Anhydrous Monocalcium Phosphate | American Society of Baking
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Anhydrous Monocalcium Phosphate

Also known as coated phosphoric acid calcium salt

What is anhydrous monocalcium phosphate (AMCP)?

Anhydrous monocalcium phosphate CaH4(PO4)2 is an acidulant and slow-acting leavening acid. Its main uses include:

  • Household baking powders
  • Leavening agents for pre-leavened products

AMCP is essentially a monocalcium phosphate (MCP) which has been coated with a slowly dissolving phosphate material. This delays its reaction with baking soda.

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Monocalcium phosphate (MCP) was first introduced in the 1850s to replace alum as a baking acid. The first pure, free-flowing MCP became available in 1937. Then, the anhydrous/coated form (AMCP) was developed in 1939 as a slow-acting leavening acid.1


MCP can react rapidly in double-acting baking powder. However, due to its coating and reduced solubility, AMCP is better protected against ambient moisture. This prevents its rapid dissolution in water during mixing.2,3

The following table compares characteristics of MCP and AMCP, including neutralization value, amount of acid needed for neutralization and final pH of baked goods:

Leavener Neutralization value (NV)* Amount of acid needed to neutralize 100 g sodium bicarbonate (g) Final pH (baked goods)
Monocalcium phosphate monohydrate (MCP) 80 125 7.1 – 7.3
Anhydrous monocalcium phosphate (AMCP) 83 120 7.3 – 7.5

* NV is the parts by weight of baking soda from which all available carbon dioxide is released by 100 parts of the leavening acid (NV = g NaHCO3 neutralized by 100g acid)


A wide range of baked goods benefit from leavening with AMCP. A few including self-rising flour, phosphated flour, self-rising cornmeal, consumer prepared mixes, and household baking powder. It is always used in conjunction with baking soda.

The release of carbon dioxide from AMCP during mixing is much lower than that from MCP. The gas release increases during bench time but increases significantly when heated. These differences are mainly due to the reduced solubility of MCP via coating with condensed phosphates.

Leavener % CO22 min after mixing % CO210-15 min bench % CO2During baking
Monocalcium phosphate monohydrate (MCP) 60 0 40
Anhydrous monocalcium phosphate (AMCP) 15 35 50

Traditionally, mixes of AMCP and SALP are used in self-rising flours and the production of biscuit mixes as well as in frozen and refrigerated pancake batters. Benefits of AMCP in baking applications include:

  • Helping with the development of tender baked goods mainly biscuits and pancakes prepared from self-rising flour
  • Enhancing the resilience of doughs or batters
  • Providing for sustained baked goods oven spring

FDA regulation

Anhydrous Monocalcium Phosphate (AMCP) is considered ‘GRAS’ by the FDA. Further regulations are listed under 21 CFR182.1217.4


  1. Knox, W.H. and Schlaeger, J.R. US Patent 2,160,232 (1939) for the Stauffer Chemical Company.s  produced by coating MCP with potassium and aluminum phosphates.
  2. Vetter, J. L. LEAVENING AGENTS. In: Encyclopedia of Food Sciences and Nutrition. Edited by Caballero, B. Elsevier. 2003. Pp: 3485–3490.
  3. Baking update.
  4. CFR – Code of Federal Regulations CFR182.1217. Accessdata. Fda. gov. April 01. 2019. Accessed by Dec 19. 2019. Accessed by Dec 18. 2019.