23 August 2007

Baking Theory Notes: Fermentation Chemistry


Remember: Fermentation starts when the mixer stops!

Control Fermentation through:

  1. Temperature
  2. Time
What happens during the fermentation process?
  • Gas is produced --> Carbon Dioxide {When Dough is mixed gas is caught by the gluten and the gas rises}
  • (water & flour cause enzyme activation)
  • Gluten is modified --> Dough becomes balanced so dough is workable : Elasticity --> Extendability
  • Flavor is developed (Acidity)
  • Alcohol is developed ("Alcoholic fermentation")
*To test the "alcoholic fermentation" theory ---> when you are ready to mix your formula, open a starter, either one retarded or left on the bench (Ciabatta or Croissant are especially potent!), lean in --- (as a former instructor would explain: "you rip back- because alcohol has hit your brain", he had such a big grin when he said this ) I am telling you --- it'll knock your socks off. The more "bake-tarded" (my own baker slang) you become, the more you anticipate smelling those starters! Ha HA!


fermentation chemistry simplified
click here to see a bigger sized diagram of the chemical changes of fermentation.

Biochemical Catylist: an organic substance formed by living cells (yeast), is able to cause changes in other substances {i.e bacteria, fungus or both } without changing it's self .

yeast cell budding

Diastatic = has enzymes
Non-diastatic = enzymes have been killed

Diastic Enzymes:

---> Supplied by flour / or Malt (sugar)
  1. Alpha-Amalase works on Amylose ---> Converted to Dextrin (sugar)
  2. Beta-Amalase works on Amylopectin ---> Converted to Maltose (sugar)
*These diastic enzymes are important because they work on STARCH.
---> Wheat is 70% starch (bran is protein)


--->Amylose --->

Diastatic Enzymes from flour (from milling) work on the damaged starch (i.e gelatinized (from heat / baking) and convert it to sugar (2% of starches) .

End result is mostly Maltose. Yeast cannot metabolize maltose.

  1. Maltase (enzyme) ---> converts to Fructose, Dextrose / Glucose)
  2. Sucrose [beet or cane] (granulated sugar) ---> Converts into Glucose
  3. Invertase (enzyme from yeast) ---> converts Glucose into Sucrose

Yeast takes maltose (enzyme) and converts it into Fructose, Dextrose / Glucose {allows yeast to eat it).

These processes take place if:
  1. Optimal Temperature
  2. Right moisture Content
  3. Allowed Optimal time
Zymase (yeast) ---> Reacts with simple sugars and injects CO2 into the dough causing it to rise. Produces alcohol.

Simple Sugars:
  1. Fructose = CO2
  2. Glucose = CO2
  3. Dextrose = CO2
Proteolytic Enzymes
  1. All from flour
  2. Can be found with Diastatic Enzymes
---> Protease ---> Converts protein ---> Modifies the gluten so dough is workable (softens and makes extendable)

*Over mixing dough will break dough down into "slime". I've seen this happen, it ain't pretty. Kinda resembles the stay puff marshmallow man (as the ghostbusters cross streams)
when he is obliterated --- a bumpy, jiggly white mass. yuck.



5:22 AM, September 07, 2007 Reply  

very intresting

6:39 PM, September 11, 2007 Reply  

Thanks for your comment Derek ---

For most,
The chemistry behind baking is weird and mysterious, until you study it a little ;)

As a baker you probably appreciate these little oddities behind the art, yes?

11:04 AM, November 08, 2010 Reply  

Alcohol is always developed during fermentation ? by the way this is one great article ;)

7:13 AM, May 14, 2012 Reply  

We sometimes need to be caution when we use fermentation. It's just a step between success and failure. Thanks for explaining to us this process.

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