Robinsons Old Tom clone

[Portreath]

I'm planning the brew Robinsons old tom from GWs BYOBRA. The recipe looks sound enough, although I'm guessing its based on a fairly good brew-house efficiency. as mine is only at about 58% at the mo I've worked into the recipe 700g DME to get me up to the 8.5%
Is this addition likely to make much difference to the finished brew?

 

[Horners]

Don't forget as well that BHE also suffers a bit with larger grain bills.

I did this recently and hit a starting gravity of 1.076 at 67% BHE. Had a bit of a shocker with the mash that day resulting in half of it being mashed at relatively low temperature meaning it over attenuated and got me back to target ABV.

Cant see the use of some DME will change it.

 

[Grealish]

I brew James Morton Paradigm Shift stout every Christmas, which comes in at about 14%. The grain bill is massive and inefficient so this year I decided to replace some of the base malt with DME I tried some a couple of weeks after bottling (it really needs a lot longer to condition fully) and it tastes great, but this is a very dark and complex beer that maybe masks the DME. One of my first brews was a partial mash (i.e. DME plus speciality grains) Old Tom kit from Brew UK and it was very good to my then untutored palate, which may augur well.