Continuation of the fermentation story

I wrote a few weeks ago about Carl starting a fermentation project (https://journeyinamazinggrace.blogspot.com/2024/05/starting-fermentation-project.html). He started the sauerkraut on May 9. 

He had also started some onions (a mixture of red/purple onions and vidalia (sweet) onions) on May 26, but that was only to need a week or so of fermentation. The onions were *very* smelly -- we had the odor of onions in the rig for most of the week. I thought at first it was just from cutting up the onions and the waste in the trash can -- but we had emptied the trash and onion smell doesn't usually stay around *that* long. The tops are not placed firmly on the jars during their fermentation stage (on the counter) because of the pressure they build up -- the fermentation process releases carbon dioxide. We found that some of the liquid would bubble out of the jar with the onions and the paper towels we had placed under the jars would get the onion smell. Carl would check the paper towels each day and they had to be replaced a few times.

Last week, on June 3, he decided that it was time to check his projects. He had ordered a pH tester, and we had gotten distilled water to rinse the testing device and keep it moist during the testing.

The scientist in his laboratory -- with the opened jars of sauerkraut...

... testing the pH.

Testing another jar's pH. The pH told him that it was safely fermented and had become acidic.

When the vegetables start the fermentation process, the brine is at about a level 5, slightly acidic, an unsafe zone where bacteria could grow. During fermentation, the brine becomes more acidic, creating an environment where bacteria will not grow (it needs to drop to an acidity of 4.5 or lower).

Applying the smell test.

He found that the sauerkraut and the onions were ready -- after fermenting 3.5 weeks for the cabbage, and 8 days for the onions. One jar of cabbage produced a less tart sauerkraut -- Carl figures it may not have gotten as warm as the other jars (we don't have a very controlled environment on the counter in the motorhome) so it experienced less fermentation than the other jars. He says that the onions are more mild tasting than they would have been raw, but he isn't as impressed with those as he is with his sauerkraut.