"establishing the buffer"

[Bolverk]

Howdy y'all,

I'm re-reading Arroyo's circular 106 on Rum manufacturing by Boston apothecary

For those that haven't read it...
https://www.bostonapothecary.com/circul ... royo-1938/

Specifically on the pretreatment of raw materials.
He recommends making a molasses and water slurry, then treating it with lime/acid to a starting pH of 5.8, then add lime to 7, then acid back down to 5.8.

He says this is "establishing the buffer" what do you suppose he means by that? Doesn't the acid cancel out the base? Wouldn't the use of something like oyster shell be more of a buffer than adding lime slurry then nullifying it?

Thanks
B