Originally published on NourishingTreasures.com in 2012. Photos referenced are not included.

Well it’s been two months since I posted Sauerkraut Survivor – Final Report. I told you I would let you know how the jars held up in refrigerator storage. This is that post.

I was actually really surprised that only one jar did not turn brown. I was even more surprised when I discovered which jar it was!

I guess it just goes to show that you never can know what to expect when you do experiments. That is why there are “hypotheses” – guesses – as to what you expect or assume will happen.

And then there is science.

Surprises of Sauerkraut Science

My first surprise was discovering that yes, oxygen exposure matters when it comes to ferments. So does mold, yeast, and temperature. I shared those findings in The Science Behind Sauerkraut Fermentation.

Then was the surprise that yes, a threaded seal can provide a good barrier against oxygen. I shared with you my Pressure and Vacuum Test Results.

Sauerkraut Survivor – Final Report showed that yes, you can save money by using economical jars for fermenting – and that there are many options.

Most recently I found that yes, you can ferment without submerging cabbage under the brine (no fussing with weights!), as long as you use a Fido. I shared that in my post can Fido jars defy science? Can they provide a fail-safe, spoilage-free ferment with no brine cover?. Edited to add: I was unable to experiment with other jars at the time, but now that I have published my fridge results I can now use those lids to see if there are other jars that do not need a weight in.

I also recently showed you that yes, Fido jars do off-gas (they do not explode) in my YouTube videos posted here: Do Fido jars explode? Do they off-gas? Let’s find out (video).

I also discovered (and have begun drafting a post on this) that yes, you can leave your ferment on your counter (you do not need to refrigerate) for a sweet/tangy/salty ferment that even your kids will devour. I will also share with you how after fermenting sauerkraut 4 weeks, I then opened it and began to eat out of it 1-3X per week for the next 4 weeks with no spoilage. I have just opened my 8 week counter jar and it looks great!

Stay tuned in 4 weeks when I compare my 12 week fully-fermented counter kraut to kraut that’s been in the fridge as long.

What do my eyes say?

These are the best-looking three jars out of the bunch. Jar #2 has no browning at all, followed by Jars #13 with the least browning and Jar#12 with slight browning.

Browning indicates some oxygen has gotten to the cabbage – and the Vitamin C content is low to nil where it is browned.

Take a look…(and click for larger photo).

Jars from left to right: Jar 2 (Olive Oil), Jar 13 (Pickle Pro), Jar 12 (Cooking God’s Way airlock system).

Below you can see all the jars together (click for larger photo):

Jars from left to right: Jar #2 (Olive Oil), Jar #7 (White lid with baggy), Jar #8 (White lid with airlock (in the fridge it was just white lid)), Jar #9 (Metal lid), Jar #10 (Metal lid with airlock (in the fridge it was the metal lid with holes plugged)), Jar #12 (Cooking God’s Way airlock system), Jar #13 (Pickle Pro), Jar #14 (Pickl-It – which was stored with a plug – photographed with the airlock).

What does the ‘scope say?

I took brine samples and used this AmScope microscope to check for spoilage. I captured the images with this AmScope camera attached to the ‘scope.

I did see the stray “slinky,” but did not detect any spoilage organisms (mold or yeast).

The LAB activity was more dense in Jars 2, 8, and 13, and more mature in Jars 2, 9, and 13. I am not sure what to make of that, if anything. I do know when the LABs have made as much lactic acid as possible, the ferment is over – their jobs are complete – and they die off. So I don’t want to read too much into LAB density or maturity at this point – but I’m sharing this with you as an FYI.

Here’s a peek at the brine – click for larger photo.

Jar 2
Jar 7
Jar 8
Jar 9
Jar 10
Jar 12
Jar 13
Jar 14

What does my nose say?

No, this part isn’t very scientific :) But here’s what my nose had to say about the jars…

Jar #2 – Very mildly like yummy fresh hard-boiled eggs. Probably sulfur?

Jar #7 - Awful! I jerked my head back so quick. Chemically? Perhaps from the baggy? Hard to say what. Just bad!

Jar #8 - Mildly unpleasant – chemicals?

Jars #9 and #10 - Horrible metallic/rubber smell. Eww! Take a look at the photo below – this is probably why…the tops of the ‘kraut had a little bit of rust flecks on them.

Jar #12 – It’s possible I might smell rubber, but I am not positive.

Jar #13 – Mild something. I almost want to say “smoky” – but that isn’t it. Not unpleasant, nothing distinct.

Jar #14 – Pleasant tang.

I definitely would not use metal lid and ring for long-term ‘fridge storage. They do make delicious kraut, though!

Final Words

Jars that work wonderful for creating sauerkraut, may not be the best for fridge storage. I would not use a metal lid and ring for long-term fridge storage – unless I needed added iron in my diet ;) And the baggy seemed to give off some funky smells, too.

My top 3 jars for fridge storage would be Jar 2 (Olive Oil), Jar 13 (Pickle Pro), and Jar 12 (Cooking God’s Way airlock system).

So there you have it!