The Power of Protein

Raymond Calvel, in his much consulted book The Taste of Bread, is very precise in pointing out that "the quality of a flour can only be determined by test baking."  However, he does go on to say that "the baking quality of a flour is related to the quality and quantity of proteins and the gluten that derives from them."  Calvel was perhaps the first to go beyond the simple protein percentage (quantity) and start to look at how that protein is composed (quality) and thus its affect on the finished dough.

This protein "quality," in the sense that it matters to the baker, can be determined physiologically by the relative ratios of gliadin and glutinen found in a particular wheat flour. Gliadin and glutinen are the protein sub-units found almost exclusively in wheat flour and, through mixing, develop to become the gluten network that allows bread dough to become cohesive and trap the gas produced by fermentation allowing the dough to rise. Gliandin, owing to its relatively small size, contributes extensibility while glutinen contributes elasticity. A good bread dough needs to exhibit the proper balance of these two traits. Too much or too little of one or the other makes the dough difficult to work with and will yield in unsatisfactory results.

In practical terms, determining the ratio of gliadin and glutinen is not feasible for the miller attempting to mill a high-quality flour, nor for the baker who wants to know the characteristics of the flour that has just been delivered to her bakery. However, the characteristics of a flour's  protein, and its influence upon the performance of a dough mixed from it, are easily measured and quantified using either the farinograph or the alveograph. The challenge here, though, is that these methods of analysis are looking at the finished product. Therefore, the real job for the miller is selecting wheat that will yield flour with the appropriate performance characteristics. While a wheat's protein content is easily determined, it is only a rough estimate of the performance of the flour that can be made from it.

I asked Joe Lindley of Lindley Mills in Graham, NC, about this challenge of selecting wheat that will yield a flour with the desired characteristics to meet his customer's needs. He told me, not surprisingly, that they rely extensively on the farinograph of the finished flour. Joe said it used to be that prior to perhaps five years ago the protein percentage of the incoming wheat gave you a pretty good indication of what the performance characteristics of the finished flour were going to be. In his estimation (and he readily admits that this is an unscientific observation), over the past five years the protein content on the incoming wheat and the farinograph characteristics of its flour have ceased to correlate—or correlate far less than they once did. Which, today, means they put far more emphasis on the farinograph characteristics of the finished flour and, perhaps, somewhat less emphasis on the actual protein percentage. Joe said he would much rather see the farinograph match up with what the customer is expecting performance-wise than strictly matching a protein spec.

Later, I was speaking to Tom Crell, Technical Services Representative at Horizon Milling in Albany, NY, about this subject of protein and performance, and he immediately said: "You have to remember, it's protein quality, not protein quantity [There's that phrase again], and protein quality is directly related to the environmental conditions and how these environmental conditions affect the wheat kernel determines how the mill goes about extracting the flour from the kernel." The developing wheat plant is subjected to varying amounts of rain and sun; soil conditions differ from location to location; planting time will differ from location to location and year to year. The ultimate outcome of these variables is seen in the wheat kernels with a whole range of physical characteristics: slender or fat, plump or shriveled, drier or wetter, etc. These kernel characteristics ultimately determine how the miller is going to mill and thus how the flour is going to perform.

Over the past year, Tom told me he has seen a shift among many of his bakery customers away from a hard requirement for a certain protein specification to a realization that the same if not better results can be had from flours of lower protein. Tom told me that for years, no matter what he said to many of his customers they wouldn't budge on their protein requirements. Then, starting about a year ago, the price of flour climbed to reach extremely high levels, and suddenly everyone was looking for ways to save money. Since flour price is largely determined by protein content, people were suddenly willing to look at lower protein content flours to potentially cut costs. Tom told me that almost everyone who switched was able to make their products just as well with lower-protein flours, and many have not switched back even with the return of lower flour prices.  They are still getting the performance out of the flour that they need, but they are seeing that they can get that performance with flour from lower protein content.

One bakery that made just such switch when prices were high last year was Zingerman's Bakehouse in Ann Arbor, MI. For most of their first 16 years, they were using a spring wheat flour with a 12.7% protein. Once the price of flour started to rise, they, like many other bakeries, started to look for savings. They presumed that if they could switch to a winter wheat flour with 11.7% protein and make the change transparent to their customers, then they could save a considerable amount of money during a very uncertain time in the flour market.  Not only were they able to achieve those goals, "It made us better bakers," Frank Carollo, co-managing partner and founder of the Bakehouse, told me when I was there a month ago. 

But what the precise differences were and how the old flour performed relative to the new flour was hard to recall. So we decided to try an experiment and run both flours through the exact same process and see how they differed. 

Frank and Stewart Marley, the bread production manager at the Bakehouse, and I set out to make Zingerman's Rustic Italian Loaf with their current flour (11.7% protein) and their former flour (12.7% protein).  Everything else was left the same: absorption, mix time, fermentation time, etc. When Zingerman's made the switch, their goal was to produce exactly the same finished bread, and to do so they had to adjust their process. Conversely, if you were looking to accentuate the characteristics of a different flour you would make adjustments in your process. But for us, we simply wanted to see the effects of the different flours.

