- "conviction" could replaced with "belief" here.
- "accounted for" could be replaced "considered" or perhaps "researched" . (anotherAnother similar phrase is "take stock of").)
- "for all my [...]" could be replaced with "as a result of my [...]" here . (in otherThe result is contrary to what was expected, so in some contexts it may meancould be replaced by "despite my [...]").
The author is saying that his belief that fermenting vegetables (using the way that he is familiar with) is very easy caused him to not consider that other cultures would have different ways of fermenting vegetables.