Welcome to our fourth edition of Science Facts Sundays.

This is Part 4 in a series of notes I took about sauerkraut fermentation from Fermented Fruits and Vegetables. A Global Perspective. (Chapter 5, Part 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 sauerkraut 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):

Lactic acid bacteria (LABs) require very little oxygen.

Acetic acid bacteria require oxygen and oxidize alcohol to acetic acid (vinegar). [This is why you can achieve a vinegary "tang" even when you ferment aerobically. The oxygen causes the ferment to become vinegar instead.

LABs prefer a room temp of 62 - 72 degrees for the first stage and 72 degrees and above for second and third stages. [Please don't refrigerate!]

Salting your cabbage before packing your jar causes the juice from the cabbage to create its own brine. LABs can tolerate high salt concentrations, but prefer the 2-3% range. [I use 15 grams salt (weighed) per 2 pounds cabbage].

Water activity is another important factor. Water activity (wa) refers to the water “level” and needs to be high. A low water level invites yeast, fungi, and mold. [The exception to this, in my most recent experience, is that in a Fido jar you can have cabbage sticking right out of the brine and it will remain spoilage-free. This is due to the CO2 requiring a higher degree of pressure before releasing through the vulcanized rubber gasket on the jar. Additional airlock systems on the top of the jar, such as the three-piece airlock you add water to, allows CO2 to be released much easier, removing that nice blanket of CO2 over your ferment, and inviting spoilage. Try it! You'll see. I will be publishing those results soon.]

Stage 1 bacteria, leuconostoc mesenteroides, produce acid and gas. They appear as coccus and produce .25 - 3% of the LABs.

Stage 2 bacteria, lactobacillus plantarum, are bacilli (rod-shaped) that produce acid and a small amount of gas. They produce a LAB content of 1.5 - 2%.

Stage 3 bacteria, lactobacillus brevis, are also rod-shaped and produce acid and gas. Their job is to produce as much as 2.5% lactic acid bacteria.

The end product of sauerkraut will include mostly lactic acid, as well as a small amount of acetic acid (vinegar), propionic acids, CO2, and a small amount of alcohol and aromatic esters.

The acidity (referring to lactic “acid” bacteria population, not pH) controls spoilage organisms. For a longer shelf life, allow your ferment to go through all three stages of bacteria.

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 Sauerkraut Fermentation, Part 1
• Notes on Sauerkraut Fermentation, Part 2
• Notes on Sauerkraut Fermentation, Part 3
• Notes on Sauerkraut Fermentation, Part 4
• Notes on Sauerkraut Fermentation, Part 5

Similar Posts:

Science Facts Sundays: Notes on Sauerkraut Fermentation, Part 3
Science Facts Sundays: Notes on Sauerkraut Fermentation, Part 2
Science Facts Sundays: Notes on Sauerkraut Fermentation, Part 1

Want to learn more about herbs? proud contributor