Thursday, March 21, 2013

Fermentation Basics: A Tale of Two Fermentations (Part 2)





Fermenting Feed Series - Part 2 of 3

FERMENTATION BASICS:  A TALE OF TWO FERMENTATIONS

By Sue -

There are several different types of fermentation that are used for different results depending on the item that you are fermenting and the results desired. 

In this article I'll attempt to provide a very basic overview of Alcohol Fermentation and Lacto-Fermentation processes.  Hopefully this short overview will encourage you to research and learn more on your own!

When fermenting feed for my chickens, I use lacto-fermentation.


Chicken feed fermenting in glass container.


FERMENTATION - WHAT'S GOING ON IN THAT BUCKET ANYWAY?

In very general terms:

Yeasts consume sugars (carbohydrates) and produce alcohol.

Bacteria consume sugars (carbohydrates), starches or alcohol and produce acids

  
FERMENTATION FOR ALCOHOL 

-When fermenting to produce alcohol, various yeasts are used.  These yeasts digest the carbohydrates (sugars) and produce alcohol.   
-In high concentrations, alcohol is toxic even to alcohol-producing yeasts which will eventually die off when the concentration of alcohol becomes high enough in the fermenting mixture.
Example:  Almost everyone has had a gallon of apple cider go "hard" over time as the various yeasts that are present in the environment do their work and begin producing alcohol while they're enjoying consuming the carbohydrates in the cider.  Now If you keep that hard cider long enough, it will eventually turn to vinegar...so what happened?

- Acetobacter bacteria convert alcohol to acetic acid which is the main ingredient in vinegar; this process is aerobic (open to the air).  The "mother" in an unpasteurized vinegar contains these bacteria and other health-producing ingredients.

According to Bragg.com their raw apple cider vinegar (ACV) Contains:  "enzymes and important minerals, such as potassium, calcium, magnesium, sulfur, chlorine, phosphorus, iron, silicon and other trace minerals. The vitamins contained in ACV are bioflavonoids (vitamin P), beta-carotene (precursor to vitamin A), vitamin C, E, B1, B2, and B6."

-Acetic acid preserves food by lowering pH (raising acid level) and making an environment that is unfriendly to harmful bacteria.

Notes: 
-Alcohol is processed by the liver rather than through the digestive system.  Liver damage can occur with excessive consumption over a long-term basis.


LACTO-FERMENTATION
-During lacto-fermentation, various Lactic Acid Bacteria (LAB) are used to digest the carbohydrates (sugars) and produce lactic acid.  This lactic acid is what produces the "tangy" or "sour" flavor that is found in items such as yogurt, raw lacto-fermented pickles, raw lacto-fermented sauerkraut, etc.
-High concentrations of LABs are beneficial to the digestive tract and immune system and even produce additional nutritive value in the form of B Vitamins, Vitamin K2 and Enzymes.  (See Part 1 BENEFITS OF LACTO-FERMENTING FEED FOR CHICKENS for more information.)

"The proliferation of lactobacilli in fermented vegetables enhances their digestibility and increases vitamin levels. These beneficial organisms produce numerous helpful enzymes as well as antibiotic and anti-carcinogenic substances. Their main by-product, lactic acid, not only keeps vegetables and fruits in a state of perfect preservation but also promotes the growth of healthy flora throughout the intestine."  (From Weston A Price Foundation Website Article:  Lacto-Fermentation)

 -Lactic acid preserves food and produces an environment that is unfriendly to harmful bacteria.   This type of food preservation has been used for centuries.  As the acid level raises in the food (pH lowers) it prevents "deadly" bacteria from being able to grow in the food

Lactic Acid Bacteria...."does inhibit most Gram-positive organisms including spore-formers such as Clostridia Botulinum and heat-resistant spoilage organisms."  (Quote from:  http://silvalab.fsnhp.msstate.edu//vinegar_lactic.pdf)

IMPORTANT NOTE:  This is one of the reasons that preserving lower acid foods via lacto-fermentation is safer than heat canning as deadly bacteria such as botulism can grow in low acid, heat-canned products due to their ability to proliferate anaerobically.  (See Part1 BENEFITS OF LACTO-FERMENTING FEED FORCHICKENS for more information.)




-As the lactic acid increases, molds/yeasts/fungi are also kept in check, allowing the beneficial "probiotics" to flourish in greater quantities while discouraging overgrowth of alcohol-producing yeasts.

Lacto-fermentation is generally anaerobic (not open to the air).

-Common food items that use this process are fermented milks (yogurt, cheese, kefir, buttermilk, etc.), fermented vegetables (sauerkraut, pickles, kimchi. etc.) and fermented meats (corned beef, sausages and fish).


And....Chicken Feed!

Healthy chicks enjoying fermented feed.  Photo by Vicki Servi


For more information on fermentation see:

Real Food Fermentation by Alex Lewin
This book has great photos and a good basic overview of fermentation of many types of food items for people!

Lots of great information on healthy preparation of foods including lacto-fermentation and sprouting.
 
This site has many articles and videos showing a variety of fermenting processes. 
Also sells various LAB starter cultures suitable for various types of fermentation.

Very interesting book worth reading for a broad spectrum of nutrition topics including fermentation and sprouting.



 - Sue

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