This process is highly affected by your dough’s temperature. If the dough gets too cold the yeast won’t activate and if it’s too hot it won’t survive. This is why you always hear people talking about IDT or the Ideal Dough Temperature. Not everyone’s IDT will be the same depending on what type of yeast you are using, how long you plan on bulk rising and if you do a longer cold fermentation. You can control the temperature of the dough by the temperature of the water that you add to it and plugging it into this formula:
Temperature T water = T dough x 3 – (T room + T flour +T mixer heat)
In general, the longer you ferment your dough, the more flavor you are going to get out of it. A slower fermentation creates a better gluten structure which means better bubbles in the crust due to the aid in gluten development. By rushing the process, you end up with a one-dimensional dough, in both flavor and texture. One way to save time on your overall bulk and cold fermentation is to use a pre-ferment. The two most common are a Poolish or a Biga. Simply combine flour, water and yeast and allow it to ferment at room temperature overnight. By adding this to your dough, you are getting a head start on its flavor and structure.
With pizza dough there are several ways to achieve your ideal fermentation. The first step is to incorporate an autolyse into your process. This is a step in dough making that I find a lot of people leave out, but all of the best bakers find essential. It is the step right after you have combined the flour and water (I add the yeast here too) and before you add your salt and oil. An autolyse, or rest period, is basically just letting your dough rest for 20 to 30 minutes. This allows the gluten net to strengthen and increases the dough’s extensibility. This is an important quality, not only in the dough’s ability to be stretched without ripping but also in achieving a good rise or volume. It can be the difference between having a pasty, flat crust and a bubbly, chewy one.
After the autolyse and your final mix, the next step is to do a bulk fermentation (also called a bulk rise). For my own shop, we do a five-hour bulk rise (once the dough has finished mixing, we place it in large bins at room temperature). Since we use a sourdough starter, this allows for the yeast to really kick in and start to develop the flavor and texture that I am looking for. If you are using a commercial yeast, you might want a shorter bulk fermentation. Whatever length your bulk rise is, this is the stage where the strength, flavor and structure of the dough are developed. At this stage, you want to make sure the dough stays at a consistent temperature. You can speed up or slow down the rise by either placing it in a warmer area or placing it in the walk-in. However, just like it is possible to under ferment a dough, you also want to be careful not to over extend it. If you let the bulk fermentation go too long or get too hot, the glutens in the dough begin to degrade due to increased acidity and result in a tighter, smaller crumb.
After that, we cut and ball the dough. Once the dough is balled, we let it rise another five hours outside of the walk-in before giving it a 24- to 48-hour cold rise. By giving the dough the chance to rise in the beginning, it cuts down on the time we need to pull it out before service because the yeast is already activated and proofed to the point that we want it to bake at.
Do you ever get a slice of pizza and notice that there is a huge gum line? The reason for this is improper proofing. Proofing is the final rise that the dough goes through before baking. It is a crucial step, as it helps to create those beautiful corniciones. Once your dough is ready to be pushed out into a pizza, all of the internal chemistry has been done. If you have accomplished a proper fermentation and rise, then the dough should pop in the oven.
In theory, all dough is fermented but how you choose to carry out the process will affect your final crust. Everyone has a slightly different approach to making their signature recipes, but there are a few important steps that anyone can benefit from adding into their process. Don’t be afraid to play around with a variety of methods to achieve your perfect crust.
Audrey Kelly owns Audrey Jane’s Pizza Garage in Boulder, Colorado.