Calculating Mash Efficiency

At least I'm consistent.  For the past five or so all grain batches I've been calculating my mash efficiency in the fifties.  My last two were the best at 59%.  I hear others obtaining. 80%.  So I'm I calculating or measuring wrong? Or is my technique wrong?
Example from yesterdays brew:
Mashed 11.5lb grain in 32 quart cooler/mash tun with 4  gallon of strike water at 164°F, resting at 153°F for 60 min, stirring every 15 minutes with only a drop of 4 degrees by the end of the mash.
First running collected approx 3 gallons with SG 1.071 and pH 5.0. Sparked with 4.5 gallons water at 168°F stirred and rested for fifteen minutes. Drained and collected 6.5 gallons of wort total with SG  1.040.
I believe the correct calculation is:
Total wort collected X OG / total grain bill.
In my case 59%.

Can someone help me with this...feel like I'm missing something.

Are you calculating or is BeerSmith? It's on the mash page. It gives the estimated mash efficiency and the measured based on measurements you took.

You don't give enough information for anyone to do any math. We would need the ppppg of the grain you used.
It's the ppppg of the grain vs what you actually got for ppppg of the wort. If you got 1.068 for 1 gallon of wort out of 2lbs of grain that had a ppppg of 1.034 that would be 100%.

The only thing that raises an eyebrow with me out of what you said is a pH of 5.0. 5.2 is actually the low end of the sweet spot for mashing.
If you are mashing below 5.2 (and you can't trust papers to be accurate enough for .2 so there's no big panic here) that could hurt your conversion as much as mashing above the sweet spot.

Thanks for the start.  Let me do some research and play with beersmith some more.  As for the pH...fist time I took the measurement to see if I need to make mash/water corrections.
Thanks.

Using my quick adjust tool, I entered the total points of 40, a ppg 38, efficiency of 60% on a 6.5g batch and get 11.4lbs of grain needed.  Therefore, it looks like you are getting around 60% efficiency.

Either your final volume is off or your sparge method is very inefficient.  What sort of manifold or screen do you have? how fast are you draining the cooler?

Stirring is unnecessary and increases the heat loss.

Ok..ppg,  I've seen it and read a out it, but haven't applied it yet.  I'm still learning and I got to study somethings some more.
My mash tun is an older cooler and my manifold is a SS heater hose with the rubber lining removed.  I drain the mash with the ball valve halfway to three quarters open. 

After furthdtfurther studing and reviewI I calculated my "Mash Extraction" to be 23 ppg.

From reading Palmer, this indicates poor mash conversion and some factors to look at include the grist, temp, time, and pH. Grist was done at HB shop, temp was 153°F and only dropped to 150°F in 60 min. Again, pH was between 5.0-5.2, usingtest strips.
Another question came up regarding my 1.25 quarts per pounds of strike water that beer smith calculated. I think im going to change my strike water to what Palmer recommends, 1.5 quarts per lb.

In regards to Mash Efficiency do I need the "max ppg" or "as-is ppg"?

GoodisBeer said:

After furthdtfurther studing and reviewI I calculated my "Mash Extraction" to be 23 ppg.

(6.5g × 40 pg ) ÷11.5lb =23ppg​

Click to expand...

PPG is simply the theoretical maximum extraction.  60% efficiency is 23 points of a potential 38 (depends on the grain of course).

GoodisBeer said:

From reading Palmer, this indicates poor mash conversion and some factors to look at include the grist, temp, time, and pH. Grist was done at HB shop, temp was 153°F and only dropped to 150°F in 60 min. Again, pH was between 5.0-5.2, usingtest strips.

Click to expand...

The crush from the HB shop could be too big.  If you can, run them through their mill twice.  The rest is fine.

GoodisBeer said:

Another question came up regarding my 1.25 quarts per pounds of strike water that beer smith calculated. I think im going to change my strike water to what Palmer recommends, 1.5 quarts per lb.

Click to expand...

This will not affect your efficiency much.  Check out Kai's the work  at
http://braukaiser.com/wiki/index.php?title=Braukaiser.com

GoodisBeer said:

In regards to Mash Efficiency do I need the "max ppg" or "as-is ppg"?

Click to expand...

I look at max but with a grain of salt.

I believe your efficiency is affected by your process and system.  The manifold or screen is not optimized for your sparge method.  In my system, I have a rectangular manifold much like Palmer has in hid book.  I started doing a fly sparge but found my efficiency was 60% after several batches.  I switch to a batch sparge process and increased to 75%-80%.  I am pretty consistent in this range now. 

My process is:
- preheat my igloo cooler
- Fill with strike water
- Add grains and stir away clumps
- wait an hour
- Vorlauf about 12 quarts, slowly at 12 min quart (You are doing this, right?)
- Drain wort. OPen valve 1/4 first, then move to half then wide open over 30 seconds
- Drain until completely empty
- Add batch water (usually 172F)
- Stir and Rest 10 - 15 minutes
- Repeat Vorlauf and other steps