Correcting high pre-boil OG (underestimated effeciency)?

[dotsoncs]

I took my second shot at AG over the weekend, trying to brew an American Pale Ale. I barely hit the 70% efficiency on my initial AG batch so I put some time into to improving my process; working my water chemistry, having a friend crush my grain, etc.

All of the work seems to have paid off, almost too well. The recipe - calculated at 72% efficiency - was supposed to hit a pre-boil SG of 1.045. I rang in around 1.056. This meant a final post-boil OG of 1.068 which was well above the 1.055 that I was shooting for and coming in around 85% efficiency.

I decided to let it ride and just deal with a higher ABV but I wanted to know if there was anything that I could've done to drop the gravity pre or post boil. My first instinct would be to add some RO water but wasn't sure if there would be any repercussions to doing so.

Any tips on how to handle this in future brew sessions?

 

[forstmeister]

Simply reduce your grain bill and save money on each brew if you can replicate the results.

 

[TyTanium]

Any tips on how to handle this in future brew sessions?

A good problem to have. If I'm high on pre-boil gravity I usually just add more water to hit my numbers. But you could also reduce your boiloff rate by turning down your burners to a less-vigorous boil. Or you could reduce boil time if that's an option for your style.

I usually just go with option 1, or leave it with the higher gravity and adjust the hops accordingly.

 

[MrSpiffy]

Either that, or I'd imagine you could just top off to the OG you're looking for and have more beer.

Edit: TyTanium beat me to it!

 

[dotsoncs]

A good problem to have. If I'm high on pre-boil gravity I usually just add more water to hit my numbers. But you could also reduce your boiloff rate by turning down your burners to a less-vigorous boil. Or you could reduce boil time if that's an option for your style.

I usually just go with option 1, or leave it with the higher gravity and adjust the hops accordingly.

Figured I could've done that, just wasn't sure. How would I need to adjust the hops?

 

[dbreienrk1]

Figured I could've done that, just wasn't sure. How would I need to adjust the hops?

You wouldn't...

 

[TyTanium]

You wouldn't...

But wouldn't your gravity be lower or your volume be higher?...so technically you would, but I guess unless you're way off the amount is trivial.

 

[TheChemist]

It's already been said, you can just add more H20 - save yourself some time, and add boiling water to the wort to help bring it up to boil. If you're wanting to hit your target OG exactly, easiest thing to do it calculate how much water to add.

specific gravity x volume (L) = total sugar in solution
sugar total / target OG = target volume (L)
target volume - original volume = how much to add.

If you're really bothered about your hops, dotsoncs, you can just recalculate; unless you're making a crazy heavy beer, the gravity won't affect hop utilization too much.

volume x target IBU x 10 / alpha acid % x 25

'Hope this helps!

 

[dotsoncs]

TheChemist - That's exactly what I was looking for and what I expected.

Appreciate all of the responses. Happy brewing!

 

[DSmith]

I plan for 70% efficiency and replace some of the wort with brewing water to meet the recipe, or not if it's only a few gravity points.

Equations for Efficiency Too High

(PBV) Pre-Boil Volume [Gallons]
(PBG) Recipe or Brewing Program Pre-Boil Gravity
(AG) Actual Mash Gravity
(RV) Removed Volume to be Replace with Brewing Water [Gallons]

RV = PBV – PBV*PBG/AG

Example

PBV = 4.125
PBG = 48
AG = 54
RV = 4.125-4.125*48/54 = 0.46 gallons (Remove this volume of wort and replace with this volume of brewing water)