Sodium Acid Pyrophosphate (SAPP)2019-04-10T14:35:46-07:00

Sodium acid pyrophosphate (SAPP) is a leavening acid commonly found in baked goods.

Sodium Acid Pyrophosphate (SAPP)

Also known as disodium diphosphate

What is Sodium Acid Pyrophosphate (SAPP)?

The leavening acid, sodium acid pyrophosphate (SAPP) is an important component of double acting baking powder as well as self rising flour. SAPP reacts in stages and is desirable in baking applications for its slow action.

Properties of Sodium Acid Pyrophosphate:1

  • Chemical formula: Na2H2P2O7
  • Molecular Weight: 221.94
  • White crystalline powder or granules
  • Soluble in water

Initially, when moisture is added to form a dough, SAPP reacts with baking soda (sodium bicarbonate) to produce carbon dioxide gas. In fact, 22-40% of gas is released during this initial two minute mix. The remaining gas, over 50%, is released when heat is applied during the baking process.2


In the eighteenth century and earlier, bakers relied upon yeast to leaven all baked goods. However, using yeast for leavening baked goods was tedious and bakers began to explore the use of chemical leavening systems. In 1846, baking soda was discovered as a leavening agent and that led to further discoveries of acids to react with baking soda, such as SAPP.3

Commercially, sodium acid pyrophosphate was introduced into baking powder blends towards the end of the nineteenth century.3 SAPP is a preferred leavening acid because it is less expensive and stronger than other leavening acids introduced previously.


Leavening acids provide air and volume to the baked good structure, but also affect the characteristics of the dough. Besides reacting with baking soda to produce the gas carbon dioxide, these acids form ionic bonds with the starches and proteins in the dough.

SAPP dissolves readily to form the anion pyrophosphate which interacts with the proteins in a baked good system to provide a moist texture. Also, it provides a buffer system for the dough in the pH range 7.3-7.5, which influences the color of the baked product.4


21 grams of sodium and 28 grams of phosphorus are present in 100 grams of SAPP.1

Commercial Production

SAPP is manufactured by partially neutralizing food grade phosphoric acid with sodium hydroxide or sodium carbonate to form monosodium phosphate. Dehydration of monosodium phosphate at 250°C will form SAPP.1

Currently, there is no known natural method for the production of SAPP.1


Because SAPP is slow acting and does not react quickly with baking soda, it is the most commonly used leavening acid for self rising flour for the home baker. Per 21 C.F.R. § 137.180(a) 2018, self rising flour must contain enough leavening acid to neutralize the baking soda, but the combination of both can not exceed 4.5 parts per 100 parts flour.

The quantity of leavening acid needed hinges on its neutralizing value (NV) which is defined as the quantity of baking soda needed to neutralize 100 parts of leavening acid. For SAPP, NV is 70.

Because SAPP can have a slight bitter taste, it’s important  to use sufficient baking soda in applications as well as use this leavening acid in combination with sugary goods such as doughnuts and cakes. Cake doughnuts are an important application for SAPP, where initial gas production is necessary for buoyancy in a fryer system. Also, SAPP is useful for cakes, where initial gas production is necessary for consistency of pan fill.

Other non-bakery food applications of SAPP include use as a chelating agent for processed potatoes, an emulsifying agent in cheeses and a curing accelerator in processed meats.1

FDA Regulations

In the United States, SAPP is affirmed as a multipurpose Generally Recognized as Safe (GRAS) food substance when used in accordance with Good Manufacturing Practices . (21 C.F.R. § 182.1087 2018).

Although, USDA allows the use of the synthetic ingredient SAPP in certified organic products (7 C.F.R. § 205.605 (b)), FDA considers a food product misbranded if a food has the label claim “All Natural”, but contains SAPP. In 2014, they issued a warning to a bakery using SAPP in a product labeled “ALL NATURAL.”4


  1. USDA National Organic Program. Sodium Acid Pyrophosphate, Technical Evaluation Report. 2010. Accessed 19 Feb 2019.
  2. Lampila, L. E. “Applications and functions of food‐grade phosphates”, Ann. N.Y. Acad. Sci. 2003. 1301: 37-44. doi:10.1111/nyas.12230
  3. Panko, B. “The Great Uprising: How a Powder Revolutionized Baking”, Smithsonian. June 20, 2017.
  4. Vetter, JL. “Leavening Agents”, Encyclopedia of Food Sciences and Nutrition (2nd Ed), Edited by Caballero, B. Elsevier Science. 2003. pp 3485-3490.
  5. FDA, CMS #433344, Warning Letter. Sept. 14, 2014. Accessed 18 Feb. 2019.


  1. David Rees June 12, 2017 at 11:41 am - Reply

    Is this the same as Tetrasodium Pyrophosphate

    • Ana Rinck
      Ana Rinck June 12, 2017 at 4:30 pm - Reply

      Tetrasodium Pyrophospahate (TSPP) has four sodium ions and Sodium Acid Pyrophosphate (SAPP) has two. They are related compounds, but not the same, as both share the Pyrophosphate base.

  2. Kenny October 10, 2018 at 9:09 pm - Reply

    Do SAPP react with Sodium Bicarb in powder form under some moisture about 10%?

    • Ana Rinck
      Ana Rinck October 11, 2018 at 11:45 am - Reply

      This is covered under the Application section.

  3. Neeraj Hasija February 20, 2019 at 6:14 am - Reply

    Hi.. Have a very specific question…We are using about 12g of Leavening agent in our Frankie wrap recipe… combination of 8g Sodium Bicarbonate and 4g SAPP..

    Unfortunately the pH of the dough is coming quite high about 6.8, due to which we are not getting good shelf life. Would you recommend changing it to 6g + 6g combination or 7g SAPP and 5g Sodium Bicarbonate. Would 7g + 5g combination help us in lowering the pH to about 6 which would help us enhance the shelf life.
    Look forward to your guidance. Regards

  4. Khalid April 28, 2019 at 5:17 am - Reply

    Do all the phosphates used in baking have similar properties?

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