[matt.ballard.587]

Today i ran a batch of scottish ale using the countertop partial mash technique from byo.  I only got 46 percent efficiency from the grains. 
I used  1.75 lbs of 2 row base malt, .6 lbs of crystal 40, .3 lbs of honey malt, .15 lbs of crystal 120, .11 lbs pale chocolate. 
I placed the grains into the grain bag and mashed in at 169 to get a temperature of 158. Using 1.375 quarts/ pound of grain.   Turns out that when i put my thermometer into the mash it only showed 154.   It sat there for 30 min.  About 15 min in i checked the temp and it was only 146, so i added 1 cup of boiling water to get it back into the 150's. 
I sparged with the same amount of water at 175. Letting it sit 5 min before i drained the cooler the second time. 
Doing the math i only pulled 48 points out of a max of 105.  Can anyone see what i did wrong to only get ths 46% efficiency

[Stevie]

Double crush you grain or buy your own mill. The mill at my LHBS is wildly inconsistent so I got a mill.

[HoosierBrew]

+1 to double crush or buy a mill.  Also, are your volumes accurate ? You only have to be a small amount over or under your target batch volume to throw gravity readings off by several points. And poor pH control will interfere with the process, too.

[dmtaylor]

Double crush you grain or buy your own mill. The mill at my LHBS is wildly inconsistent so I got a mill.

This.

AND... you need to nail your volumes.  If you get an extra couple of quarts volume at the end of all this, it will hose up your calculations big time.

[matt.ballard.587]

I originally thought i had pulled out 78 points. But i was off on my boil volume.  I had thought i was boiling 2 gallons.  I found out when i was done with the boil i only had 1.5 gallons of wort.  And i had a lot of suspended solids in the original gravity i had taken when i started the boil

[matt.ballard.587]

And i was measuring the water out as i went

[morticaixavier]

that grain bill maxes out at just under 105 points. in a 1.5 gallon batch that's a maximum of 70 points. if you got ~70% efficiency you would get 49 points so you got about 65% efficiency.

[Stevie]

Suspended solids shouldn't matter much if at all.

[erockrph]

A) Use a very fine-mesh bag
B) Squeeze the hell out of your bag

Especially at such a small volume, I'd expect a big efficiency boost doing this.

[matt.ballard.587]

I expected something around 73 points out of it.

And only got  48. 

[aokeovn]

There is always the error here.  housse galaxy alpha etui samsung galaxy alpha

[morticaixavier]

I expected something around 73 points out of it.

And only got  48.

how many gallons are we talking?

grain is effectively 36 ppg you've got 2.91 lbs of grain there. that's 2.91 * 36 = 104.76 total points. that's 100% efficiency in 1 gallon of wort. It's also more or less impossible on the home scale. you said you got 1.5 gallons. was that at the end of the boil or the begining?

1.5 gallons at 1.048 is 72 points. 72/104.76 = 68.72%

[matt.ballard.587]

That was at the end of the 60 min boil

[matt.ballard.587]

And my og was 1.032

[morticaixavier]

okay.

So in that case first thing to look at is your crush, as others have mentioned. next is mash thickness. aim for more like 2 qt/lb. the thinner mash will help your efficiency some but mostly it will help you to make sure everything is well stirred up.

then you get into mash chemistry. keep it simple and start with RO water. download the bru'n water spreadsheet and read the water knowledge page.

it's also important to determine what your conversion efficiency is in order to know if you didn't convert the sugars or didn't extract them from the mash. if the conversion is there then it's an extraction issue and you can just sparge more.