What was noah's sin?

Answer 1

Noah was believed to have helped preserve the animal life of the Earth. God informed Noah that he was going to flood the Earth and asked Noah to help save the species of animals by gather 2 of every "unclean" animals and 7 of every "clean" animals. So Noah did and while doing so he built the Ark; a giant wooden boat capable of carrying tons and tons of weight. Later on, he and his family had waited in the Ark when the flood happened with the animals. Either during the flood or after the flood, Noah had sacrificed some of the animals. In the book "What The Bible didn't say" it states that it is most likely that Noah brought 7 pairs of clean animals instead of 7. But MY (Akkere's) hypothesis is that he sacrificed the seventh animal (which is why there was uneven) on the altar. So basically when the great flood had happened, Noah saved animal life.

Answer 2

He got drunk and found himself in an undignified state. (Genesis ch.9).