Herms great Mash Eff but low Brewhouse Eff....

[newtonfb]

Ok so im confused. Finally got my Herms setup and done a couple brews with it. Im gettting over 90% eff in my mash eff but when it comes to Brewhouse im getting 70, give or take a few. I dont know if im calculating it right or not. I left my setup at 72% (beersmith default) and it seems like i keep hitting those numbers right on. The only thing that I know that is off right now in my system is my boil off rate becuase im still adjusting that.
Is it normal to have a high mash eff but low brewhouse? Whats a good brewhouse eff%? From what I have searched it seems like 85% is what i should be shooting for?

 

[McKnuckle]

Conversion efficiency is how much sugar you extracted from the grain into your full volume of water, based on the grain's potential. This is usually between 80-90%, could be a tiny bit higher.

Lauter efficiency addresses the amount of wort you collected vs. how much water you used. Grain absorption and mash tun losses are accounted for here. You will always lose a couple more points, because you can't avoid grain absorption.

Mash efficiency is the product of these two percentages.

Brewhouse efficiency is the total amount of wort that hits your fermenter - with the evaporation volume added back - divided by the total amount of water you started with, multiplied by the conversion efficiency. In other words, it factors all volume losses except for evaporation (which is not counted), along with sugar extraction.

So even with 100% conversion efficiency, you would still have a brewhouse value of around 85-90% as a theoretical maximum, just due to grain absorption. You'd have to dump all hop and break trub into the fermenter, and have no other losses, to achieve that. Maximum brewhouse efficiency of around 80% is more feasible.

In fact, one way to look at it is that your brewhouse efficiency will equal your mash efficiency if there are no additional post-mash losses.

 

[jmark]

As long as your mash efficiency is pretty good and, more importantly, consistent, then I wouldn't worry so much about the brew house efficiency (although I certainly would try and dial-in your system numbers so you know what effects evaporation, absorption etc have).

I actually factor in larger losses than needed going from BK to fermenter and from fermenter to keg so I can leave behind a consistent amount and not have to worry too much about whether a particular beer is going to end up with a lot of waste to hop debris etc. All I care about at the end of the day is my post boil gravity and having enough wort that eventually gives me, say, 5 gallons in the keg. If that's 6 gallons post boil and I leave .5 gallon in the BK, whether or not that .5 is thick with trub and hops doesn't matter.