Welcome to Science Facts Sundays.
This is part of the notes I took about fermentation from Fermented Fruits and Vegetables. A Global Perspective. (Chapter 2). It was one of the sources I used when writing The Science Behind Sauerkraut Fermentation a couple of months ago (my ebook version is here).
You may find this geeky - so be forewarned! If fermentation doesn’t appeal to you, check back in a few weeks and I’ll have moved on to something else that you may be interested in.
Here are some morsels for you to chew on (written in my own words):
Aerobes grow in the presence of oxygen; anaerobes grow in the absence of oxygen.
Facultative anaerobes are in the middle- they can adapt to the prevailing conditions and can grow either in the presence or absence of atmospheric oxygen.
Microaerophilic organisms grow in the presence of reduced amounts of oxygen. [Lactic acid bacteria are microaerophilic.]
When you have an aerobic ferment, you are allow oxygen access to the food you are trying to ferment. Instead, you want an anaerobic environment that will keep the oxygen out. This will keep the spoilage organisms at bay. Mold needs oxygen to thrive - suffocate it!
There are three temperature categories bacteria fall under. Psychrophilic, mesophilic, and thermophilic. Lactic acid bacteria are mesophilic and prefer the following temperatures:
- Minimum temperature: 50-77° F
- Optimum temperature: 86-104° F
- Maximum temperature: 95-122° F
[Any lower than 50°F - such as you refrigerator temperature - can greatly decrease, or suspend, LAB activity. At temperatures higher than 122°F and LABs can be destroyed.]
The nutritional needs of lactic acid bacteria are simple: give them simple sugars or complex carbs and they are happy. They require lots of “food” since they have high energy.
pH i s a measurement of hydrogen ion concentration. A pH of 4.6 and lower is a high acid food which will not permit the growth of bacterial spores. [Your ferment is safe from "bad bacteria" at this point.] A pH of 4.6 and higher is a low acid food and can allow for growth of bacterial spores.
Through fermentation, and achieving a final pH of 3.5 or lower (preferably closer to 3.2), you have created a food that will not spoil.
Although many bacteria prefer a pH of 7.0, Lactobacillus and Streptococcus are acid-resistant. [This works out well, because these are the guys we want in our ferments!]
Unfortunately, most molds and yeast are also acid-tolerant. [What to do? Keep the oxygen out!]
That’s it for today! I hope you learned something. If you did, feel free to leave me a note in the comments If you didn’t, then you are definitely a geek! 
- Notes on Fermenting Pickles
- Stages of Fermentation, and Moisture
- Fermentation and Oxidation, Temperature, Nutritional Requirements, and pH
- More Notes on Fermenting Pickles
- And More Notes on Fermenting Pickles
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| Lea Harris founded Nourishing Treasures in 2006. A mom passionate about her family's health and well-being, Lea believes education is power. Encouraging others to take baby steps in the right direction of health for their families, Lea's goal is to raise awareness of what goes into our mouths and on our bodies, providing natural alternative information that promotes health and prevents disease by using traditional foods and nature's medicine.
Lea is a Certified Health Coach graduate from Beyond Organic University, and a Certified Aromatherapist graduate from Aromahead Institute. "Like" Nourishing Treasures on Facebook, join the Nourishing Treasures Group on Facebook, follow @NourishTreasure on Twitter, and subscribe to our newsletter. You can also find me on Learning About Essential Oils forum, and Fido Fermentation Facebook group. Disclaimer: I use affiliate links wherever possible. So if you click on a link, and make a purchase, I might make a small commission, but it doesn't cost you any more. |
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