Rather than this why not try adding the dark grains at the end of the mash and steeping them for 10-15 minutes, recirculating and then running off. The higher the roast the less likely there is any diastatic power left so mashing is unneccesssary applies to crystal as well of course). Think of it as the difference between a freshly brewed cup of coffee and one that has been sitting on a hot plate for up to 1.5 hours. Anyone who has experienced that knows that there is a a much greater chance of extracting harsh bitterness and acidity from the grains this way. The other options are cold steeps and adding to either the boil or even during fermentation. The latter option allows for blending to taste giving even more control of the eventual outcome. You might reduce the crystal element anyway but this option allows you to deal with the bitterness, if it is indeed coming from the grain rather than hops.Kev888 wrote:I (again) detect a slight bitterness to the after-tase that isn't quite fitting. So I think I'll try some lighter grains next time and perhaps move some of the hopping schedule to be mostly later hops.
Kev
One cautionary note however is if you are relying on the darker grains to reduce the mash pH you will of course have to ensure the mash liquor and sparge water has been treated in advance.
