Originally Posted by bionara
Excellent, thank you Brewsit. Should I still add the 5g hops as stated in the last 10 mins of boil (which is about 40 mins away according to my timer!).
Yes and if you can recovery the hops from the mash grist. If they are pellets (which would mean you can't) then I would be tempted to add another measure of the same bittering hops again as the recipe calls for at the start of the boil.
As already said, additions at low temps like 65-70C won't increase bitterness much but instead add a smooth aroma/flavour. If you don't have the bittering hops at the start of the boil the beer will end up too sweat.
If the extra aroma/flavour turns out to be to your dislike apon drinking you can age the beer and it will reduce with time, which given its old perculiar won't be a problem as it will improve with age being both high ABV and dark. Old P is also quite a sticky and sweet beer that imo could benifit from extra hopping.