Editing Leavening agent (section)

===History===
Chemical leavening using [[pearl ash]] as a leavening agent was mentioned by [[Amelia Simmons (author)|Amelia Simmons]] in her ''[[American Cookery]]'',<ref>{{cite book|last=Simmons|first=Amelia|author2=Mary Tolford Wilson|title=The First American Cookbook|edition=1984 reprint|orig-year=1958|year=1984|publisher=Dover|location=Mineola, NY|isbn=0-486-24710-4|url-access=registration|url=https://archive.org/details/firstamericancoo00simm}}</ref> published in 1796.<ref>{{Cite book |last=Smith |first=Andrew F. |url=https://books.google.com/books?id=GZVweuXhZlkC&dq=amelia+simmons+american+cookery+1796+albany+new+york&pg=PT565 |title=The Oxford Companion to American Food and Drink |date=2007-05-01 |publisher=Oxford University Press |isbn=978-0-19-988576-3 |language=en}}</ref>

Since chemical expertise is required to create a functional chemical leaven without producing off-flavors from the chemical precursors involved, such substances are often mixed into premeasured combinations for maximum results. These are generally referred to as [[baking powder]]s.  Sour milk and carbonates were used in the 1800s.  The breakthrough in chemical leavening agents occurred in the 1930s with the introduction of [[monocalcium phosphate]]s {{chem|(Ca(H<sub>2</sub>PO<sub>4</sub>)<sub>2</sub>)}}. Other leavening agents developed include [[sodium aluminium sulfate]] {{chem|(NaAl(SO<sub>4</sub>)<sub>2</sub>·12H<sub>2</sub>O)}}, [[disodium pyrophosphate]] {{chem|(Na<sub>2</sub>H<sub>2</sub>P<sub>2</sub>O<sub>7</sub>)}}, and [[sodium aluminium phosphate]]s {{chem|(NaH<sub>14</sub>Al<sub>3</sub>(PO<sub>4</sub>)<sub>8</sub>·4H<sub>2</sub>O and Na<sub>3</sub>H<sub>15</sub>Al<sub>2</sub>(PO<sub>4</sub>)<sub>8</sub>)}}.  These compounds combine with sodium bicarbonate to give [[carbon dioxide]] in a predictable manner.<ref>John Brodie, John Godber  "Bakery Processes, Chemical Leavening Agents" in Kirk-Othmer Encyclopedia of Chemical Technology 2001, John Wiley & Sons. {{doi|10.1002/0471238961.0308051303082114.a01.pub2}}</ref>