The Rustic Italian Loaf uses a poolish (equal parts of flour and water fermented for 8 hours) as a preferment, and right away we saw a difference in the two poolishes—and one that would show up repeatedly throughout: the poolish made with the higher protein flour had risen higher (perhaps 25% higher). The obvious conclusion was the extra strength of the preferment (even at 100% hydration) allowed for more gas retention and thus higher rise.

Once all the ingredients were in the mixer and mixed to the required development, not unsurprisingly, the higher protein dough was stronger, somewhat elastic and drier feeling. A validation of what one would expect. The lower protein dough was more extensible, slightly tacky and "weaker" feeling—but not in an inappropriate sense.

Next the doughs were placed in bins and allowed a bulk ferment for four hours. After the first three hours, the dough mixed from the higher protein flour had risen further, and by the end of the fermentation, had considerably more volume than the lower protein flour. It also continued to feel "stronger" and decided less extensible than the lower protein dough. We also felt that the higher protein flour dough had a "reddish" hue to it whereas the lower protein dough had a more yellowish/creamy color to it. Generally a creamier color is associated with doughs that have received less mix, but in this case both doughs received the same amount of mix, so it is difficult to come up with a justification for this difference.

Once the fermented doughs were placed on the shaping table, again the differences were striking but not out of line with what one would expect: the higher protein flour dough "sat" higher on the shaping table and was stronger and drier, while the lower-protein flour showed generally "weaker" characteristics. They shaped the higher protein dough first. Upon switching to the lower protein dough, Frank noted that with the first couple of loaves he shaped, he tore the skin of the shaped dough slightly. He said he hadn't accommodated for the slightly weaker nature of the dough, but upon "adjusting" was able to shape without tearing. The same would hold true for a weaker dough on an automated line where most high-quality equipment will allow you to reduce the stress on the dough to accommodate changes in dough strength.

The final proof for our two doughs was performed on covered racks next to the oven.  At the point just prior to the bakers loading the oven, they wanted to load the lower protein loaves first (even though they were mixed second and thus had less floor time), as they felt they were fully proofed. I had to jump in to keep the "experiment" on track and, against their better judgment, had them load the higher protein loaves first, even though they felt the others were further along. Not that I had better judgment (far from it), but we weren't optimizing the bake but comparing only one variable. The higher-protein loaves had proofed higher and were still considerably stronger feeling than their lower-protein neighbors, which, in addition to not having as good proof volume, had spread out slightly more. They had the appearance of being further along in the proof than the higher-protein loaves. In the oven, the higher-protein loaves got great oven spring and the cuts opened beautifully. The lower-protein loaves required slightly gentler handling so as not to de-gas, but once in the oven they got all of the oven spring that the first group had, and once on the rack had all the volume of the higher-protein loaves. Also, once on the rack, we noticed a continuation of the color differences first seen in the doughs with the higher-protein loaves having a reddish-brown coloring to them and the lower-protein loaves being a browner/creamier brown (a browner-browner, if you will).

The next day we sliced the loaves open and found a more open crumb structure in the lower-protein loaves and a creamier color, whereas the higher-protein loaves had a tighter crumb and were more white-ish in color. We really could detect no flavor differences between the two.

Zingerman's, like many bakeries, recently had a goal of switching flours to achieve a certain result: cut their flour costs while not changing their finished product. They found that they need not rely solely on the protein content of the flour to determine which types of bread they could make but found, instead, that while this content was a guide, the overall protein quality dictated the process (absorption, mix time, handling, and baking) and that by changing their process to meet the characteristics of the dough mixed from this new flour they could achieve their goals. Conversely, should a bakery want to make a fundamental change to a product, they can either adjust their process to exploit a characteristic of their current flour or switch flours altogether to take advantage of a particular flour's protein characteristics.
Bread of the Month: Zingerman's Bakehouse Rustic Italian

Formula

Weight

#

%

Flour (11.7% protein)

46.2

#

100.0%

Water

26.21

#

56.7%

Poolish

9.83

#

21.3%

Yeast

0.05

#

0.1%

Salt

1.05

#

2.3%

Total

83.34

#

Poolish

Flour

5

#

100.0%

Water

5

#

100.0%

Yeast

0.077

#

1.5%

Total

10.077

#

Overall Formula

Flour

51.2

#

100.0%

Water

31.21

#

61.0%

Salt

1.05

#

2.1%

Yeast

0.127

#

0.2%

Total

83.587

#

(1) Mix the polish ingredients and allow to ferment for 8 hours or until fully developed.

(2) Mix all the ingredients for the dough including the polish to full development. Target temperature of the final dough is 78 degrees F.

(3) Allow the dough to bulk ferment for 4 hours.

(4) Scale at 1.2# for small loaves and 1.75# for the larger loaves and pre-shape gently into a round. Allow to rest for approx 45 minutes.

(5) Shape and allow for final proof of around 1 hour.

(6) bake at 430 degrees F with light steam in the beginning.