Originally Posted by Ben_Persitz
Is it that when you talk about efficiency, you're really meaning how much sugar you extract? So that's the 80%? And then total efficiency (which people dont often talk about?) is what you actually get into the brew pot (The 70%)?
Can someone explain?
I think what is throwing you off is that final volume of 5.5 gallons. If you were planning on a 5 gallon batch and using 5 gal to find your target gravity, your OG is going to come in low at 5.5 gallons.
Here is how I look at it to help myself be consistent. I always take the OG and volume from the kettle. So if my target OG is 1.052 at 5 gallons, that is what want post-boil.
Now my "Mash" efficiency is typically 75% (or more accurately Mash + Lauter/Sparge Efficiency) so I know I need about 6.25 gallons of pre-boil gravity 1.042. Pre-boil gravity and volume for me, are the most important number regarding efficiency. Knowing that for given amount of grain I will extract 75% of the potential gravity into the kettle helps me determine how grain I will need for a given recipe.
On brewhouse efficiency, I am not as consistent. I always lose between a quart and 3/4 of a gallon going to the fermenter due to the amount of hops / break material I leave in the kettle.
I have found this to be really helpful:http://braukaiser.com/wiki/index.php...ing_Efficiency