I made a Hydromel (beer-strength mead) around 5% using champagne yeast. After fermentation I split it into a few small batches... some I added ginger, some I added orange zest, some remained un-modified.
After leaving for a while, I then primed it all and bottled. But for some reason while the un-modified version carbonated very nicely, the orange-zested one has remained totally flat. I don't know if the orange could be to blame, or if it's more likely the way I bottled it could have killed the yeast?
What are some common/likely reasons that bottle-carbonation wouldn't work, given that the sugar levels were the same?