Tortgua rum cake
Resting, proofing and baking times are all factors to consider when choosing a leavener.
Tortuga Rum Cake Co.

Timing is key

Chemical leavening involves the combining of an acid with a base, which when activated, produces carbon dioxide. Sodium bicarbonate, also known as baking soda, is typically the base; however, potassium bicarbonate is increasingly being used to assist with total sodium reduction.

“It is key to consider the process and when the gas should be released,” Ms. Briggs said. “The bicarbonate functions only as a gas source. It is the acidic components that control the rate at which the gas is released.”

In commercial baking, the base and acid can be blended individually with other dry ingredients or together in the form of a leavening system. The latter is also known as baking powder.

There are three basic categories of acidic components: fast-acting, time-delayed and heat-triggered. Selection depends on the final product, the process and its intended use.

“Fast-acting systems react during mixing and are responsible for early rise in the oven,” said Barbara Bufe Heidolph, director of technical service and development-bakery, Innophos. “They also help establish cell structure for the crumb.”

This group of fast-acting leaveners includes monocalcium phosphate (MCP), cream of tartar and various organic acids such as citric, fumaric and malic.

Time-delayed leavening systems, as the name implies, have a slower reaction period and make sense for more complex commercial processes. If the batter is going to have a prolonged hold time between mix and bake, then a heat-activated leavening acid is best for consistent performance and larger volume.

Selection should be based on the processing time, including mixing, depositing and forming, Ms. Heidolph said. In most cases, it is best to select the earliest reaction possible without compromising the dough or batter.

“These leavening agents have controlled release, which is predominantly related to time, but temperature can also be a factor,” she added.

This group includes the family of sodium acid pyrophosphates (SAPP) and calcium acid pyrophosphates (CAPP). The SAPP products typically include a number to indicate the volume of carbon dioxide produced during a specific time frame.

“For instance, with SAPP 45, approximately 45% of the total carbon dioxide is released in the first two to eight minutes,” Ms. Heidolph said. “For SAPP 28, that figure is 28%. The higher the number, the faster the reaction.”

The third category involves heat activation. This group includes sodium aluminum phosphate (SALP), sodium aluminum sulfate (SAS) and dicalcium phosphate dehydrate (DCPD).

“With heat-triggered leavening systems, the majority of the reaction takes place once a specific temperature of activation is reached,” Ms. Heidolph said. “The majority of leavening occurs after the batter or dough reaches a temperature greater than 100°F and generally is completed when 140°F is reached. Heat-triggered leavening agents provide the ultimate tolerance needed for long process times.”

Nita Livvix, director of research and development, Clabber Girl, said bakers must look at the formula and decide when the gas release needs to take place.

“Often a combination of both gas release for air cell development and a gas release with heat are optimal for a premium baked product,” Ms. Livvix said.

Gassing rates, usually referred to as dough rate of reaction (DRR), are measured by very specific instruments that quantify the percent of carbon dioxide produced over time, said Paul Bright, innovation manager, AB Mauri North America.

“With this understanding,” he said, “the chemical leavening formulator can design a system that can work well for a diverse range of applications, including warm tortilla doughs and cold batters, all while achieving the desired end-product attributes the consumer is looking for.”