The importance of proofing bread correctly.
The proofing step is often seen as an invariable operation which is inherently reliable by itself. This statement cannot be more inaccurate. The proofer operation relies on several factors to successfully provide the intended effect on the dough. Inside the proofer, the dough is expected to expand several times its initial size, develop flavors and aromas, and ultimately deliver a product that properly expands and sets its porous structure in the oven.

Maintaining the consistency of the final proofing environment throughout the year by utilizing relative humidity and temperature measuring instruments is the proven method to avoid numerous yield-stealing process problems in the commercial bakery.

Standard proofing conditions

Whether it is cold or hot, dry or humid, bakeries should always focus on maintaining standard operating conditions when it comes to the proofing process. The following tables summarizes the optimum conditions for high-speed proofing of pan bread, buns and rolls.

Variable Target value
Proofing temperature (proof box internal temperature) 105–115°F (40–46°C)
Proofing humidity 80–90%
Proofing time 55–65 min
Initial dough temperature 81°F (27°C)
Final dough temperature (at proof box exit) 92–97°F (33–36°C)
Temperature increase during proofing 11–16°F (6–9°C)

Strategies used to consistently achieve such conditions often involve the design of proper HVAC equipment. By using properly designed and sized air conditioning systems, industrial bakers have an opportunity to reduce the incidence of ambient factors which affect the overall plant’s atmospheric conditions. Such systems adjust the humidity, cleanliness and temperature of incoming air so that it has the desired characteristics that bakers need in order to maintain stable plant conditions.

Bakers who cannot afford robust HVAC systems, must be prepared to deal with inevitable fluctuations in the humidity and temperature of atmospheric air being injected into the bakery and exhausted into a facility’s surroundings.

Proofing under hot and humid conditions

As spring becomes summer, increases in local humidity and temperature become a very significant variable to the ability of high-speed bakeries to bake a consistent product. On the other hand, the ability to call in vendors to perform process troubleshooting is not possible during the Covid-19 sheltering situation.

Effects of excessively hot and humid conditions:

  • High humidity in the proof box will directly contribute to structural weakness due to moisture saturation of the crust of the roll or bread. This saturation will allow the resulting CO2 being produced from yeast fermentation to more easily rupture the cell wall. This results in weakness, requiring more dough strengthener on a formula basis.
  • A proof box that is saturated with water vapor will cause blisters and a tough crust to form, and can cause dark spots from sugars leeching to the product’s surface.
  • High humidity will reduce pan glaze life and increase dough stickup resulting in damaged product or line stoppages.
  • High humidity will increase pan flow and will affect the healthy bold look to bread and rolls, and may increase gluten use to resolve.
  • Warmer dough temperatures will directly affect the exit temperature of the product from the oven, increasing bake loss, and forcing managers to slightly increase scaling weight, hence sacrificing yield of pieces per dough batch.
  • Warm doughs frequently usually require lower absorption levels  due to the weakness from uncontrolled cell expansion.
  • The rate of enzyme activity doubles for every 18°F rise (a delta of about 10°C). So, a 5°F increase over the standard temperature may result in a 30% increase in this rate of detrimental activity on structure integrity.
  • Excessive volume will result that can contribute to damaged product at the packaging line.

Production of low scaling weight bread

Maintaining optimum proofing conditions is particularly critical when it comes to producing low scaling weight (or high specific volume) pan bread. Low scaling weight bread is starting to become widespread and has attracted the interest of many wholesale bakeries to due its market price competitiveness.

Low scaling weight means depositing less than 0.12 ounces of dough per cubic inch of pan cavity (about 0.2 g/cm3). Producing pan bread with a specific volume (i.e. volume of finished product divided by scaling weight) of 5.0 cm3/g is not the same as producing a 7.5 bread.

Think of baking both the 5.0 and 7.5 sandwich breads using the same pan. The 7.5 bread has to properly expand during proofing and baking to fully fill the volume of the pan with a lower scaling weight (that means using less amount of dough!). That is kind of unfair, right? The 7.5 bread must support greater elongation stresses on the dough structure than the 5.0 bread and still preserve the gas bubble stability and crumb structure as any other bread does.

A low scaling weight bread must be properly formulated; meaning the use of higher amounts of oxidizing agents, strengthening enzymes and vital wheat gluten. Here, a reliable and consistent proofing process becomes an essential part of the successful production of highly aerated bread.

A closer look at proofing of low scaling weight bread during summer days

When dough temperatures at the proof box exit exceed the range of 92–97°F (33–36°C), the dough becomes less viscous (i.e. more fluid) and the gluten structure becomes more extensible. These conditions imply that the dough is more susceptible to cell rupture or weakness, increasing the need for dough strengtheners and gluten use. This situation can easily be checked by running a mixolab test and monitoring the resistance to deformation of the formulated dough in the Gluten+ phase.

In the same higher temperature scenario, naturally occurring enzymes in flour, plus enzymes added as part of dough conditioner mixes, will become more active as the internal temperature of the dough is increased. Protease, xylanase, alpha- and beta-amylases will all increase in their activity rates directly affecting the structure. This causes weakness issues – increasing the requirements for oxidizing agents and vital wheat gluten so that absorption levels are not decreased.

In the worst cases, enzymatic activity can get so high that it leads to systemic breakdown of the dough, which is no longer capable of keeping up with gas production and expansion. This leads to considerable yield loss as many dough pieces may need to be discarded prior to baking, or simply baked without meeting finished product volume specifications (increasing waste).

Having even basic test measurement instruments, and knowing how to use them is essential for maintaining production quality and high yields to profitably satisfy the current production demands of grocery, take out/delivery, and the re-opening of restaurant, hotel and caterer clientele your bakery serves.

Monitoring conditions during summer

Final proofing can be profiled with a combination of a relative humidity and temperature recording device By using this device, bakers can accurately track humidity and temperatures (both product and ambient) inside the proof box. This sensor and data recording device can be used by any bakery to validate equipment performance, and recall that data at any time for analysis, realizing a minimization of process variations, an increase in production yields and a reduction of waste towards greater profitability for the business.

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