The boss had to show me the procedure more than once. When the product loses its yellow color, run analysis on a jug of the uncolored product. If the density is low, the product was agitated too much (whipped). Determine how much salt and color is needed to “fix” the product still in the storage tank. Complete the production run.
This did not make any sense. If the product was agitated too much, what happened to the salt and color? It should be well mixed.
The next day, before filling jugs, I climbed the massive storage tank and looked inside. The product was separated. No color could be seen. Beach ball size globules floated in a colorless oil. It did not look appetizing. The heavy ingredients like salt and color must have settled to the bottom of the tank. Lighter ingredients floated to the top. A jug from the middle of the production run was less dense because the heavier ingredients were in the jugs from the beginning of the production run. The problem was not over agitation; it was under agitation.
The storage tank had an intermittent agitation setting that kept the product stable before packaging with minimum agitation. Whoever set up the machinery must have known the product would have a tendency to separate. That’s why the jug said, “Shake well before using.” Since bad batches were incorrectly diagnosed as too much agitation, it became taboo to use the agitator. Some batches sat a day without agitation before packaging.
Our shift started using the agitator and the bad product went away for one year. When first shift learned we were using the agitator, things went south. But that’s a story for a different day.
“What’s the opposite of the current process?” is a great question. It works more than you would expect.
How could we have caught this problem sooner?
Make it easier to look inside the finished product storage tanks. The top of these tanks were close to an overhead walkway. Strolling down a ramp is much easier than climbing an oily, two-story ladder wearing a safety harness.
When a batch changes during packaging, analyze samples throughout the production run. This would have identified the high salt content in the first jugs. No one ever questioned the quality of yellow product. A batch should be consistent throughout the production run.