ferment, foment

Ferment or ferment means to allow bacteria, yeast or mold to grow, as in the making of wine or beer,or bread, or sauerkraut, until sugar is converted to gas, acid, or alcohol--
It will take a couple of weeks for the sauerkraut to ferment.
You'll need to keep that at just the right temperature if you want it to ferment.

Ferment or ferment also means civil disturbance or turmoil--
The country has been in a state of religious ferment since the arrest of the popular preacher.
The ferment subsided after a few days.

Foment or foment means to incite or instigate--
The prosecutor claimed that he meant to foment revolution with his inflammatory speech.
He is charged with attempting to foment a riot.

Now that you know that, you can say--
"The separatist group meant to foment a riot that would become a nationwide political ferment."

Note--"foment", when used as a medical term, means to apply heat or a hot poultice to--
The doctor used a cloth soaked in hot vinegar to foment the affected area.