Efficiency Questions/Problems

[Tumpster]

So, I have a Coleman 70-quart Xtreme Cooler converted for batch sparging and brewed up a Smoked Breakfast Stout today. Preboil gravity came in at 1.030 and gravity after boiling came in at 1.050. I was targeting for about 1.075, the recipe is as follows

10.5lbs 2Row
4lbs Dark Munich
.5lb Kiln Coffee Malt
1LB Flaked Oats
.5lb Caramel 80L
1lb Black Malt
.25lb Cherrywood Smoked Malt

My process is as follows: Boil up mash water to about 166-168, use this water to heat mash tun, dough in at about 163-164 usually results in about temps of 154-155, pending style I let it cool to 152-153 and mash for 60 minutes. When it comes time to sparge I boil up the amount of water needed to 170 and slowly add it to the grain bed as the run off is occurring to my kettle. I use this link for my water to grain conversions and how much water I need: Mash and Sparge Water Calculator ::: Brew365 - Homebrewing Recipes and Articles This beer I boiled for 90 minutes.

Where could I be having this crappy of effiecency and what could I be doing wrong? I've had batches hit right at or near there SG I was targeting in the past but more often then not I've missed it, but not by this much. I'm open to suggestions or ideas. My apologies for the long winded post.

 

[ETCS]

slowly add it to the grain bed as the run off is occurring to my kettle.

If you batch sparge, you should completely drain your Mash Tun...Add sparge water...stir....wait for the grain bed to settle...recirculate the mash (again) until it runs clear (not full of little bits of grain)...and drain it again to the boil kettle. Depending on the volume in the brew kettle, you might need to do this twice. Hope this helps...Cheers.