Importance of Temperature in Baking Sourdough Bread

from https://www.theperfectloaf.com/

When I first started baking, I didn’t quite grasp how important temperature is in the bread-making process. I always like to say: treat temperature as an ingredient. What I mean by that, practically, is that if one day you mix with water that is 70°F (21°C) and then a week later mix with water that is 80°F (26°C), you will get drastically different outcomes. Temperature determines the amount of fermentation activity you’ll see. Lower temperatures generally mean less activity, therefore things will take longer. Higher temperatures generally mean more activity, therefore things will take less time. Working at an ideal temperature will ensure both consistency in your bread baking and that you’ll get the results that you want in terms of flavor, rise, texture–well, everything.

Final Dough Temperature (FDT)

The final dough temperature (FDT) is the temperature of the dough right after mixing all of the ingredients together. Naturally, each component (levain, the flour, the water, and the ambient environment) has a temperature. While most of these are out of our control, we can easily adjust the water temperature, and adjusting this temperature enables us to change the FDT of the entire dough to meet whatever the recipe calls for.

Let’s look at an example. Here, we will determine what our water temperature needs to be in order to meet an FDT of 78°F (25°C):

Ingredient	Measured Temperature
Levain	75°F (24°C)
Flour	70°F (21°C)
Room Temperature	75°F (24°C)

WaterTemp = (FDT x 4) - (LevainTemp + FlourTemp + AmbientTemp)
WaterTemp = (78 x 4) - (75 + 70 + 75)
WaterTemp = 92°F

We need to warm our water to 92°F (33°C) so at the end of our mix, our final dough temperature will be 78°F (25°C).

Because temperature is one of the main contributors to vigorous fermentation, it’s key that we maintain a sufficiently high, and stable, dough temperature through the entire baking process. Of course, this does become more difficult when ambient temperatures begin to drop (hey, winter!)—and sometimes we don’t even realize it’s happening.

Maintaining Dough Temperature

There are proofer that you can buy and set to the desired temperature. Or try keeping the sourdough on top of the refrigerator, expecially in winter.

During the summer, high temperatures can lead to sticky, excessively gassy, and eventually, over-proofed dough—sometimes without us even realizing why.

Once summer temperatures set in, and I notice my dough either fermenting faster or failing to rise in the oven as it once did in the cooler months, I'll focus on the following three things first.

1. Use ice-cold water when mixing in summer

Using cold water during mixing is my number one method for combating the heat when baking sourdough bread in the summer. While this might seem like an obvious first step, it's always my first approach to quickly cooling my dough. I keep a large bottle of water in the fridge and grab this when mixing.

Pour some of the cold water in your mixing bowl when on the scale, then combine with some room temperature water until the temperature is a few degrees below your desired dough temperature (DDT).

2. Keep sourdough starter mild and use before overly ripe

In the summer, keeping your sourdough starter mild and in control is of utmost importance. Fermentation is the cornerstone of great sourdough bread, and it all begins with your sourdough starter. In my experience, using a sourdough starter that's overly acidic means the dough will be extra active and, assuming other factors, can lead to a final loaf that's extra sour tasting with reduced leavening capacity. The greatest risk here, though, is that the dough will have too active of a fermentation rate and lead to over-proofing.

3. Reduce pre-fermented flour percentage

The amount of pre-fermented flour—typically a levain here on this site—is the jumping-off point for any recipe. It's the inoculant for a dough, the small bit of yeast and bacteria added to raw flour and water to start fermentation. The larger the mass of this levain or sourdough starter, the faster the dough will ferment.

Think about it this way: the larger the preferment, the higher the number of yeast and bacteria microbes we add to our dough. The more microbes, the higher the fermentation rate.

Adjusting this part of the recipe does affect the formula you're following, though, and it should only be done after other measures have first been attempted.

Put your bulk fermentation container in the refrigerator

To cool the dough at the end of mixing and before the first set of stretches and folds, place your covered bulk fermentation container into the refrigerator for 15 to 30 minutes. This isn't enough time to fully chill the dough, but it's enough to cool the container and take the edge off. Be sure to keep an eye on the dough during this time so it doesn't go in the other direction and dramatically cool.

FAQ

Why does my dough feel sticky in the summer?
It might be fermenting faster than you expect due to increased ambient temperatures, and subsequently, an increased final dough temperature.

Why does my dough overproof in the summer?
Warmer temperatures mean increased bacteria and yeast fermentation activity. With sourdough, an excessively acidic dough resulting from increased fermentation will degrade gluten structure and lead to more spreading in the oven, less rise, and a potentially more sour flavor.