I want to make a recipe (all grains) that is based on 70% efficiency. However, I'm usually around 75%. I'm wondering what is the conventional way of scaling the recipe for the new efficiency. Actually, I'm seeing three possibilities:
1- Do the recipe as per 70% and add some water before fermentation to dilute the mash to the coorect OG. Problem: I will have to adjust the hops amount to compensate the larger volume.
2- Adjust all the grains to get the correct OG after the boil. Problem: putting less crytal malts, which don't add much to the OG, will certainly affect the color and the taste.
3- Adjust only the base malts. Seems to be right way...
So, I think of going with option 3. Is there anything I missed here ? Is there a better or standard way to do this kind of conversion ?