All Grain problems, possible crush issues?

I am hoping to get help on my efficiency problems. This last batch I got about 40%, and missed my target by a good bit.

I am using a 10 gallon beverage cooler with a bazooka tube.

This last 5 gallon batch had 16lbs 6 oz of grain as follows:

11 lbs Pale Malt (2 Row) US
5 lbs Munich Malt
1 lbs Peat Smoked Malt
6.0 oz Black (Patent) Malt

I added 1.5 ratio to total 26 quarts, including dead space, at 165.5 and nailed my target temp of 156 for a full bodied beer. I held it there for an hour, and only lost 2 degrees.

Vorloft till clear and drained the wort. Then I batched sparged (stirred and recirculated) the rest of the water in 2 equal batches at 168 degrees to get my total of 6.5 gallons.

I think my pre-boil should have been 1.073, but was more like 1.04.

All I can think of is I am missing something completely or the way they are crushing the grains at the store is wrong.

Any help?

Not to state the obvious, but is your thermometer reading correctly (~212 degrees at boil), is your refractometer/hydrometer reading accurately (calibrate with appropriate temp distilled water), and was your sample the correct temperature for the instrument.

Yea, i checked all that. I had this issue two batches ago (50%), but the last one was near 75%. I thought I had all the kinks sorted out.

I'm using tap water, can water chemistry play that big a difference? I have no idea what my PH level is...

Was the pre-boil gravity reading after temperature correction? Where do you purchase your grains from and how do you store them?

I am using a refractometer, so getting the temp down wasn't an issue. I buy the grains milled from a local homebrew store and store them at room temp (78). from milled to brewday it was 2 days.

How do you add in your grain? Do you dump the grain in water or water onto the grain? If you dump the water onto the grain you can get some pretty nasty doughballs where not all the grain is getting mashed because it is all clumped together. Even if you are adding grain to water you can still get some clumps if you don't stir enough so; how well do you stir your mash? Doughballs can really drag down your efficiency. Just a thought.

It also never hurts to run the grain through a store mill twice. If it's online order sometimes you can write notes to them and request this.

I add the grain to the water then stir pretty good with a paddle. I think i might have to ask them to run it though twice. I saw a few grains that look like they hadn't been crushed at all.

What's your flow rate during sparging ...Are you going to fast, I am still trying to dial in my process also....I think I maybe rushing the sparge too. I thought I read somewhere you really want to take your time..

Could this be an issue ??...........Anyone

I'm batch sparging, so not too slow. I bet its taking me 20 min to do two batches.

Since you have a refractometer, measure the gravity of the first runnings. Then at least you will have an idea if something funny happened during conversion. Read this: http://braukaiser.com/wiki/index.php?title=Understanding_Efficiency#Measuring_conversion_efficiency

It seems with a 16+ pounds of grain, and only 6.5 gal preboil volume, mashing with 1.5 qt/lb would give you only a couple of gallons of sparge water. If you split that into two additions, it should be super thick... Can get the grain bed mixed with the sparge water well enough to effectively extract the remaining sugars? I understand that the two additions should increase efficiency, but I am just wondering if you aren't making your life too complicated.

Crush is the first thing to fix -- if the grain isn't crushed, you wont get good extraction. But testing the gravity of each runnings will help you troubleshoot, and you can always use a bit more sparge water and go to a 75 minute boil.

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Interesting read. I think I might investigate the PH on the side, but focus on the crush.

I also think that next time I batch sparge, I'll combine into one batch or decrease the initial ratio.