This past week, as part of my Independence Days Challenge activities, I put together a sauerkraut ferment, which is lactofermentation of cabbage.

As it turns out, I’m not real great at calculating in my head. I know this, because:

  1. I used 1.5-tablespoons of salt for 1.5-pounds of cabbage;
  2. It is known that adding too much salt to a bacterial culture slows the bacterial growth rate; and
  3. My ferment hasn’t grown much since I put it together.

Which leads me to ask “How the Hell can someone who earned a Ph.D. in biochemistry be so crappy at math?”

Because I estimated in my head. I didn’t actually do my calculations on paper. That’s how.

Anyway, this is what the jars look like after 4-days of incubation. The cultures have been sitting on my kitchen counter, covered with paper sacks to keep light out. The fluid is pretty clear and there are only a few bubbles on top. Though you can’t see it in this shot, there are only a few bubbles in the air locks.


Here is a closer look.  As you can see, the fluid (purple bracket) on the top is very clear, not cloudy. However, there are a few bubbles formed in the cabbage (against the glass) and some at the fluid meniscus (purple arrows). The blue arrow points to the air above the fluid. The green arrows point to the crock rock that is holding the cabbage down.


Here is a closer look at the bubbles in the cabbage. See all of the little bubbles (purple arrows) among the shredded cabbage? The bubbles indicate that the fermentation is still progressing, though very slowly.


Why is my ferment growing so slowly? I simply added too much salt (1.5-tablespoons of salt for each 1.5-lbs of cabbage). If I had added even more salt, I could have stopped the bacterial growth all together.

What is the correct amount of salt to add to ferment cabbage into sauerkraut?

Here are the calculations (on paper).


So, I used a half-teaspoon too much salt.

I find it interesting that what seems like a small increase in salt (to me) is enough to slow the growth of the lactobacbacilli doing the fermenting.

But, if you think about it in terms of concentration, this really is a big increase in salt concentration.

Clearly, this is not optimal growth conditions.

What now?

  1. I’m going to let the fermentation finish. It will just take longer and the kraut will be too salty. But, we can always rinse some of the salt off before eating the kraut.
  2. I’m going to write down the correct amount of salt to use and stick it on the inside of my spice cabinet door. Then I can always double check the amount before I make more sauerkraut. “Measure twice and cut once,” and all that good stuff.
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