Can you scale hop quantities down linearly when planning for a smaller batch? As an example, if a 14 gallon recipe calls for 28 grams of hop XYZ, can I assume a 2 gram per gallon addition and add 11 grams for a 5.5 gallon recipe?
It’s a pretty good starting point. I usually scale linearly on the first batch, take good notes, and then make fine adjustments on the next try.
I’m with John and scale straight down on the first go. You’ll probably find that you will want to modify it a little after the first batch, but you need that first batch to set the baseline.
As long as your equipment and process is similar, yes, at that level you can just do a linear scale up/down. Scaling up or down for commercial equipment is where there are usually changes for hops due to various process differences (e.g. the amount of contact time at temperature).
Linear scaling will work just fine at the homebrew level. Remember that unless your getting your beer tested empirically in reference to IBU, you never really have an exact value and are just using equations as a reference point for flavor.
It can be scaled linearly providing that the AA% is the same as in the original recipe. Otherwise you will need to use brewing software to help calculate potential IBU’s in your finished product.