I've made a 5 gallon stout using 3.5kg Maris Otter, 1kg porridge oats, 0.5kg chocolate malt, 40g crystal hops. Used a beoir celtic ale yeast. After a few weeks in secondary, I opened a bottle this evening and a very interesting flavour. A nice roasty malty start taste but a very bitter finish / aftertaste. I want a little less bitterness next time so maybe a little less chocolate malt next time? Any suggestions on a perfect recipe and thoughts on using porridge oats instead of roasted barley?