section_path: Leavening/Aeration
section_name: Aeration
paragraph_text: Aeration
  
  Aerated bread is leavened by carbon dioxide being forced into dough under pressure. From the mid-19th to mid-20th centuries, bread made this way was somewhat popular in the United Kingdom, made by the Aerated Bread Company and sold in its high-street tearooms. The company was founded in 1862, and ceased independent operations in 1955.
  
  The Pressure-Vacuum mixer was later developed by the Flour Milling and Baking Research Association for the Chorleywood bread process. It manipulates the gas bubble size and optionally the composition of gases in the dough via the gas applied to the headspace.