At first the offer from the new IT service provider sounded very good, but when we looked a the nitty-gritty (die wesentlichen Details) of the contract, it became clear that there were a lot of hidden extra costs involved.
One origin theory for this idiomatic expression is that „nitty-gritty“ refers to the debris left in the bottom of a slave ships at the end of a voyage, sometimes including the slaves themselves. This racist background means some people consider the expression highly controversial and it has been banned from use for the police in the UK.
But in fact, the evidence suggests that the expression has no connection to the slave trade whatsoever. The expression can only be found in print once in 1937, and then more commonly from the mid 50s – long after the slave trade in the US and UK had ended. The exact origins of the phrase are unknown.