How do I extend the rise time of my bread?
Factors affecting rise time
Years ago I saw "The Magic Christian", a marvelous, if somewhat cynical, comedy starring Peter Sellers as Sir Guy Grand, an insanely rich eccentric British member of the aristocracy, and Ringo Starr as Youngman Grand, a street person Sir Guy adopted to be his heir. At one point, Sir Guy and Youngman Grand joined a duck hunt with a group of aristocratic English hunters who were obsessing about their shotguns and the value of a "quick, clean kill". Without giving away too much, Sir Guy and Youngman redefined the term "quick, clean kill" for the hunters.
Similarly, sourdough bakers obsess about a "long, slow rise" and for good reasons. We want to give the lactobacillus time to create the sourdough taste that we are working for, to give the bacteria time to create the acidity that helps preserve the bread and unlock some of the nutrients in the flour that would otherwise be unavailable.
There is reason to believe that we'll do almost anything to achieve our goal.
The rest of this discussion assumes that you understand that there are two components to a sourdough starter. If you aren't fully up to speed on what sourdough is, and how it works, you might want to check out our What is sourdough tutorial.
In any case, here are some strategies that work...
You can start by adjusting your recipe to use less starter. I have seen the same recipe in cookbooks using from 1/4 cup up to 4 cups of starter. The rise time varied from 16 to 2 hours. A two hour rise just doesn't give the bread time to acquire a good sourdough taste. However, there are times when ya gotta do what you gotta do - like when unexpected company is about to come over for dinner. Increasing the amount of starter and rising the bread in two hours, assuming you have active starter that's ready for use, will put good bread on the table. You'll know, and your family will know, that the bread isn't up to your usual standards, but your company probably won't. (And if they do notice, tell 'em that what they got is what unexpected company gets.)
Of course, adjusting the amount of starter means changing the amount of flour and water in the recipe to keep the consistency of the dough right.
When I first moved to Colorado, and moved from sea level to 7,703 feet above sea level, I had to reconsider baking. Bread just rose too fast, and too far. The Colorado Extension service suggests controlling bread by having it go through an additional rise. So, I coped by punching down the bread. In working on the 100 percent Whole Wheat recipe and the variations on the 100% whole wheat sourdough bread recipe, I found that the more rises the bread went through, the more pronounced the sourdough taste becomes. Punching down, or deflating, the dough gave the lactobacillus more time to develop the bread's taste. A side benefit is that I liked the crumb definition better.
For years bakers have retarded - or slowed - their dough by refrigerating it. This is very convenient for a professional baker who doesn't want to work beastly hours. The baker can prepare the dough the day before, let it rise in the refrigerator, and then bake it the next day. Home bakers do this also, because otherwise baking could interfere with their work schedule.
However, it is worth noting that commercial bakers yeast has been bred to work at lower temperatures than sourdough. The reports of the effectiveness of retarding sourdough based dough are variable, perhaps because different people have different sourdough cultures. Also, with regards to flavor development, the sourdough baker wants to speed up the lactobacillus with respect to the yeast, so the flavor development will be acceptable by the time the bread has risen.
There are many anecdotal reports that chilling the dough does this.
But there is evidence to suggest that this just isn't so. In one of his recent newsletters, Dr. Ed Wood commented that he had retarded some dough and the flavor was not what he expected. In a later test, he elevated the temperature of the dough. And the bread was great. This had him scratching his head, as it was the reverse of what he was expecting.
More evidence is found on page 53 of Alan Scot and Dan Wing's book, "The Bread Builders". Two charts show the activity of L. san-francisensis and C. milleri at different temperatures, plotting how long it takes the organisms to double. I've combined the two charts into one, and included it below, so a lower number means the organism is reproducing faster.
It is interesting to note that the lactobacillus is reproducing faster than the yeast at all temperatures. However, the difference in their metabolic rates remains pretty constant at lower temperatures. However, at higher temperatures the yeast component slows markedly in comparison to the lactobacillus. This begins around 90F. The down side if this is that keeping a culture much above 90 for too long can kill the yeast.
Scott and Wing suggest that the optimum temperature for the lactobacillus fermentation - as opposed to reproduction - is around 93F or 34C. They also comment that the optimum temperature for yeast is around 86F or 30C.
However, there is a large body of anecdotal reports that suggests that a refrigerated dough becomes more sour than a non-refrigerated dough, it is possible that different cultures may respond differently. It is also possible that some people observe what they want to observe.
Some recent discussions in the Bread Baker's Guild mailing list may have clarified some of the ambiguity. When a home baker chills dough, it is usually at home refrigerator temperatures, around 34 to 38F. When a commercial baker retards their dough, it is at temperatures ranging from 45 to 68F, depending on the bakers needs. This difference is the difference between a dough that is virtually frozen in time and a dough that's slowly rising and developing. Craig Ponsford said he cannot make an acceptably sour bread without retarding it.
As with so many other topics, the more world class bakers you talk to, the more conflicting information you get. It makes it hard for us mere mortals to know what to do. The best answer is to try experiments and see what works for you. Remember, you probably don't have the same strains of bacteria and yeast in your starter that Craig Ponsford, Dr. Wood, Alan Scot, Dan Wing or I have. Part of learning to bake with sourdough is learning what works with your culture no matter what an expert tells you - you need to become the expert on how your culture behaves.
If you want to experiment with slow rises for flavor development, I suggest looking around for a cheap, but working, refrigerator or freezer. You can find them in garage sales, local shopper papers, and sometimes appliance repair shops will give away a customer's old refrigerator when the customer buys a new one - giving it away is better than paying a disposal fee.
Put a homebrewers thermostat on your "new" refrigerator or freezer. These run less than $50 and allow you to set the refrigerator or freezer's temperature where you want it. Let's say 68F. They hold the temperatures quite accurately. At these higher than home refrigerator temperatures, I think you'll get the results you wanted. If not, you'll find more information in the Retarding Dough For Flavor Enhancement and Process Control page.