- Hop heavily with amarillo - I have got a good orange note from it before but I'm not sure it would stand out enough in a stout?
- Add curacao orange peel (or ordinary orange peel) - not really sure about quantities as again it needs to stand up against the roast grain. I want a bigger orange hit than you'd get in witbiers I've tried with curacau OP.
- Orange essence/flavouring - probably the easiest, but I'm not sure about using it in a beer.
I'm most keen on using amarillo - It stands up to my self imposed reinheitsgebot

Any thoughts?
Cheers