That’s what I was thinking, just calculate it for yourself. Numbers vary too much from system to system. I’ve seen people claim 90+% (and done it myself with too fine a grind and multi-time-stuck-sparge), all the way down to 65% for folks trying to avoid husk flavors or just accepting whatever grind the grain vendor provides. That’s potentially a very big swing.
Even in Ron Pattinson’s books on traditional recipes in very big commercial breweries, there might be 15% difference in efficiency depending on what they were aiming for. Where every % point means money, that’s a lot of variation.
I enter a recipe as written into my software of choice. Then, using my system profile(s), adjust the OG to the recipe spec. That gives the ballpark grain bill based on original percentages that I further adjust to make sense to me (i.e. 7.6 oz —> 8 oz). I do the same thing with hops: enter hops based on original recipe then adjust IBU to original spec. That gives me the SG:BU ratio very near the original recipe.
We don’t get to choose if we live or die. Death is certain. We only get to choose how we live before we die.
What disapointed me was the inconsistent water profiles. Some looked complete. Some just said soft water and the do x, but soft water can be alkaline. One profile looked to be nonachievable. Several recipes had no water information.
In Brewer’s Friend, I plug in the recipe then adjust the efficiency until it hits the target OG. From there I can scale the recipe to my system and batch size.
If efficiency isn’t listed for a recipe, I assume it’s 72% because that seems to be the default broadly used in homebrewing literature and software. You can add the recipe to your brewing software and play around with the grain bill to hit the printed OG. That will give you the recipe efficiency. If you have beersmith 3 it’s even easier. You can add the recipe as written and adjust the BH efficiency to match the OG.
Sure, I can fool around, tweak, waste time, etc. However, I’d rather know the recipe efficiency. Knowing the recipe efficiency gives me an advantage when converting the recipe to my “brew house”.